Commit a78629c4 authored by Ramil Kalimullin's avatar Ramil Kalimullin
Browse files

Fix for bug#36772: When using UTF8, CONVERT with GROUP BY 

returns truncated results

Problem: performig conversion from {INT, DECIMAL, REAL} to CHAR
we incorrectly set its max length in some cases that may lead
to truncated results returned.

Fix: properly set CONVERT({INT, DECIMAL, REAL}, CHAR) result's
max length.
parent 240d0633

mysql-test/r/ctype_utf8.result

+32 −0
Original line number Diff line number Diff line
@@ -1813,3 +1813,35 @@ select hex(_utf8 B'001111111111'); 
ERROR HY000: Invalid utf8 character string: 'FF'

select (_utf8 X'616263FF');

ERROR HY000: Invalid utf8 character string: 'FF'

CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL);

INSERT INTO t1 VALUES (70000, 1092), (70001, 1085), (70002, 1065);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

CONVERT(a, CHAR)	CONVERT(b, CHAR)

70002	1065

70001	1085

70000	1092

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1;

CONVERT(a, CHAR)	CONVERT(b, CHAR)

70000	1092

70001	1085

70002	1065

ALTER TABLE t1 ADD UNIQUE (b);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

CONVERT(a, CHAR)	CONVERT(b, CHAR)

70002	1065

70001	1085

70000	1092

DROP INDEX b ON t1;

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

CONVERT(a, CHAR)	CONVERT(b, CHAR)

70002	1065

70001	1085

70000	1092

ALTER TABLE t1 ADD INDEX (b);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) from t1 GROUP BY b;

CONVERT(a, CHAR)	CONVERT(b, CHAR)

70002	1065

70001	1085

70000	1092

DROP TABLE t1;

End of 5.0 tests

mysql-test/t/ctype_utf8.test

+17 −0
Original line number Diff line number Diff line
@@ -1437,3 +1437,20 @@ select hex(_utf8 X'616263FF'); 
select hex(_utf8 B'001111111111');

--error ER_INVALID_CHARACTER_STRING

select (_utf8 X'616263FF');



#

# Bug #36772: When using UTF8, CONVERT with GROUP BY returns truncated results

#

CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL);

INSERT INTO t1 VALUES (70000, 1092), (70001, 1085), (70002, 1065);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1;

ALTER TABLE t1 ADD UNIQUE (b);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

DROP INDEX b ON t1;

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) FROM t1 GROUP BY b;

ALTER TABLE t1 ADD INDEX (b);

SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) from t1 GROUP BY b;

DROP TABLE t1;



--echo End of 5.0 tests

sql/item_timefunc.cc

+8 −5
Original line number Diff line number Diff line
@@ -2550,6 +2550,8 @@ void Item_char_typecast::fix_length_and_dec() 
       and thus avoid unnecessary character set conversion.

     - If the argument is not a number, then from_cs is set to

       the argument's charset.



       Note (TODO): we could use repertoire technique here.

  */

  from_cs= (args[0]->result_type() == INT_RESULT || 

            args[0]->result_type() == DECIMAL_RESULT ||
@@ -2557,12 +2559,13 @@ void Item_char_typecast::fix_length_and_dec() 
           (cast_cs->mbminlen == 1 ? cast_cs : &my_charset_latin1) :

           args[0]->collation.collation;

  charset_conversion= (cast_cs->mbmaxlen > 1) ||

                      !my_charset_same(from_cs, cast_cs) &&

                      (!my_charset_same(from_cs, cast_cs) &&

                       from_cs != &my_charset_bin &&

                      cast_cs != &my_charset_bin;

                       cast_cs != &my_charset_bin);

  collation.set(cast_cs, DERIVATION_IMPLICIT);

  char_length= (cast_length >= 0) ? cast_length : 

	       args[0]->max_length/from_cs->mbmaxlen;

  char_length= (cast_length >= 0) ?

                 cast_length :

                 args[0]->max_length / args[0]->collation.collation->mbmaxlen;

  max_length= char_length * cast_cs->mbmaxlen;

}