diff --git a/mysql-test/include/ctype_utf8_ilseq.inc b/mysql-test/include/ctype_utf8_ilseq.inc
index 1bb009f2a8b20..3586946659ea4 100644
--- a/mysql-test/include/ctype_utf8_ilseq.inc
+++ b/mysql-test/include/ctype_utf8_ilseq.inc
@@ -14,6 +14,7 @@ SHOW CREATE TABLE t1;
 
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 DELETE FROM t1;
diff --git a/mysql-test/main/compare.result b/mysql-test/main/compare.result
index b4a6b22ba3a18..c465001432601 100644
--- a/mysql-test/main/compare.result
+++ b/mysql-test/main/compare.result
@@ -100,3 +100,23 @@ CREATE TABLE t1(a INT ZEROFILL);
 SELECT 1 FROM t1 WHERE t1.a IN (1, t1.a) AND t1.a=2;
 1
 DROP TABLE t1;
+CREATE TABLE t1 (a char(2), index (a));
+insert into t1 values ("aa"),("bb");
+select * from t1 where a="aa";
+a
+aa
+select * from t1 where a="aaa";
+a
+select * from t1 where a="aa ";
+a
+aa
+select * from t1 where a>="aaa";
+a
+bb
+explain select * from t1 where a="aaa";
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	3	const	1	Using where; Using index
+explain select * from t1 where a="aa ";
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	3	const	1	Using where; Using index
+drop table t1;
diff --git a/mysql-test/main/compare.test b/mysql-test/main/compare.test
index d2b2a7e5523ee..38bda6754d835 100644
--- a/mysql-test/main/compare.test
+++ b/mysql-test/main/compare.test
@@ -94,3 +94,17 @@ DROP TABLE t1;
 CREATE TABLE t1(a INT ZEROFILL);
 SELECT 1 FROM t1 WHERE t1.a IN (1, t1.a) AND t1.a=2;
 DROP TABLE t1;
+
+#
+# Check what happens when comparing to long string
+#
+
+CREATE TABLE t1 (a char(2), index (a));
+insert into t1 values ("aa"),("bb");
+select * from t1 where a="aa";
+select * from t1 where a="aaa";
+select * from t1 where a="aa ";
+select * from t1 where a>="aaa";
+explain select * from t1 where a="aaa";
+explain select * from t1 where a="aa ";
+drop table t1;
diff --git a/mysql-test/main/ctype_uca.result b/mysql-test/main/ctype_uca.result
index 41d2a1149ee00..d4b242d035fde 100644
--- a/mysql-test/main/ctype_uca.result
+++ b/mysql-test/main/ctype_uca.result
@@ -6748,14 +6748,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -6771,22 +6770,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -6829,8 +6820,6 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -6850,14 +6839,10 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 ch
 a
@@ -6877,8 +6862,6 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
@@ -6889,24 +6872,16 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 ALTER TABLE t1 DROP KEY ch;
 # 0xD18F would be a good 2-byte character, 0xD1 is an incomplete sequence
 SET @query=CONCAT('SELECT ch FROM t1 WHERE ch=''a', 0xD1,'''');
@@ -6992,14 +6967,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -7015,22 +6989,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
diff --git a/mysql-test/main/ctype_uca_innodb.result b/mysql-test/main/ctype_uca_innodb.result
index bd6f3b8a21fbb..7c64f17190e05 100644
--- a/mysql-test/main/ctype_uca_innodb.result
+++ b/mysql-test/main/ctype_uca_innodb.result
@@ -23,14 +23,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -46,22 +45,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -104,8 +95,6 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -125,14 +114,10 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 ch
 a
@@ -152,8 +137,6 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
@@ -164,24 +147,16 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 ALTER TABLE t1 DROP KEY ch;
 # 0xD18F would be a good 2-byte character, 0xD1 is an incomplete sequence
 SET @query=CONCAT('SELECT ch FROM t1 WHERE ch=''a', 0xD1,'''');
diff --git a/mysql-test/main/ctype_utf8.result b/mysql-test/main/ctype_utf8.result
index a1f5537a8d74d..45d9d1d7e5ad0 100644
--- a/mysql-test/main/ctype_utf8.result
+++ b/mysql-test/main/ctype_utf8.result
@@ -5467,14 +5467,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -5490,22 +5489,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -5548,8 +5539,6 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -5569,14 +5558,10 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 ch
 a
@@ -5596,8 +5581,6 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
@@ -5608,24 +5591,16 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 ALTER TABLE t1 DROP KEY ch;
 # 0xD18F would be a good 2-byte character, 0xD1 is an incomplete sequence
 SET @query=CONCAT('SELECT ch FROM t1 WHERE ch=''a', 0xD1,'''');
@@ -5711,14 +5686,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -5734,22 +5708,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -5792,8 +5758,6 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
@@ -5813,14 +5777,10 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch<'a𝌆b' ORDER BY ch;
 ch
 a
@@ -5840,8 +5800,6 @@ ab
 az
 aЀ
 aր
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
