Bug#54916 GROUP_CONCAT + IFNULL truncates output

Problem: a few functions did not calculate their max_length correctly.
This is an after-fix for WL#2649 Number-to-string conversions".

Fix: changing the buggy functions to calculate max_length
using fix_char_length() introduced in WL#2649,
instead of setting max_length directly

  mysql-test/include/ctype_numconv.inc
     Adding new tests

  mysql-test/r/ctype_binary.result
     Adding new tests

  mysql-test/r/ctype_cp1251.result
     Adding new tests

  mysql-test/r/ctype_latin1.result
     Adding new tests

  mysql-test/r/ctype_ucs.result
     Adding new tests

  mysql-test/r/ctype_utf8.result
     Adding new tests

  mysql-test/t/ctype_utf8.test
    Including ctype_numconv

  sql/item.h
    - Introducing new method fix_char_length_ulonglong(),
    for the cases when length is potentially greater
    than UINT_MAX32. This method removes a few
    instances of duplicate code, e.g. in item_strfunc.cc.
    - Setting collation in Item_copy properly. This change
    fixes wrong metadata on client side in some cases, when
    "binary" instead of the real character set was reported.

  sql/item_cmpfunc.cc
    - Using fix_char_length() and max_char_length() methods,
    instead of direct access to max_length, to calculate
    item length properly.
    - Moving count_only_length() in COALESCE after
    agg_arg_charsets_for_string_result(). The old
    order was incorrect and led to wrong length
    calucation in case of multi-byte character sets.
    
  sql/item_func.cc
    Fixing that count_only_length() didn't work
    properly for multi-byte character sets.
    Using fix_char_length() and max_char_length()
    instead of direct access to max_length.

  sql/item_strfunc.cc
    - Using fix_char_length(), fix_char_length_ulonglong(),
    max_char_length() instead of direct access to max_length.
    - Removing wierd condition: "if (collation.collation->mbmaxlen > 0)",
    which is never FALSE.

mysql-test/include/ctype_numconv.inc

@@ -1625,6 +1625,108 @@ SET @x=aswkt(point(1,2));
 SELECT charset(@x), collation(@x);
 
 
+--echo #
+--echo # Bug#54916 GROUP_CONCAT + IFNULL truncates output
+--echo #
+SELECT @@collation_connection;
+# ENGINE=MYISAM is very important to make sure "SYSTEM" join type
+# is in use, which will create instances of Item_copy.
+CREATE TABLE t1 (a MEDIUMINT NULL) ENGINE=MYISAM;
+INSERT INTO t1 VALUES (1234567);
+SELECT GROUP_CONCAT(IFNULL(a,'')) FROM t1;
+SELECT GROUP_CONCAT(IF(a,a,'')) FROM t1;
+if (`SELECT @@character_set_connection != 'ucs2'`)
+{
+  # Temporarily disable for ucs2
+  # For details, see Bug#55744 GROUP_CONCAT + CASE + ucs return garbage
+  SELECT GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END) FROM t1;
+}
+--enable_metadata
+SELECT COALESCE(a,'') FROM t1 GROUP BY 1;
+--disable_metadata
+--echo # All columns must be VARCHAR(9) with the same length:
+--disable_warnings
+CREATE TABLE t2 AS
+SELECT
+  CONCAT(a),
+  IFNULL(a,''),
+  IF(a,a,''),
+  CASE WHEN a THEN a ELSE '' END,
+  COALESCE(a,'')
+FROM t1;
+--enable_warnings
+# The above query is expected to send a warning
+# in case of ucs2 character set, until Bug#55744 is fixed.
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT CONCAT_WS(1,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT INSERT(1133,3,0,22) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT LCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT UCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT REPEAT(1,2) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT LEFT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT RIGHT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT LTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT RTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT ELT(1,111,222,333) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT REPLACE(111,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT SUBSTRING_INDEX(111,111,1) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT MAKE_SET(111,222,3) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT SOUNDEX(1) FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+CREATE TABLE t2 AS SELECT EXPORT_SET(1,'Y','N','',8);
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+
+DROP TABLE t1;
+
+--echo #
+--echo # End of Bug#54916
+--echo #
+
+
 --echo #
 --echo # Bug#52159 returning time type from function and empty left join causes debug assertion
 --echo #

mysql-test/r/case.result

@@ -160,6 +160,8 @@ t1	CREATE TABLE `t1` (
   `COALESCE('a' COLLATE latin1_bin,'b')` varchar(1) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT ''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 DROP TABLE t1;
+CREATE TABLE t1 SELECT IFNULL('a' COLLATE latin1_swedish_ci, 'b' COLLATE latin1_bin);
+ERROR HY000: Illegal mix of collations (latin1_swedish_ci,EXPLICIT) and (latin1_bin,EXPLICIT) for operation 'ifnull'
 SELECT 'case+union+test'
 UNION 
 SELECT CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END;

