diff --git a/mysql-test/r/insert_update.result b/mysql-test/r/insert_update.result
index 4a3e87d9d48..375961292a3 100644
--- a/mysql-test/r/insert_update.result
+++ b/mysql-test/r/insert_update.result
@@ -358,3 +358,38 @@ id	c1	cnt
 5	Y	1
 6	Z	1
 DROP TABLE t1;
+CREATE TABLE t1 (
+id INT AUTO_INCREMENT PRIMARY KEY,
+c1 INT NOT NULL,
+cnt INT DEFAULT 1
+);
+INSERT INTO t1 (id,c1) VALUES (1,10);
+SELECT * FROM t1;
+id	c1	cnt
+1	10	1
+CREATE TABLE t2 (id INT, c1 INT);
+INSERT INTO t2 VALUES (1,NULL), (2,2);
+INSERT INTO t1 (id,c1) SELECT 1,NULL
+ON DUPLICATE KEY UPDATE c1=NULL;
+ERROR 23000: Column 'c1' cannot be null
+SELECT * FROM t1;
+id	c1	cnt
+1	10	1
+INSERT IGNORE INTO t1 (id,c1) SELECT 1,NULL
+ON DUPLICATE KEY UPDATE c1=NULL, cnt=cnt+1;
+Warnings:
+Warning	1263	Column was set to data type implicit default; NULL supplied for NOT NULL column 'c1' at row 1
+Error	1048	Column 'c1' cannot be null
+SELECT * FROM t1;
+id	c1	cnt
+1	0	2
+INSERT IGNORE INTO t1 (id,c1) SELECT * FROM t2
+ON DUPLICATE KEY UPDATE c1=NULL, cnt=cnt+1;
+Warnings:
+Warning	1263	Column was set to data type implicit default; NULL supplied for NOT NULL column 'c1' at row 1
+Error	1048	Column 'c1' cannot be null
+SELECT * FROM t1;
+id	c1	cnt
+1	0	3
+2	2	1
+DROP TABLE t1;
diff --git a/mysql-test/t/insert_update.test b/mysql-test/t/insert_update.test
index 0e199dab4bd..725fbdb25d7 100644
--- a/mysql-test/t/insert_update.test
+++ b/mysql-test/t/insert_update.test
@@ -264,3 +264,29 @@ INSERT  INTO t1 (c1) VALUES ('A'), ('X'), ('Y'), ('Z')
   ON DUPLICATE KEY UPDATE cnt=cnt+1;
 SELECT * FROM t1;
 DROP TABLE t1;
+
+#
+# Bug#28000: INSERT IGNORE ... SELECT ... ON DUPLICATE
+# with erroneous UPDATE: NOT NULL field with NULL value.
+#
+CREATE TABLE t1 (
+  id INT AUTO_INCREMENT PRIMARY KEY,
+  c1 INT NOT NULL,
+  cnt INT DEFAULT 1
+);
+INSERT INTO t1 (id,c1) VALUES (1,10);
+SELECT * FROM t1;
+CREATE TABLE t2 (id INT, c1 INT);
+INSERT INTO t2 VALUES (1,NULL), (2,2);
+--error 1048
+INSERT INTO t1 (id,c1) SELECT 1,NULL
+  ON DUPLICATE KEY UPDATE c1=NULL;
+SELECT * FROM t1;
+INSERT IGNORE INTO t1 (id,c1) SELECT 1,NULL
+  ON DUPLICATE KEY UPDATE c1=NULL, cnt=cnt+1;
+SELECT * FROM t1;
+INSERT IGNORE INTO t1 (id,c1) SELECT * FROM t2
+  ON DUPLICATE KEY UPDATE c1=NULL, cnt=cnt+1;
+SELECT * FROM t1;
+
+DROP TABLE t1;
diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index f1d86224adb..5f54bc2b43b 100644
--- a/sql/sql_insert.cc
+++ b/sql/sql_insert.cc
@@ -1258,7 +1258,8 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
         DBUG_ASSERT(info->update_fields->elements ==
                     info->update_values->elements);
         if (fill_record_n_invoke_before_triggers(thd, *info->update_fields,
-                                                 *info->update_values, 0,
+                                                 *info->update_values,
+                                                 info->ignore,
                                                  table->triggers,
                                                  TRG_EVENT_UPDATE))
           goto before_trg_err;