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USE test;
#
# MDEV-14013 : sql_mode=EMPTY_STRING_IS_NULL
#
set @mode='EMPTY_STRING_IS_NULL';
SET SESSION character_set_connection=latin2;
SET SESSION character_set_client=cp1250;
#
# Test litteral
#
SET sql_mode=@mode;
select @@sql_mode;
@@sql_mode
EMPTY_STRING_IS_NULL
SELECT '',CHARSET(''), null, CHARSET(null), CAST(null as char(10)), CHARSET(CAST(null as char(10))), 'x', CHARSET('x');
NULL CHARSET('') NULL CHARSET(null) CAST(null as char(10)) CHARSET(CAST(null as char(10))) x CHARSET('x')
NULL latin2 NULL binary NULL latin2 x latin2
SELECT CHARSET(NULLIF('','')),NULLIF('','');
CHARSET(NULLIF('','')) NULLIF('','')
latin2 NULL
SET sql_mode=default;
SELECT '',CHARSET(''), null, CHARSET(null), CAST(null as char(10)), CHARSET(CAST(null as char(10))), 'x', CHARSET('x');
CHARSET('') NULL CHARSET(null) CAST(null as char(10)) CHARSET(CAST(null as char(10))) x CHARSET('x')
latin2 NULL binary NULL latin2 x latin2
SELECT CHARSET(NULLIF('','')),NULLIF('','');
CHARSET(NULLIF('','')) NULLIF('','')
latin2 NULL
#
# Test NCHAR litteral
#
SET sql_mode=@mode;
SELECT N'',CHARSET(N''), N'x', CHARSET(N'x');
NULL CHARSET(N'') x CHARSET(N'x')
NULL utf8 x utf8
SELECT CHARSET(NULLIF(N'',N'')),NULLIF(N'',N'');
CHARSET(NULLIF(N'',N'')) NULLIF(N'',N'')
utf8 NULL
SET sql_mode=default;
SELECT N'',CHARSET(N''), N'x', CHARSET(N'x');
CHARSET(N'') x CHARSET(N'x')
utf8 x utf8
SELECT CHARSET(NULLIF(N'',N'')),NULLIF(N'',N'');
CHARSET(NULLIF(N'',N'')) NULLIF(N'',N'')
utf8 NULL
#
# Test CHARSET prefix litteral
#
SET sql_mode=@mode;
SELECT _cp1250 '',CHARSET(_cp1250 ''), _cp1250 'x', CHARSET(_cp1250 'x');
NULL CHARSET(_cp1250 '') x CHARSET(_cp1250 'x')
NULL cp1250 x cp1250
SELECT CHARSET(NULLIF(_cp1250 '',_cp1250 '')),NULLIF(_cp1250 '',_cp1250 '');
CHARSET(NULLIF(_cp1250 '',_cp1250 '')) NULLIF(_cp1250 '',_cp1250 '')
cp1250 NULL
SET sql_mode=default;
SELECT _cp1250 '',CHARSET(_cp1250 ''), _cp1250 'x', CHARSET(_cp1250 'x');
CHARSET(_cp1250 '') x CHARSET(_cp1250 'x')
cp1250 x cp1250
SELECT CHARSET(NULLIF(_cp1250 '',_cp1250 '')),NULLIF(_cp1250 '',_cp1250 '');
CHARSET(NULLIF(_cp1250 '',_cp1250 '')) NULLIF(_cp1250 '',_cp1250 '')
cp1250 NULL
SET sql_mode=@mode;
#
# Test litteral concat
#
SELECT 'a' 'b';
a
ab
SELECT 'a' '';
a
a
SELECT '' 'b';
b
b
SELECT '' '';
NULL
NULL
SELECT '' 'b' 'c';
b
bc
SELECT '' '' 'c';
c
c
SELECT 'a' '' 'c';
a
ac
SELECT 'a' '' '';
a
a
SELECT '' '' '';
NULL
NULL
SELECT '' '' '',CHARSET('' '' '');
NULL CHARSET('' '' '')
NULL latin2
SELECT _latin1'' '' '',CHARSET(_latin1'' '' '');
NULL CHARSET(_latin1'' '' '')
NULL latin1
SELECT N'' '' '',CHARSET(N'' '' '');
NULL CHARSET(N'' '' '')
NULL utf8
#
# UNION - implicit group by
#
SELECT 1, null
UNION
SELECT 1 , ''
ORDER BY 1;
1 NULL
1 NULL
SELECT 1, null
UNION
SELECT 1 , N''
ORDER BY 1;
1 NULL
1 NULL
SELECT 1, null
UNION
SELECT 1 , _cp1250 ''
ORDER BY 1;
1 NULL
1 NULL
SELECT NULLIF(_cp1250 '',_cp1250 '')
UNION
SELECT NULLIF(N'',N'');
NULLIF(_cp1250 '',_cp1250 '')
NULL
SELECT 1 , _latin2 ''
UNION
SELECT 1 , _cp1250 '';
ERROR HY000: Illegal mix of collations (latin2_general_ci,IGNORABLE) and (cp1250_general_ci,IGNORABLE) for operation 'UNION'
SELECT 1, null
UNION
SELECT 1 , ''
UNION
SELECT 1 , N'';
1 NULL
1 NULL
CREATE TABLE t1 (c1 INT,c2 VARCHAR(10));
INSERT INTO t1 VALUES (1,'one');
INSERT INTO t1 VALUES (1,'');
INSERT INTO t1 VALUES (1,null);
#
# Test in a view
#
CREATE VIEW v1
AS SELECT c1, c2
FROM t1
UNION
SELECT c1 , ''
FROM t1
ORDER BY 1,2;
SELECT * FROM v1;
c1 c2
1 NULL
1 one
SHOW CREATE VIEW v1;
View Create View character_set_client collation_connection
v1 CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`c1` AS `c1`,`t1`.`c2` AS `c2` from `t1` union select `t1`.`c1` AS `c1`,NULL AS `NULL` from `t1` order by 1,2 cp1250 latin2_general_ci
DROP VIEW v1;
DROP TABLE t1;
EXPLAIN EXTENDED SELECT '';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select NULL AS `NULL`
EXPLAIN EXTENDED SELECT _latin1'';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select NULL AS `NULL`
EXPLAIN EXTENDED SELECT N'';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select NULL AS `NULL`
EXPLAIN EXTENDED SELECT '' '';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select NULL AS `NULL`
#
# MDEV-20763 Table corruption or Assertion `btr_validate_index(index, 0, false)' failed in row_upd_sec_index_entry with virtual column and EMPTY_STRING_IS_NULL SQL mode
#
create table t1 (a int, b binary(1) generated always as (''), key(a,b));
insert into t1 (a) values (1);
set sql_mode= default;
flush tables;
update t1 set a = 2;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL,
`b` binary(1) GENERATED ALWAYS AS (NULL) VIRTUAL,
KEY `a` (`a`,`b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
create table t1 (a int, b binary(1) generated always as (''), key(a,b));
insert into t1 (a) values (1);
set sql_mode= 'empty_string_is_null';
flush tables;
update t1 set a = 2;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL,
`b` binary(1) GENERATED ALWAYS AS ('') VIRTUAL,
KEY `a` (`a`,`b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
drop table t1;
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