mysql-test/r/ctype_binary.result

@@ -2598,6 +2598,156 @@ SELECT charset(@x), collation(@x);
 charset(@x)	collation(@x)
 binary	binary
 #
+# Bug#54916 GROUP_CONCAT + IFNULL truncates output
+#
+SELECT @@collation_connection;
+@@collation_connection
+binary
+CREATE TABLE t1 (a MEDIUMINT NULL) ENGINE=MYISAM;
+INSERT INTO t1 VALUES (1234567);
+SELECT GROUP_CONCAT(IFNULL(a,'')) FROM t1;
+GROUP_CONCAT(IFNULL(a,''))
+1234567
+SELECT GROUP_CONCAT(IF(a,a,'')) FROM t1;
+GROUP_CONCAT(IF(a,a,''))
+1234567
+SELECT GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END) FROM t1;
+GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END)
+1234567
+SELECT COALESCE(a,'') FROM t1 GROUP BY 1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					COALESCE(a,'')	253	9	7	Y	128	31	63
+COALESCE(a,'')
+1234567
+# All columns must be VARCHAR(9) with the same length:
+CREATE TABLE t2 AS
+SELECT
+CONCAT(a),
+IFNULL(a,''),
+IF(a,a,''),
+CASE WHEN a THEN a ELSE '' END,
+COALESCE(a,'')
+FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT(a)` varbinary(9) DEFAULT NULL,
+  `IFNULL(a,'')` varbinary(9) NOT NULL DEFAULT '',
+  `IF(a,a,'')` varbinary(9) DEFAULT NULL,
+  `CASE WHEN a THEN a ELSE '' END` varbinary(9) DEFAULT NULL,
+  `COALESCE(a,'')` varbinary(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT CONCAT_WS(1,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT_WS(1,2,3)` varbinary(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT INSERT(1133,3,0,22) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `INSERT(1133,3,0,22)` varbinary(6) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LCASE(a)` varbinary(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT UCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `UCASE(a)` varbinary(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPEAT(1,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPEAT(1,2)` varbinary(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LEFT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LEFT(123,2)` varbinary(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RIGHT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RIGHT(123,2)` varbinary(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LTRIM(123)` varbinary(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RTRIM(123)` varbinary(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT ELT(1,111,222,333) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `ELT(1,111,222,333)` varbinary(3) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPLACE(111,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPLACE(111,2,3)` varbinary(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SUBSTRING_INDEX(111,111,1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SUBSTRING_INDEX(111,111,1)` varbinary(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT MAKE_SET(111,222,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `MAKE_SET(111,222,3)` varbinary(5) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SOUNDEX(1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SOUNDEX(1)` varbinary(4) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT EXPORT_SET(1,'Y','N','',8);
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `EXPORT_SET(1,'Y','N','',8)` varbinary(64) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP TABLE t1;
+#
+# End of Bug#54916
+#
+#
 # Bug#52159 returning time type from function and empty left join causes debug assertion
 #
 CREATE FUNCTION f1() RETURNS TIME RETURN 1;

mysql-test/r/ctype_cp1251.result

@@ -2680,6 +2680,156 @@ SELECT charset(@x), collation(@x);
 charset(@x)	collation(@x)
 cp1251	cp1251_general_ci
 #
+# Bug#54916 GROUP_CONCAT + IFNULL truncates output
+#
+SELECT @@collation_connection;
+@@collation_connection
+cp1251_general_ci
+CREATE TABLE t1 (a MEDIUMINT NULL) ENGINE=MYISAM;
+INSERT INTO t1 VALUES (1234567);
+SELECT GROUP_CONCAT(IFNULL(a,'')) FROM t1;
+GROUP_CONCAT(IFNULL(a,''))
+1234567
+SELECT GROUP_CONCAT(IF(a,a,'')) FROM t1;
+GROUP_CONCAT(IF(a,a,''))
+1234567
+SELECT GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END) FROM t1;
+GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END)
+1234567
+SELECT COALESCE(a,'') FROM t1 GROUP BY 1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					COALESCE(a,'')	253	9	7	Y	0	31	51
+COALESCE(a,'')
+1234567
+# All columns must be VARCHAR(9) with the same length:
+CREATE TABLE t2 AS
+SELECT
+CONCAT(a),
+IFNULL(a,''),
+IF(a,a,''),
+CASE WHEN a THEN a ELSE '' END,
+COALESCE(a,'')
+FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT(a)` varchar(9) CHARACTER SET cp1251 DEFAULT NULL,
+  `IFNULL(a,'')` varchar(9) CHARACTER SET cp1251 NOT NULL DEFAULT '',
+  `IF(a,a,'')` varchar(9) CHARACTER SET cp1251 DEFAULT NULL,
+  `CASE WHEN a THEN a ELSE '' END` varchar(9) CHARACTER SET cp1251 DEFAULT NULL,
+  `COALESCE(a,'')` varchar(9) CHARACTER SET cp1251 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT CONCAT_WS(1,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT_WS(1,2,3)` varchar(3) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT INSERT(1133,3,0,22) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `INSERT(1133,3,0,22)` varchar(6) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LCASE(a)` varchar(9) CHARACTER SET cp1251 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT UCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `UCASE(a)` varchar(9) CHARACTER SET cp1251 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPEAT(1,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPEAT(1,2)` varchar(2) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LEFT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LEFT(123,2)` varchar(2) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RIGHT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RIGHT(123,2)` varchar(2) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LTRIM(123)` varchar(3) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RTRIM(123)` varchar(3) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT ELT(1,111,222,333) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `ELT(1,111,222,333)` varchar(3) CHARACTER SET cp1251 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPLACE(111,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPLACE(111,2,3)` varchar(3) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SUBSTRING_INDEX(111,111,1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SUBSTRING_INDEX(111,111,1)` varchar(3) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT MAKE_SET(111,222,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `MAKE_SET(111,222,3)` varchar(5) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SOUNDEX(1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SOUNDEX(1)` varchar(4) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT EXPORT_SET(1,'Y','N','',8);
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `EXPORT_SET(1,'Y','N','',8)` varchar(64) CHARACTER SET cp1251 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP TABLE t1;
+#
+# End of Bug#54916
+#
+#
 # Bug#52159 returning time type from function and empty left join causes debug assertion
 #
 CREATE FUNCTION f1() RETURNS TIME RETURN 1;

