ctype_utf8.result, ctype_utf8.test:

  New syntax: CHAR(x USING charset)
  Adding test case.
sql_yacc.yy:
  New syntax: CHAR(x USING charset)
  Adding new parser rule.
item_strfunc.h:
  New syntax: CHAR(x USING charset)
  Adding a new constructor.

mysql-test/r/ctype_utf8.result

@@ -1064,46 +1064,56 @@ xxx
 yyy
 DROP TABLE t1;
 set names utf8;
-select hex(char(1));
-hex(char(1))
+select hex(char(1 using utf8));
+hex(char(1 using utf8))
 01
-select char(0xd1,0x8f);
-char(0xd1,0x8f)
+select char(0xd1,0x8f using utf8);
+char(0xd1,0x8f using utf8)
 я
-select char(0xd18f);
-char(0xd18f)
+select char(0xd18f using utf8);
+char(0xd18f using utf8)
 я
-select char(53647);
-char(53647)
+select char(53647 using utf8);
+char(53647 using utf8)
 я
-select char(0xff,0x8f);
-char(0xff,0x8f)
+select char(0xff,0x8f using utf8);
+char(0xff,0x8f using utf8)
 
+Warnings:
+Warning	1300	Invalid utf8 character string: 'FF8F'
 set sql_mode=traditional;
-select char(0xff,0x8f);
-char(0xff,0x8f)
-
-select convert(char(0xff,0x8f) using utf8);
-convert(char(0xff,0x8f) using utf8)
-
-select char(195);
-char(195)
-
-select convert(char(195) using utf8);
-convert(char(195) using utf8)
-
-select char(196);
-char(196)
-
-select convert(char(196) using utf8);
-convert(char(196) using utf8)
-
+select char(0xff,0x8f using utf8);
+char(0xff,0x8f using utf8)
+NULL
+Warnings:
+Error	1300	Invalid utf8 character string: 'FF8F'
+select char(195 using utf8);
+char(195 using utf8)
+NULL
+Warnings:
+Error	1300	Invalid utf8 character string: 'C3'
+select char(196 using utf8);
+char(196 using utf8)
+NULL
+Warnings:
+Error	1300	Invalid utf8 character string: 'C4'
+select char(2557 using utf8);
+char(2557 using utf8)
+NULL
+Warnings:
+Error	1300	Invalid utf8 character string: 'FD'
+select hex(convert(char(2557 using latin1) using utf8));
+hex(convert(char(2557 using latin1) using utf8))
+09C3BD
+select hex(char(195));
+hex(char(195))
+C3
+select hex(char(196));
+hex(char(196))
+C4
 select hex(char(2557));
 hex(char(2557))
 09FD
-select hex(convert(char(2557) using utf8));
-hex(convert(char(2557) using utf8))
-09FD
 set names utf8;
 create table t1 (a char(1)) default character set utf8;
 create table t2 (a char(1)) default character set utf8;

mysql-test/t/ctype_utf8.test

@@ -871,22 +871,32 @@ DROP TABLE t1;
 #
 set names utf8;
 # correct value
-select hex(char(1));
-select char(0xd1,0x8f);
-select char(0xd18f);
-select char(53647);
+select hex(char(1 using utf8));
+select char(0xd1,0x8f using utf8);
+select char(0xd18f using utf8);
+select char(53647 using utf8);
 # incorrect value: return with warning
-select char(0xff,0x8f);
+select char(0xff,0x8f using utf8);
 # incorrect value in strict mode: return NULL with "Error" level warning
 set sql_mode=traditional;
-select char(0xff,0x8f);
-select convert(char(0xff,0x8f) using utf8);
-select char(195);
-select convert(char(195) using utf8);
-select char(196);
-select convert(char(196) using utf8);
+select char(0xff,0x8f using utf8);
+select char(195 using utf8);
+select char(196 using utf8);
+select char(2557 using utf8);
+
+#
+# Check convert + char + using
+#
+select hex(convert(char(2557 using latin1) using utf8));
+
+#
+# char() without USING returns "binary" by default, any argument is ok
+#
+select hex(char(195));
+select hex(char(196));
 select hex(char(2557));
-select hex(convert(char(2557) using utf8));
+
+
 
 #
 # Bug#12891: UNION doesn't return DISTINCT result for multi-byte characters

sql/item_strfunc.h

@@ -480,12 +480,15 @@ public:
 class Item_func_char :public Item_str_func
 {
 public:
-  Item_func_char(List<Item> &list) :Item_str_func(list) {}
+  Item_func_char(List<Item> &list) :Item_str_func(list)
+  { collation.set(&my_charset_bin); }
+  Item_func_char(List<Item> &list, CHARSET_INFO *cs) :Item_str_func(list)
+  { collation.set(cs); }  
   String *val_str(String *);
   void fix_length_and_dec() 
   { 
-    collation.set(&my_charset_bin);
-    maybe_null=0; max_length=arg_count;
+    maybe_null=0;
+    max_length=arg_count * collation.collation->mbmaxlen;
   }
   const char *func_name() const { return "char"; }
 };

sql/sql_yacc.yy

@@ -4536,6 +4536,8 @@ simple_expr:
 	  { $$= new Item_func_atan($3,$5); }
 	| CHAR_SYM '(' expr_list ')'
 	  { $$= new Item_func_char(*$3); }
+	| CHAR_SYM '(' expr_list USING charset_name ')'
+	  { $$= new Item_func_char(*$3, $5); }
 	| CHARSET '(' expr ')'
 	  { $$= new Item_func_charset($3); }
 	| COALESCE '(' expr_list ')'