diff --git a/mysql-test/r/alter_table.result b/mysql-test/r/alter_table.result
index f0edfc9bb59..5a115e9ea99 100644
--- a/mysql-test/r/alter_table.result
+++ b/mysql-test/r/alter_table.result
@@ -996,6 +996,22 @@ SELECT * FROM t1;
 v	b
 abc	5
 DROP TABLE t1;
+create table t1 (a tinytext character set latin1);
+alter table t1 convert to character set utf8;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` text
+) ENGINE=MyISAM DEFAULT CHARSET=utf8
+drop table t1;
+create table t1 (a mediumtext character set latin1);
+alter table t1 convert to character set utf8;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` longtext
+) ENGINE=MyISAM DEFAULT CHARSET=utf8
+drop table t1;
 End of 5.0 tests
 drop table if exists t1, t2, t3;
 create table t1 (i int);
diff --git a/mysql-test/r/type_bit.result b/mysql-test/r/type_bit.result
index 03f3098ea33..b831771d9c5 100644
--- a/mysql-test/r/type_bit.result
+++ b/mysql-test/r/type_bit.result
@@ -723,6 +723,32 @@ CREATE TABLE IF NOT EXISTS t1 (
 f1 bit(2) NOT NULL default b''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
 ERROR 42000: Invalid default value for 'f1'
+create table t1bit7 (a1 bit(7) not null) engine=MyISAM;
+create table t2bit7 (b1 bit(7)) engine=MyISAM;
+insert into t1bit7 values (b'1100000');
+insert into t1bit7 values (b'1100001');
+insert into t1bit7 values (b'1100010');
+insert into t2bit7 values (b'1100001');
+insert into t2bit7 values (b'1100010');
+insert into t2bit7 values (b'1100110');
+select bin(a1) from t1bit7, t2bit7 where t1bit7.a1=t2bit7.b1;
+bin(a1)
+1100001
+1100010
+drop table t1bit7, t2bit7;
+create table t1bit7 (a1 bit(15) not null) engine=MyISAM;
+create table t2bit7 (b1 bit(15)) engine=MyISAM;
+insert into t1bit7 values (b'110000011111111');
+insert into t1bit7 values (b'110000111111111');
+insert into t1bit7 values (b'110001011111111');
+insert into t2bit7 values (b'110000111111111');
+insert into t2bit7 values (b'110001011111111');
+insert into t2bit7 values (b'110011011111111');
+select bin(a1) from t1bit7, t2bit7 where t1bit7.a1=t2bit7.b1;
+bin(a1)
+110000111111111
+110001011111111
+drop table t1bit7, t2bit7;
 End of 5.0 tests
 create table t1(a bit(7));
 insert into t1 values(0x40);
diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test
index 76d57e76491..ae48d5a8736 100644
--- a/mysql-test/t/alter_table.test
+++ b/mysql-test/t/alter_table.test
@@ -751,6 +751,19 @@ ALTER TABLE t1 MODIFY COLUMN v VARCHAR(4);
 SELECT * FROM t1;
 DROP TABLE t1;
 
+
+#
+# Bug#31291 ALTER TABLE CONVERT TO CHARACTER SET does not change some data types
+#
+create table t1 (a tinytext character set latin1);
+alter table t1 convert to character set utf8;
+show create table t1;
+drop table t1;
+create table t1 (a mediumtext character set latin1);
+alter table t1 convert to character set utf8;
+show create table t1;
+drop table t1;
+
 --echo End of 5.0 tests
 
 #
diff --git a/mysql-test/t/type_bit.test b/mysql-test/t/type_bit.test
index 6fb65262e14..dc5120db430 100644
--- a/mysql-test/t/type_bit.test
+++ b/mysql-test/t/type_bit.test
@@ -367,6 +367,36 @@ CREATE TABLE IF NOT EXISTS t1 (
 f1 bit(2) NOT NULL default b''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
 
+
+#
+# Bug#31399 Wrong query result when doing join buffering over BIT fields 
+#
+create table t1bit7 (a1 bit(7) not null) engine=MyISAM; 
+create table t2bit7 (b1 bit(7)) engine=MyISAM; 
+
+insert into t1bit7 values (b'1100000'); 
+insert into t1bit7 values (b'1100001'); 
+insert into t1bit7 values (b'1100010'); 
+insert into t2bit7 values (b'1100001'); 
+insert into t2bit7 values (b'1100010'); 
+insert into t2bit7 values (b'1100110'); 
+
+select bin(a1) from t1bit7, t2bit7 where t1bit7.a1=t2bit7.b1; 
+drop table t1bit7, t2bit7; 
+
+create table t1bit7 (a1 bit(15) not null) engine=MyISAM; 
+create table t2bit7 (b1 bit(15)) engine=MyISAM; 
+
+insert into t1bit7 values (b'110000011111111'); 
+insert into t1bit7 values (b'110000111111111'); 
+insert into t1bit7 values (b'110001011111111'); 
+insert into t2bit7 values (b'110000111111111'); 
+insert into t2bit7 values (b'110001011111111'); 
+insert into t2bit7 values (b'110011011111111'); 
+
+select bin(a1) from t1bit7, t2bit7 where t1bit7.a1=t2bit7.b1; 
+drop table t1bit7, t2bit7; 
+
 --echo End of 5.0 tests
 
 #
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index b1f74d26db3..98ff7605424 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13856,6 +13856,7 @@ join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
   length=0;
   for (i=0 ; i < table_count ; i++)
   {
+    bool have_bit_fields= FALSE;
     uint null_fields=0,used_fields;
     Field **f_ptr,*field;
     MY_BITMAP *read_set= tables[i].table->read_set;
@@ -13870,13 +13871,16 @@ join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
 	length+=field->fill_cache_field(copy);
 	if (copy->blob_field)
 	  (*blob_ptr++)=copy;
-	if (field->maybe_null())
+	if (field->real_maybe_null())
 	  null_fields++;
+        if (field->type() == MYSQL_TYPE_BIT &&
+            ((Field_bit*)field)->bit_len)
+          have_bit_fields= TRUE;    
 	copy++;
       }
     }
     /* Copy null bits from table */
-    if (null_fields && tables[i].table->s->null_fields)
+    if (null_fields || have_bit_fields)
     {						/* must copy null bits */
       copy->str= tables[i].table->null_flags;
       copy->length= tables[i].table->s->null_bytes;
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 16d420441d1..8ce4c0b0a46 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -3111,10 +3111,12 @@ static bool prepare_blob_field(THD *thd, Create_field *sql_field)
     push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE, ER_AUTO_CONVERT,
                  warn_buff);
   }
-    
+
   if ((sql_field->flags & BLOB_FLAG) && sql_field->length)
   {
-    if (sql_field->sql_type == MYSQL_TYPE_BLOB)
+    if (sql_field->sql_type == FIELD_TYPE_BLOB ||
+        sql_field->sql_type == FIELD_TYPE_TINY_BLOB ||
+        sql_field->sql_type == FIELD_TYPE_MEDIUM_BLOB)
     {
       /* The user has given a length to the blob column */
       sql_field->sql_type= get_blob_type_from_length(sql_field->length);