mysql-test/r/ctype_latin1.result

@@ -3008,6 +3008,156 @@ SELECT charset(@x), collation(@x);
 charset(@x)	collation(@x)
 latin1	latin1_swedish_ci
 #
+# Bug#54916 GROUP_CONCAT + IFNULL truncates output
+#
+SELECT @@collation_connection;
+@@collation_connection
+latin1_swedish_ci
+CREATE TABLE t1 (a MEDIUMINT NULL) ENGINE=MYISAM;
+INSERT INTO t1 VALUES (1234567);
+SELECT GROUP_CONCAT(IFNULL(a,'')) FROM t1;
+GROUP_CONCAT(IFNULL(a,''))
+1234567
+SELECT GROUP_CONCAT(IF(a,a,'')) FROM t1;
+GROUP_CONCAT(IF(a,a,''))
+1234567
+SELECT GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END) FROM t1;
+GROUP_CONCAT(CASE WHEN a THEN a ELSE '' END)
+1234567
+SELECT COALESCE(a,'') FROM t1 GROUP BY 1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					COALESCE(a,'')	253	9	7	Y	0	31	8
+COALESCE(a,'')
+1234567
+# All columns must be VARCHAR(9) with the same length:
+CREATE TABLE t2 AS
+SELECT
+CONCAT(a),
+IFNULL(a,''),
+IF(a,a,''),
+CASE WHEN a THEN a ELSE '' END,
+COALESCE(a,'')
+FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT(a)` varchar(9) DEFAULT NULL,
+  `IFNULL(a,'')` varchar(9) NOT NULL DEFAULT '',
+  `IF(a,a,'')` varchar(9) DEFAULT NULL,
+  `CASE WHEN a THEN a ELSE '' END` varchar(9) DEFAULT NULL,
+  `COALESCE(a,'')` varchar(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT CONCAT_WS(1,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT_WS(1,2,3)` varchar(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT INSERT(1133,3,0,22) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `INSERT(1133,3,0,22)` varchar(6) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LCASE(a)` varchar(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT UCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `UCASE(a)` varchar(9) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPEAT(1,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPEAT(1,2)` varchar(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LEFT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LEFT(123,2)` varchar(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RIGHT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RIGHT(123,2)` varchar(2) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LTRIM(123)` varchar(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RTRIM(123)` varchar(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT ELT(1,111,222,333) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `ELT(1,111,222,333)` varchar(3) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPLACE(111,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPLACE(111,2,3)` varchar(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SUBSTRING_INDEX(111,111,1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SUBSTRING_INDEX(111,111,1)` varchar(3) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT MAKE_SET(111,222,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `MAKE_SET(111,222,3)` varchar(5) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SOUNDEX(1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SOUNDEX(1)` varchar(4) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT EXPORT_SET(1,'Y','N','',8);
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `EXPORT_SET(1,'Y','N','',8)` varchar(64) NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP TABLE t1;
+#
+# End of Bug#54916
+#
+#
 # Bug#52159 returning time type from function and empty left join causes debug assertion
 #
 CREATE FUNCTION f1() RETURNS TIME RETURN 1;