@@ -5852,24 +5810,16 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ch	ch	183	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch>'a𝌆b' ORDER BY ch;
 ch
 z
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 ALTER TABLE t1 DROP KEY ch;
 # 0xD18F would be a good 2-byte character, 0xD1 is an incomplete sequence
 SET @query=CONCAT('SELECT ch FROM t1 WHERE ch=''a', 0xD1,'''');
@@ -5955,14 +5905,13 @@ t1	CREATE TABLE `t1` (
 INSERT INTO t1 (ch) VALUES ('admin'),('admin1');
 SELECT ch FROM t1 WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
+EXPLAIN SELECT ch FROM t1 WHERE ch='admin𝌆';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch='admin𝌆';
 ch
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='admin𝌆';
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 DELETE FROM t1;
 INSERT INTO t1 (ch) VALUES ('a'), ('a?'), ('a??'), ('a???'), ('a????');
 INSERT INTO t1 (ch) VALUES ('ab'),('a?b'),('a??b'),('a???b'),('a????b');
@@ -5978,22 +5927,14 @@ EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86' for column `test`.`t1`.`ch` at row 1
 EXPLAIN
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	#	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 FORCE KEY (ch) WHERE ch='a𝌆b' ORDER BY ch;
 ch
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9D\x8C\x86b' for column `test`.`t1`.`ch` at row 1
 SELECT ch FROM t1 IGNORE KEY (ch) WHERE ch<'a𝌆' ORDER BY ch;
 ch
 a
diff --git a/mysql-test/main/processlist.result b/mysql-test/main/processlist.result
index ab518d961ef3c..4be643c179045 100644
--- a/mysql-test/main/processlist.result
+++ b/mysql-test/main/processlist.result
@@ -36,10 +36,6 @@ SELECT INFO, INFO_BINARY, 'xxx😎yyy' AS utf8mb4_string FROM INFORMATION_SCHEMA
 INFO	SELECT INFO, INFO_BINARY, 'xxx????yyy' AS utf8mb4_string FROM INFORMATION_SCHEMA.PROCESSLIST WHERE INFO LIKE '%xxx%yyy%'
 INFO_BINARY	SELECT INFO, INFO_BINARY, 'xxx😎yyy' AS utf8mb4_string FROM INFORMATION_SCHEMA.PROCESSLIST WHERE INFO LIKE '%xxx%yyy%'
 utf8mb4_string	xxx😎yyy
-Warnings:
-Level	Warning
-Code	1366
-Message	Incorrect string value: '\xF0\x9F\x98\x8Eyy...' for column `information_schema`.`(temporary)`.`INFO` at row 1
 #
 # End of 10.1 tests
 #
diff --git a/mysql-test/main/range.result b/mysql-test/main/range.result
index 3ad577c79e9b7..aa322a59274c9 100644
--- a/mysql-test/main/range.result
+++ b/mysql-test/main/range.result
@@ -2056,23 +2056,15 @@ explain
 SELECT * FROM t1 WHERE fd='😁';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 SELECT * FROM t1 WHERE fd='😁';
 id	fd
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 # The following must not use range access:
 explain select count(*) from t1 where fd <'😁';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ix_fd	ix_fd	63	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 select count(*) from t1 where fd <'😁';
 count(*)
 40960
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 select count(*) from t1 ignore index (ix_fd) where fd <'😁';
 count(*)
 40960
@@ -2293,8 +2285,6 @@ INSERT INTO t1 VALUES ('a'),('b'),('c'),('d'),('e');
 EXPLAIN SELECT * FROM t1 WHERE a<=>'😎';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x8E' for column `test`.`t1`.`a` at row 1
 DROP TABLE t1;
 #
 # MDEV-10185: Assertion `tree1->keys[key_no] && tree2->keys[key_no]' failed in 
diff --git a/mysql-test/main/range_mrr_icp.result b/mysql-test/main/range_mrr_icp.result
index 05b2b700d4737..4af7dd77d7e18 100644
--- a/mysql-test/main/range_mrr_icp.result
+++ b/mysql-test/main/range_mrr_icp.result
@@ -2058,23 +2058,15 @@ explain
 SELECT * FROM t1 WHERE fd='😁';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 SELECT * FROM t1 WHERE fd='😁';
 id	fd
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 # The following must not use range access:
 explain select count(*) from t1 where fd <'😁';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	ix_fd	ix_fd	63	NULL	#	Using where; Using index
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 select count(*) from t1 where fd <'😁';
 count(*)
 40960
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x81' for column `test`.`t1`.`fd` at row 1
 select count(*) from t1 ignore index (ix_fd) where fd <'😁';
 count(*)
 40960
@@ -2295,8 +2287,6 @@ INSERT INTO t1 VALUES ('a'),('b'),('c'),('d'),('e');
 EXPLAIN SELECT * FROM t1 WHERE a<=>'😎';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1366	Incorrect string value: '\xF0\x9F\x98\x8E' for column `test`.`t1`.`a` at row 1
 DROP TABLE t1;
 #
 # MDEV-10185: Assertion `tree1->keys[key_no] && tree2->keys[key_no]' failed in 
diff --git a/sql/field.cc b/sql/field.cc
index 0d9797143fac0..14d7843350373 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -71,7 +71,7 @@ const char field_separator=',';
                   ptr < table->record[0] + table->s->reclength))))
 
