diff --git a/mysql-test/r/join_cache.result b/mysql-test/r/join_cache.result
index 36152af7898..4973288cd9f 100644
--- a/mysql-test/r/join_cache.result
+++ b/mysql-test/r/join_cache.result
@@ -6004,4 +6004,56 @@ a1	a2	b2	a3	b3
 SET SESSION optimizer_switch = 'outer_join_with_cache=off';
 SET SESSION join_cache_level = DEFAULT;
 DROP TABLE t1,t2,t3;
+#
+# Bug #675922: incremental buffer for BKA with access from previous
+#      buffers from non-nullable columns whose values may be null
+#
+CREATE TABLE t1 (a1 varchar(32)) ;
+INSERT INTO t1 VALUES ('s'),('k');
+CREATE TABLE t2 (a2 int PRIMARY KEY, b2 varchar(32)) ;
+INSERT INTO t2 VALUES (7,'s');
+CREATE TABLE t3 (a3 int PRIMARY KEY, b3 varchar(32)) ;
+INSERT INTO t3 VALUES (7,'s');
+CREATE TABLE t4 (a4 int) ;
+INSERT INTO t4 VALUES (9);
+CREATE TABLE t5(a5 int PRIMARY KEY, b5 int) ;
+INSERT INTO t5 VALUES (7,0);
+SET SESSION optimizer_switch = 'outer_join_with_cache=on';
+SET SESSION join_cache_level = 0;
+EXPLAIN
+SELECT t4.a4, t5.b5 
+FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	ALL	PRIMARY	NULL	NULL	NULL	1	Using where
+1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
+1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where
+1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where
+SELECT t4.a4, t5.b5 
+FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+a4	b5
+9	0
+9	NULL
+SET SESSION join_cache_level = 6;
+EXPLAIN
+SELECT t4.a4, t5.b5 
+FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	ALL	PRIMARY	NULL	NULL	NULL	1	Using where
+1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
+1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BKA join)
+SELECT t4.a4, t5.b5 
+FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+a4	b5
+9	0
+9	NULL
+SET SESSION optimizer_switch = 'outer_join_with_cache=off';
+SET SESSION join_cache_level = DEFAULT;
+DROP TABLE t1,t2,t3,t4,t5;
 set @@optimizer_switch=@save_optimizer_switch;
diff --git a/mysql-test/t/join_cache.test b/mysql-test/t/join_cache.test
index bb0d1b56a3d..1905297b25b 100644
--- a/mysql-test/t/join_cache.test
+++ b/mysql-test/t/join_cache.test
@@ -2655,5 +2655,50 @@ SET SESSION join_cache_level = DEFAULT;
 
 DROP TABLE t1,t2,t3;
 
+--echo #
+--echo # Bug #675922: incremental buffer for BKA with access from previous
+--echo #      buffers from non-nullable columns whose values may be null
+--echo #
+
+CREATE TABLE t1 (a1 varchar(32)) ;
+INSERT INTO t1 VALUES ('s'),('k');
+
+CREATE TABLE t2 (a2 int PRIMARY KEY, b2 varchar(32)) ;
+INSERT INTO t2 VALUES (7,'s');
+
+CREATE TABLE t3 (a3 int PRIMARY KEY, b3 varchar(32)) ;
+INSERT INTO t3 VALUES (7,'s');
+
+CREATE TABLE t4 (a4 int) ;
+INSERT INTO t4 VALUES (9);
+
+CREATE TABLE t5(a5 int PRIMARY KEY, b5 int) ;
+INSERT INTO t5 VALUES (7,0);
+
+SET SESSION optimizer_switch = 'outer_join_with_cache=on';
+
+SET SESSION join_cache_level = 0;
+EXPLAIN
+SELECT t4.a4, t5.b5 
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT t4.a4, t5.b5 
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+SET SESSION join_cache_level = 6;
+EXPLAIN
+SELECT t4.a4, t5.b5 
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT t4.a4, t5.b5 
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+SET SESSION optimizer_switch = 'outer_join_with_cache=off';
+SET SESSION join_cache_level = DEFAULT;
+
+DROP TABLE t1,t2,t3,t4,t5;
+
 # this must be the last command in the file
 set @@optimizer_switch=@save_optimizer_switch;
diff --git a/sql/sql_join_cache.cc b/sql/sql_join_cache.cc
index c3f2dfa5541..713d6f9e93f 100644
--- a/sql/sql_join_cache.cc
+++ b/sql/sql_join_cache.cc
@@ -1776,7 +1776,13 @@ uint JOIN_CACHE::read_record_field(CACHE_FIELD *copy, bool blob_in_rec_buff)
     If the value of *len is 0 then the function sets it to the total
     length of the record fields including possible trailing offset
     values. Otherwise *len is supposed to provide this value that
-    has been obtained earlier.  
+    has been obtained earlier. 
+
+  NOTE
+    If the value of the referenced field is null then the offset
+    for the value is set to 0. If the value of a field can be null
+    then the value of flag_fields is always positive. So the offset
+    for any non-null value cannot be 0 in this case. 
 
   RETURN VALUE
     TRUE   'copy' points to a data descriptor of this join cache
@@ -1805,14 +1811,21 @@ bool JOIN_CACHE::read_referenced_field(CACHE_FIELD *copy,
                          size_of_fld_ofs*
                          (referenced_fields+1-copy->referenced_field_no));  
   bool is_null= FALSE;
+  Field *field= copy->field;
   if (offset == 0 && flag_fields)
     is_null= TRUE;
   if (is_null)
-    copy->field->set_null();
+  {
+    field->set_null();
+    if (!field->real_maybe_null())
+      field->table->null_row= 1;
+  }
   else
   {
     uchar *save_pos= pos;
-    copy->field->set_notnull(); 
+    field->set_notnull(); 
+    if (!field->real_maybe_null())
+      field->table->null_row= 0;
     pos= rec_ptr+offset;
     read_record_field(copy, blob_data_is_in_rec_buff(rec_ptr));
     pos= save_pos;