mysql-test/r/ctype_ucs.result

@@ -3840,6 +3840,153 @@ SELECT charset(@x), collation(@x);
 charset(@x)	collation(@x)
 ucs2	ucs2_general_ci
 #
+# Bug#54916 GROUP_CONCAT + IFNULL truncates output
+#
+SELECT @@collation_connection;
+@@collation_connection
+ucs2_general_ci
+CREATE TABLE t1 (a MEDIUMINT NULL) ENGINE=MYISAM;
+INSERT INTO t1 VALUES (1234567);
+SELECT GROUP_CONCAT(IFNULL(a,'')) FROM t1;
+GROUP_CONCAT(IFNULL(a,''))
+1234567
+SELECT GROUP_CONCAT(IF(a,a,'')) FROM t1;
+GROUP_CONCAT(IF(a,a,''))
+1234567
+SELECT COALESCE(a,'') FROM t1 GROUP BY 1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					COALESCE(a,'')	253	9	7	Y	0	31	8
+COALESCE(a,'')
+1234567
+# All columns must be VARCHAR(9) with the same length:
+CREATE TABLE t2 AS
+SELECT
+CONCAT(a),
+IFNULL(a,''),
+IF(a,a,''),
+CASE WHEN a THEN a ELSE '' END,
+COALESCE(a,'')
+FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT(a)` varchar(9) CHARACTER SET ucs2 DEFAULT NULL,
+  `IFNULL(a,'')` varchar(9) CHARACTER SET ucs2 NOT NULL DEFAULT '',
+  `IF(a,a,'')` varchar(9) CHARACTER SET ucs2 DEFAULT NULL,
+  `CASE WHEN a THEN a ELSE '' END` varchar(9) CHARACTER SET ucs2 DEFAULT NULL,
+  `COALESCE(a,'')` varchar(9) CHARACTER SET ucs2 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT CONCAT_WS(1,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `CONCAT_WS(1,2,3)` varchar(3) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT INSERT(1133,3,0,22) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `INSERT(1133,3,0,22)` varchar(6) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LCASE(a)` varchar(9) CHARACTER SET ucs2 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT UCASE(a) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `UCASE(a)` varchar(9) CHARACTER SET ucs2 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPEAT(1,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPEAT(1,2)` varchar(2) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LEFT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LEFT(123,2)` varchar(2) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RIGHT(123,2) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RIGHT(123,2)` varchar(2) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT LTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `LTRIM(123)` varchar(3) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT RTRIM(123) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `RTRIM(123)` varchar(3) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT ELT(1,111,222,333) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `ELT(1,111,222,333)` varchar(3) CHARACTER SET ucs2 DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT REPLACE(111,2,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `REPLACE(111,2,3)` varchar(3) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SUBSTRING_INDEX(111,111,1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SUBSTRING_INDEX(111,111,1)` varchar(3) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT MAKE_SET(111,222,3) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `MAKE_SET(111,222,3)` varchar(5) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT SOUNDEX(1) FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `SOUNDEX(1)` varchar(4) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+CREATE TABLE t2 AS SELECT EXPORT_SET(1,'Y','N','',8);
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `EXPORT_SET(1,'Y','N','',8)` varchar(64) CHARACTER SET ucs2 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP TABLE t1;
+#
+# End of Bug#54916
+#
+#
 # Bug#52159 returning time type from function and empty left join causes debug assertion
 #
 CREATE FUNCTION f1() RETURNS TIME RETURN 1;

mysql-test/t/case.test

@@ -111,6 +111,9 @@ explain extended SELECT
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
+--error 1267
+CREATE TABLE t1 SELECT IFNULL('a' COLLATE latin1_swedish_ci, 'b' COLLATE latin1_bin);
+
 # Test for BUG#10151
 SELECT 'case+union+test'
 UNION 

mysql-test/t/ctype_utf8.test

@@ -1505,6 +1505,11 @@ CREATE TABLE t2 AS SELECT CONCAT(s1) FROM t1;
 SHOW CREATE TABLE t2;
 DROP TABLE t1, t2;
 
+
+SET NAMES utf8;
+--source include/ctype_numconv.inc
+
+
 --echo #
 --echo # End of 5.5 tests
 --echo #

sql/item.h

@@ -547,7 +547,7 @@ public:
      @see Query_arena::free_list
    */
   Item *next;
-  uint32 max_length;
+  uint32 max_length;                    /* Maximum length, in bytes */
   uint name_length;                     /* Length of name */
   int8 marker;
   uint8 decimals;
@@ -1221,6 +1221,18 @@ public:
     max_length= char_to_byte_length_safe(max_char_length_arg,
                                          collation.collation->mbmaxlen);
   }
+  void fix_char_length_ulonglong(ulonglong max_char_length_arg)
+  {
+    ulonglong max_result_length= max_char_length_arg *
+                                 collation.collation->mbmaxlen;
+    if (max_result_length >= MAX_BLOB_WIDTH)
+    {
+      max_length= MAX_BLOB_WIDTH;
+      maybe_null= 1;
+    }
+    else
+      max_length= max_result_length;
+  }
   void fix_length_and_charset_datetime(uint32 max_char_length_arg)
   {
     collation.set(&my_charset_numeric, DERIVATION_NUMERIC, MY_REPERTOIRE_ASCII);
@@ -2825,6 +2837,7 @@ protected:
     cached_result_type= item->result_type();
     unsigned_flag= item->unsigned_flag;
     fixed= item->fixed;
+    collation.set(item->collation);
   }
 