 #define ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED                   \
-  DBUG_ASSERT(is_stat_field || !table ||                             \
+  DBUG_ASSERT(!table ||                             \
               (!table->write_set ||                                  \
                bitmap_is_set(table->write_set, field_index) ||       \
                (!(ptr >= table->record[0] &&                         \
@@ -2406,8 +2406,7 @@ Field *Field::clone(MEM_ROOT *root, TABLE *new_table)
 
 
 
-Field *Field::clone(MEM_ROOT *root, TABLE *new_table, my_ptrdiff_t diff,
-                    bool stat_flag)
+Field *Field::clone(MEM_ROOT *root, TABLE *new_table, my_ptrdiff_t diff)
 {
   Field *tmp;
   if ((tmp= (Field*) memdup_root(root,(char*) this,size_of())))
@@ -2415,7 +2414,6 @@ Field *Field::clone(MEM_ROOT *root, TABLE *new_table, my_ptrdiff_t diff,
     tmp->init(new_table);
     tmp->move_field_offset(diff);
   }
-  tmp->is_stat_field= stat_flag;
   return tmp;
 }
 
@@ -2853,7 +2851,7 @@ int Field_decimal::store(const char *from_arg, size_t len, CHARSET_INFO *cs)
   
   /*
     Write digits of the frac_% parts ;
-    Depending on get_thd()->count_cutted_fields, we may also want
+    Depending on get_thd()->count_cuted_fields, we may also want
     to know if some non-zero tail of these parts will
     be truncated (for example, 0.002->0.00 will generate a warning,
     while 0.000->0.00 will not)
@@ -6991,7 +6989,8 @@ Field_longstr::check_string_copy_error(const String_copier *copier,
   if (likely(!(pos= copier->most_important_error_pos())))
     return FALSE;
 
-  if (!is_stat_field)
+  /* Ignore errors from internal expressions */
+  if (get_thd()->count_cuted_fields > CHECK_FIELD_EXPRESSION)
   {
     convert_to_printable(tmp, sizeof(tmp), pos, (end - pos), cs, 6);
     set_warning_truncated_wrong_value("string", tmp);
@@ -7024,8 +7023,9 @@ int
 Field_longstr::report_if_important_data(const char *pstr, const char *end,
                                         bool count_spaces)
 {
-  THD *thd= get_thd();
-  if ((pstr < end) && thd->count_cuted_fields > CHECK_FIELD_EXPRESSION)
+  THD *thd;
+  if ((pstr < end) &&
+      (thd= get_thd())->count_cuted_fields > CHECK_FIELD_EXPRESSION)
   {
     if (test_if_important_data(field_charset, pstr, end))
     {
@@ -7036,7 +7036,8 @@ Field_longstr::report_if_important_data(const char *pstr, const char *end,
       return 2;
     }
     else if (count_spaces)
-    { /* If we lost only spaces then produce a NOTE, not a WARNING */
+    {
+      /* If we lost only spaces then produce a NOTE, not a WARNING */
       set_note(WARN_DATA_TRUNCATED, 1);
       return 2;
     }
@@ -11381,13 +11382,17 @@ void Field::set_warning_truncated_wrong_value(const char *type_arg,
                                               const char *value)
 {
   THD *thd= get_thd();
-  const char *db_name= table->s->db.str;
-  const char *table_name= table->s->table_name.str;
+  const char *db_name;
+  const char *table_name;
+  /*
+    table has in the past been 0 in case of wrong calls when processing
+    statistics tables. Let's protect against that.
+  */
+  DBUG_ASSERT(table);
 
