Adding tests for MDEV-9406 CREATE TABLE..SELECT creates different col…

…umns for IFNULL() and equivalent COALESCE,CASE,IF

Recent changes in Type_handler fixed this problem as well.
Adding tests only.

mysql-test/r/func_hybrid_type.result

@@ -3571,5 +3571,40 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 DROP TABLE t1;
 #
+# MDEV-9406 CREATE TABLE..SELECT creates different columns for IFNULL() and equivalent COALESCE,CASE,IF
+#
+CREATE TABLE t1 (a SMALLINT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 AS SELECT
+IFNULL(a,a) AS c1,
+COALESCE(a,a) AS c2,
+CASE WHEN a IS NOT NULL THEN a ELSE a END AS c3,
+IF(a IS NULL,a,a) AS c4 FROM t1;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `c1` smallint(6) DEFAULT NULL,
+  `c2` smallint(6) DEFAULT NULL,
+  `c3` smallint(6) DEFAULT NULL,
+  `c4` smallint(6) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2,t1;
+CREATE TABLE t1 AS SELECT
+connection_id() AS c0,
+IFNULL(connection_id(),connection_id()) AS c1,
+COALESCE(connection_id(), connection_id()) AS c2,
+CASE WHEN 0 THEN connection_id() ELSE connection_id() END AS c3,
+IF(0,connection_id(),connection_id()) AS c4;
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c0` int(10) NOT NULL,
+  `c1` int(10) NOT NULL,
+  `c2` int(10) NOT NULL,
+  `c3` int(10) NOT NULL,
+  `c4` int(10) NOT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+#
 # End of 10.3 tests
 #

mysql-test/t/func_hybrid_type.test

@@ -553,6 +553,28 @@ SELECT * FROM t1;
 SHOW CREATE TABLE t1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-9406 CREATE TABLE..SELECT creates different columns for IFNULL() and equivalent COALESCE,CASE,IF
+--echo #
+CREATE TABLE t1 (a SMALLINT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 AS SELECT
+  IFNULL(a,a) AS c1,
+  COALESCE(a,a) AS c2,
+  CASE WHEN a IS NOT NULL THEN a ELSE a END AS c3,
+  IF(a IS NULL,a,a) AS c4 FROM t1;
+SHOW CREATE TABLE t2;
+DROP TABLE t2,t1;
+
+CREATE TABLE t1 AS SELECT
+  connection_id() AS c0,
+  IFNULL(connection_id(),connection_id()) AS c1,
+  COALESCE(connection_id(), connection_id()) AS c2,
+  CASE WHEN 0 THEN connection_id() ELSE connection_id() END AS c3,
+  IF(0,connection_id(),connection_id()) AS c4;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 10.3 tests
 --echo #