 public:

sql/item_cmpfunc.cc

@@ -2374,6 +2374,7 @@ void Item_func_between::print(String *str, enum_query_type query_type)
 void
 Item_func_ifnull::fix_length_and_dec()
 {
+  uint32 char_length;
   agg_result_type(&hybrid_type, args, 2);
   maybe_null=args[1]->maybe_null;
   decimals= max(args[0]->decimals, args[1]->decimals);
@@ -2381,20 +2382,21 @@ Item_func_ifnull::fix_length_and_dec()
 
   if (hybrid_type == DECIMAL_RESULT || hybrid_type == INT_RESULT) 
   {
-    int len0= args[0]->max_length - args[0]->decimals
+    int len0= args[0]->max_char_length() - args[0]->decimals
       - (args[0]->unsigned_flag ? 0 : 1);
 
-    int len1= args[1]->max_length - args[1]->decimals
+    int len1= args[1]->max_char_length() - args[1]->decimals
       - (args[1]->unsigned_flag ? 0 : 1);
 
-    max_length= max(len0, len1) + decimals + (unsigned_flag ? 0 : 1);
+    char_length= max(len0, len1) + decimals + (unsigned_flag ? 0 : 1);
   }
   else
-    max_length= max(args[0]->max_length, args[1]->max_length);
+    char_length= max(args[0]->max_char_length(), args[1]->max_char_length());
 
   switch (hybrid_type) {
   case STRING_RESULT:
-    agg_arg_charsets_for_comparison(collation, args, arg_count);
+    if (agg_arg_charsets_for_comparison(collation, args, arg_count))
+      return;
     break;
   case DECIMAL_RESULT:
   case REAL_RESULT:
@@ -2406,6 +2408,7 @@ Item_func_ifnull::fix_length_and_dec()
   default:
     DBUG_ASSERT(0);
   }
+  fix_char_length(char_length);
   cached_field_type= agg_field_type(args, 2);
 }
 
@@ -2579,6 +2582,7 @@ Item_func_if::fix_length_and_dec()
     cached_field_type= agg_field_type(args + 1, 2);
   }
 
+  uint32 char_length;
   if ((cached_result_type == DECIMAL_RESULT )
       || (cached_result_type == INT_RESULT))
   {
@@ -2588,10 +2592,11 @@ Item_func_if::fix_length_and_dec()
     int len2= args[2]->max_length - args[2]->decimals
       - (args[2]->unsigned_flag ? 0 : 1);
 
-    max_length=max(len1, len2) + decimals + (unsigned_flag ? 0 : 1);
+    char_length= max(len1, len2) + decimals + (unsigned_flag ? 0 : 1);
   }
   else
-    max_length= max(args[1]->max_length, args[2]->max_length);
+    char_length= max(args[1]->max_char_length(), args[2]->max_char_length());
+  fix_char_length(char_length);
 }
 
 
@@ -2901,7 +2906,7 @@ bool Item_func_case::fix_fields(THD *thd, Item **ref)
 
 void Item_func_case::agg_str_lengths(Item* arg)
 {
-  set_if_bigger(max_length, arg->max_length);
+  fix_char_length(max(max_char_length(), arg->max_char_length()));
   set_if_bigger(decimals, arg->decimals);
   unsigned_flag= unsigned_flag && arg->unsigned_flag;
 }
@@ -3129,9 +3134,10 @@ void Item_func_coalesce::fix_length_and_dec()
   agg_result_type(&hybrid_type, args, arg_count);
   switch (hybrid_type) {
   case STRING_RESULT:
-    count_only_length();
     decimals= NOT_FIXED_DEC;
-    agg_arg_charsets_for_string_result(collation, args, arg_count);
+    if (agg_arg_charsets_for_string_result(collation, args, arg_count))
+      return;
+    count_only_length();
     break;
   case DECIMAL_RESULT:
     count_decimal_length();

sql/item_func.cc

@@ -564,8 +564,9 @@ void Item_func::count_decimal_length()
     set_if_smaller(unsigned_flag, args[i]->unsigned_flag);
   }
   int precision= min(max_int_part + decimals, DECIMAL_MAX_PRECISION);
-  max_length= my_decimal_precision_to_length_no_truncation(precision, decimals,
+  fix_char_length(my_decimal_precision_to_length_no_truncation(precision,
-                                                           unsigned_flag);
+                                                               decimals,
+                                                               unsigned_flag));
 }
 