-  if (!db_name)
-    db_name= "";
-  if (!table_name)
-    table_name= "";
+  db_name= (table && table->s->db.str) ? table->s->db.str : "";
+  table_name= ((table && table->s->table_name.str) ? table->s->table_name.str :
+	       "");
 
   push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                       ER_TRUNCATED_WRONG_VALUE_FOR_FIELD,
diff --git a/sql/field.h b/sql/field.h
index c2d1d241e27ab..053236133d066 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -1253,8 +1253,7 @@ class Field: public Value_source
                                uchar *new_ptr, uint32 length,
                                uchar *new_null_ptr, uint new_null_bit);
   Field *clone(MEM_ROOT *mem_root, TABLE *new_table);
-  Field *clone(MEM_ROOT *mem_root, TABLE *new_table, my_ptrdiff_t diff,
-               bool stat_flag= FALSE);
+  Field *clone(MEM_ROOT *mem_root, TABLE *new_table, my_ptrdiff_t diff);
   Field *clone(MEM_ROOT *mem_root, my_ptrdiff_t diff);
   inline void move_field(uchar *ptr_arg,uchar *null_ptr_arg,uchar null_bit_arg)
   {
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc
index 8d1342773f716..5e0275fa65d95 100644
--- a/sql/sql_statistics.cc
+++ b/sql/sql_statistics.cc
@@ -1042,7 +1042,9 @@ class Column_stat: public Stat_table
   {
     char buff[MAX_FIELD_WIDTH];
     String val(buff, sizeof(buff), &my_charset_bin);
+    my_bitmap_map *old_map;
 
+    old_map= dbug_tmp_use_all_columns(stat_table, stat_table->read_set);
     for (uint i= COLUMN_STAT_MIN_VALUE; i <= COLUMN_STAT_HISTOGRAM; i++)
     {  
       Field *stat_field= stat_table->field[i];
@@ -1100,6 +1102,7 @@ class Column_stat: public Stat_table
         }
       }
     }
+    dbug_tmp_restore_column_map(stat_table->read_set, old_map);
   }
 
 
@@ -1973,7 +1976,7 @@ void create_min_max_statistical_fields_for_table(TABLE *table)
         my_ptrdiff_t diff= record-table->record[0];
         if (!bitmap_is_set(table->read_set, table_field->field_index))
           continue; 
-        if (!(fld= table_field->clone(&table->mem_root, table, diff, TRUE)))
+        if (!(fld= table_field->clone(&table->mem_root, table, diff)))
           continue;
         if (i == 0)
           table_field->collected_stats->min_value= fld;
@@ -2984,9 +2987,12 @@ int read_statistics_for_table(THD *thd, TABLE *table, TABLE_LIST *stat_tables)
   KEY *key_info, *key_info_end;
   TABLE_SHARE *table_share= table->s;
   Table_statistics *read_stats= table_share->stats_cb.table_stats;
-
+  enum_check_fields old_check_level= thd->count_cuted_fields;
   DBUG_ENTER("read_statistics_for_table");
 
+  /* Don't write warnings for internal field conversions */
+  thd->count_cuted_fields= CHECK_FIELD_IGNORE;
+
   /* Read statistics from the statistical table table_stats */
   stat_table= stat_tables[TABLE_STAT].table;
   Table_stat table_stat(stat_table, table);
@@ -3067,6 +3073,7 @@ int read_statistics_for_table(THD *thd, TABLE *table, TABLE_LIST *stat_tables)
   }
 
   table->stats_is_read= TRUE;
+  thd->count_cuted_fields= old_check_level;
 
   DBUG_RETURN(0);
 }