 
@@ -575,13 +576,14 @@ void Item_func::count_decimal_length()
 
 void Item_func::count_only_length()
 {
-  max_length= 0;
+  uint32 char_length= 0;
   unsigned_flag= 0;
   for (uint i=0 ; i < arg_count ; i++)
   {
-    set_if_bigger(max_length, args[i]->max_length);
+    set_if_bigger(char_length, args[i]->max_char_length());
     set_if_bigger(unsigned_flag, args[i]->unsigned_flag);
   }
+  fix_char_length(char_length);
 }
 
 

sql/item_strfunc.cc

@@ -605,27 +605,15 @@ null:
 
 void Item_func_concat::fix_length_and_dec()
 {
-  ulonglong max_result_length= 0;
+  ulonglong char_length= 0;
 
   if (agg_arg_charsets_for_string_result(collation, args, arg_count))
     return;
 
   for (uint i=0 ; i < arg_count ; i++)
-  {
+    char_length+= args[i]->max_char_length();
-    if (args[i]->collation.collation->mbmaxlen != collation.collation->mbmaxlen)
-      max_result_length+= (args[i]->max_length /
-                           args[i]->collation.collation->mbmaxlen) *
-                           collation.collation->mbmaxlen;
-    else
-      max_result_length+= args[i]->max_length;
-  }
 
-  if (max_result_length >= MAX_BLOB_WIDTH)
+  fix_char_length_ulonglong(char_length);
-  {
-    max_result_length= MAX_BLOB_WIDTH;
-    maybe_null= 1;
-  }
-  max_length= (ulong) max_result_length;
 }
 
 /**
@@ -962,7 +950,7 @@ null:
 
 void Item_func_concat_ws::fix_length_and_dec()
 {
-  ulonglong max_result_length;
+  ulonglong char_length;
 
   if (agg_arg_charsets_for_string_result(collation, args, arg_count))
     return;
@@ -972,16 +960,11 @@ void Item_func_concat_ws::fix_length_and_dec()
      it is done on parser level in sql_yacc.yy
      so, (arg_count - 2) is safe here.
   */
-  max_result_length= (ulonglong) args[0]->max_length * (arg_count - 2);
+  char_length= (ulonglong) args[0]->max_char_length() * (arg_count - 2);
   for (uint i=1 ; i < arg_count ; i++)
-    max_result_length+=args[i]->max_length;
+    char_length+= args[i]->max_char_length();
 
-  if (max_result_length >= MAX_BLOB_WIDTH)
+  fix_char_length_ulonglong(char_length);
-  {
-    max_result_length= MAX_BLOB_WIDTH;
-    maybe_null= 1;
-  }
-  max_length= (ulong) max_result_length;
 }
 
 
@@ -1036,6 +1019,7 @@ String *Item_func_reverse::val_str(String *str)
 void Item_func_reverse::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   fix_char_length(args[0]->max_char_length());
 }
 
@@ -1165,22 +1149,17 @@ null:
 
 void Item_func_replace::fix_length_and_dec()
 {
-  ulonglong max_result_length= args[0]->max_length;
+  ulonglong char_length= (ulonglong) args[0]->max_char_length();
-  int diff=(int) (args[2]->max_length - args[1]->max_length);
+  int diff=(int) (args[2]->max_char_length() - args[1]->max_char_length());
-  if (diff > 0 && args[1]->max_length)
+  if (diff > 0 && args[1]->max_char_length())
   {						// Calculate of maxreplaces
-    ulonglong max_substrs= max_result_length/args[1]->max_length;
+    ulonglong max_substrs= char_length / args[1]->max_char_length();
-    max_result_length+= max_substrs * (uint) diff;
+    char_length+= max_substrs * (uint) diff;
   }
-  if (max_result_length >= MAX_BLOB_WIDTH)
+
-  {
-    max_result_length= MAX_BLOB_WIDTH;
-    maybe_null= 1;
-  }
-  max_length= (ulong) max_result_length;
-  
   if (agg_arg_charsets_for_comparison(collation, args, 3))
     return;
+  fix_char_length_ulonglong(char_length);
 }
 
 
@@ -1235,19 +1214,14 @@ null:
 
 void Item_func_insert::fix_length_and_dec()
 {
-  ulonglong max_result_length;
+  ulonglong char_length;
 
   // Handle character set for args[0] and args[3].
   if (agg_arg_charsets_for_string_result(collation, args, 2, 3))
     return;
-  max_result_length= ((ulonglong) args[0]->max_length+
+  char_length= ((ulonglong) args[0]->max_char_length() +
-                      (ulonglong) args[3]->max_length);
+                (ulonglong) args[3]->max_char_length());
-  if (max_result_length >= MAX_BLOB_WIDTH)
+  fix_char_length_ulonglong(char_length);
-  {
-    max_result_length= MAX_BLOB_WIDTH;
-    maybe_null= 1;
-  }
-  max_length= (ulong) max_result_length;
 }
 
 
@@ -1287,17 +1261,19 @@ String *Item_str_conv::val_str(String *str)
 void Item_func_lcase::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   multiply= collation.collation->casedn_multiply;
   converter= collation.collation->cset->casedn;
-  max_length= args[0]->max_length * multiply;
+  fix_char_length_ulonglong((ulonglong) args[0]->max_char_length() * multiply);
 }
 
 void Item_func_ucase::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   multiply= collation.collation->caseup_multiply;
   converter= collation.collation->cset->caseup;
-  max_length= args[0]->max_length * multiply;
+  fix_char_length_ulonglong((ulonglong) args[0]->max_char_length() * multiply);
 }
 
 
@@ -1328,21 +1304,23 @@ String *Item_func_left::val_str(String *str)
 
 void Item_str_func::left_right_max_length()
 {
-  max_length=args[0]->max_length;
+  uint32 char_length= args[0]->max_char_length();
   if (args[1]->const_item())
   {
-    int length=(int) args[1]->val_int()*collation.collation->mbmaxlen;
+    int length= (int) args[1]->val_int();
     if (length <= 0)
-      max_length=0;
+      char_length=0;
     else
-      set_if_smaller(max_length,(uint) length);
+      set_if_smaller(char_length, (uint) length);
   }
+  fix_char_length(char_length);
 }
 
 
 void Item_func_left::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   left_right_max_length();
 }
 
@@ -1376,6 +1354,7 @@ String *Item_func_right::val_str(String *str)
 void Item_func_right::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   left_right_max_length();
 }
 
@@ -1432,6 +1411,7 @@ void Item_func_substr::fix_length_and_dec()
   max_length=args[0]->max_length;
 
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   if (args[1]->const_item())
   {
     int32 start= (int32) args[1]->val_int();
@@ -1454,10 +1434,9 @@ void Item_func_substr::fix_length_and_dec()
 
 void Item_func_substr_index::fix_length_and_dec()
 { 
-  max_length= args[0]->max_length;
-
   if (agg_arg_charsets_for_comparison(collation, args, 2))
     return;
+  fix_char_length(args[0]->max_char_length());
 }
 
 
@@ -1783,10 +1762,10 @@ String *Item_func_trim::val_str(String *str)
 
 void Item_func_trim::fix_length_and_dec()
 {
-  max_length= args[0]->max_length;
   if (arg_count == 1)
   {
     agg_arg_charsets_for_string_result(collation, args, 1);
+    DBUG_ASSERT(collation.collation != NULL);
     remove.set_charset(collation.collation);
     remove.set_ascii(" ",1);
   }
@@ -1797,6 +1776,7 @@ void Item_func_trim::fix_length_and_dec()
     if (agg_arg_charsets_for_comparison(collation, &args[1], 2, -1))
       return;
   }
+  fix_char_length(args[0]->max_char_length());
 }
 
 void Item_func_trim::print(String *str, enum_query_type query_type)
@@ -2072,9 +2052,11 @@ bool Item_func_current_user::fix_fields(THD *thd, Item **ref)
 
 void Item_func_soundex::fix_length_and_dec()
 {
+  uint32 char_length= args[0]->max_char_length();
   agg_arg_charsets_for_string_result(collation, args, 1);
-  max_length=args[0]->max_length;
+  DBUG_ASSERT(collation.collation != NULL);
-  set_if_bigger(max_length, 4 * collation.collation->mbminlen);
+  set_if_bigger(char_length, 4);
+  fix_char_length(char_length);
   tmp_value.set_charset(collation.collation);
 }
 
@@ -2251,11 +2233,10 @@ MY_LOCALE *Item_func_format::get_locale(Item *item)
 
 void Item_func_format::fix_length_and_dec()
 {
-  uint char_length= args[0]->max_length/args[0]->collation.collation->mbmaxlen;
+  uint32 char_length= args[0]->max_char_length();
-  uint max_sep_count= char_length/3 + (decimals ? 1 : 0) + /*sign*/1;
+  uint32 max_sep_count= (char_length / 3) + (decimals ? 1 : 0) + /*sign*/1;
   collation.set(default_charset());
-  max_length= (char_length + max_sep_count + decimals) *
+  fix_char_length(char_length + max_sep_count + decimals);
-    collation.collation->mbmaxlen;
   if (arg_count == 3)
     locale= args[2]->basic_const_item() ? get_locale(args[2]) : NULL;
   else
@@ -2375,7 +2356,7 @@ void Item_func_format::print(String *str, enum_query_type query_type)
 
 void Item_func_elt::fix_length_and_dec()
 {
-  max_length=0;
+  uint32 char_length= 0;
   decimals=0;
 
   if (agg_arg_charsets_for_string_result(collation, args + 1, arg_count - 1))
@@ -2383,9 +2364,10 @@ void Item_func_elt::fix_length_and_dec()
 
   for (uint i= 1 ; i < arg_count ; i++)
   {
-    set_if_bigger(max_length,args[i]->max_length);
+    set_if_bigger(char_length, args[i]->max_char_length());
     set_if_bigger(decimals,args[i]->decimals);
   }
+  fix_char_length(char_length);
   maybe_null=1;					// NULL if wrong first arg
 }
 
@@ -2443,14 +2425,14 @@ void Item_func_make_set::split_sum_func(THD *thd, Item **ref_pointer_array,
 
 void Item_func_make_set::fix_length_and_dec()
 {
-  max_length=arg_count-1;
+  uint32 char_length= arg_count - 1; /* Separators */
 
   if (agg_arg_charsets_for_string_result(collation, args, arg_count))
     return;
   
   for (uint i=0 ; i < arg_count ; i++)
-    max_length+=args[i]->max_length;
+    char_length+= args[i]->max_char_length();
-
+  fix_char_length(char_length);
   used_tables_cache|=	  item->used_tables();
   not_null_tables_cache&= item->not_null_tables();
   const_item_cache&=	  item->const_item();
@@ -2616,6 +2598,7 @@ inline String* alloc_buffer(String *res,String *str,String *tmp_value,
 void Item_func_repeat::fix_length_and_dec()
 {
   agg_arg_charsets_for_string_result(collation, args, 1);
+  DBUG_ASSERT(collation.collation != NULL);
   if (args[1]->const_item())
   {
     /* must be longlong to avoid truncation */
@@ -2626,13 +2609,8 @@ void Item_func_repeat::fix_length_and_dec()
     if (count > INT_MAX32)
       count= INT_MAX32;
 
-    ulonglong max_result_length= (ulonglong) args[0]->max_length * count;
+    ulonglong char_length= (ulonglong) args[0]->max_char_length() * count;
-    if (max_result_length >= MAX_BLOB_WIDTH)
+    fix_char_length_ulonglong(char_length);
-    {
-      max_result_length= MAX_BLOB_WIDTH;
-      maybe_null= 1;
-    }
-    max_length= (ulong) max_result_length;
   }
   else
   {
@@ -2703,26 +2681,13 @@ void Item_func_rpad::fix_length_and_dec()
     return;
   if (args[1]->const_item())
   {
-    ulonglong length= 0;
+    ulonglong char_length= (ulonglong) args[1]->val_int();
-
+    DBUG_ASSERT(collation.collation->mbmaxlen > 0);
-    if (collation.collation->mbmaxlen > 0)
+    /* Assumes that the maximum length of a String is < INT_MAX32. */
-    {
+    /* Set here so that rest of code sees out-of-bound value as such. */
-      ulonglong temp= (ulonglong) args[1]->val_int();
+    if (char_length > INT_MAX32)
-
+      char_length= INT_MAX32;
-      /* Assumes that the maximum length of a String is < INT_MAX32. */
+    fix_char_length_ulonglong(char_length);
-      /* Set here so that rest of code sees out-of-bound value as such. */
-      if (temp > INT_MAX32)
-	temp = INT_MAX32;
-
-      length= temp * collation.collation->mbmaxlen;
-    }
-
-    if (length >= MAX_BLOB_WIDTH)
-    {
-      length= MAX_BLOB_WIDTH;
-      maybe_null= 1;
-    }
-    max_length= (ulong) length;
   }
   else
   {
@@ -2806,26 +2771,13 @@ void Item_func_lpad::fix_length_and_dec()
   
   if (args[1]->const_item())
   {
-    ulonglong length= 0;
+    ulonglong char_length= (ulonglong) args[1]->val_int();
-
+    DBUG_ASSERT(collation.collation->mbmaxlen > 0);
-    if (collation.collation->mbmaxlen > 0)
+    /* Assumes that the maximum length of a String is < INT_MAX32. */
-    {
+    /* Set here so that rest of code sees out-of-bound value as such. */
-      ulonglong temp= (ulonglong) args[1]->val_int();
+    if (char_length > INT_MAX32)
-
+      char_length= INT_MAX32;
-      /* Assumes that the maximum length of a String is < INT_MAX32. */
+    fix_char_length_ulonglong(char_length);
-      /* Set here so that rest of code sees out-of-bound value as such. */
-      if (temp > INT_MAX32)
-        temp= INT_MAX32;
-
-      length= temp * collation.collation->mbmaxlen;
-    }
-
-    if (length >= MAX_BLOB_WIDTH)
-    {
-      length= MAX_BLOB_WIDTH;
-      maybe_null= 1;
-    }
-    max_length= (ulong) length;
   }
   else
   {
@@ -3309,8 +3261,8 @@ String* Item_func_export_set::val_str(String* str)
 
 void Item_func_export_set::fix_length_and_dec()
 {
-  uint length=max(args[1]->max_length,args[2]->max_length);
+  uint32 length= max(args[1]->max_char_length(), args[2]->max_char_length());
-  uint sep_length=(arg_count > 3 ? args[3]->max_length : 1);
+  uint32 sep_length= (arg_count > 3 ? args[3]->max_char_length() : 1);
 
   if (agg_arg_charsets_for_string_result(collation,
                                          args + 1, min(4, arg_count) - 1))