drop table if exists t1;
select null,\N,isnull(null),isnull(1/0),isnull(1/0 = null),ifnull(null,1),ifnull(null,"TRUE"),ifnull("TRUE","ERROR"),1/0 is null,1 is not null;
NULL	NULL	isnull(null)	isnull(1/0)	isnull(1/0 = null)	ifnull(null,1)	ifnull(null,"TRUE")	ifnull("TRUE","ERROR")	1/0 is null	1 is not null
NULL	NULL	1	1	1	1	TRUE	TRUE	1	1
explain extended select null,\N,isnull(null),isnull(1/0),isnull(1/0 = null),ifnull(null,1),ifnull(null,"TRUE"),ifnull("TRUE","ERROR"),1/0 is null,1 is not null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select NULL AS `NULL`,NULL AS `NULL`,isnull(NULL) AS `isnull(null)`,isnull((1 / 0)) AS `isnull(1/0)`,isnull(((1 / 0) = NULL)) AS `isnull(1/0 = null)`,ifnull(NULL,1) AS `ifnull(null,1)`,ifnull(NULL,_latin1'TRUE') AS `ifnull(null,"TRUE")`,ifnull(_latin1'TRUE',_latin1'ERROR') AS `ifnull("TRUE","ERROR")`,isnull((1 / 0)) AS `1/0 is null`,(1 is not null) AS `1 is not null`
select 1 | NULL,1 & NULL,1+NULL,1-NULL;
1 | NULL	1 & NULL	1+NULL	1-NULL
NULL	NULL	NULL	NULL
select NULL=NULL,NULL<>NULL,IFNULL(NULL,1.1)+0,IFNULL(NULL,1) | 0;
NULL=NULL	NULL<>NULL	IFNULL(NULL,1.1)+0	IFNULL(NULL,1) | 0
NULL	NULL	1.1	1
select strcmp("a",NULL),(1<NULL)+0.0,NULL regexp "a",null like "a%","a%" like null;
strcmp("a",NULL)	(1<NULL)+0.0	NULL regexp "a"	null like "a%"	"a%" like null
NULL	NULL	NULL	NULL	NULL
select concat("a",NULL),replace(NULL,"a","b"),replace("string","i",NULL),replace("string",NULL,"i"),insert("abc",1,1,NULL),left(NULL,1);
concat("a",NULL)	replace(NULL,"a","b")	replace("string","i",NULL)	replace("string",NULL,"i")	insert("abc",1,1,NULL)	left(NULL,1)
NULL	NULL	NULL	NULL	NULL	NULL
select repeat("a",0),repeat("ab",5+5),repeat("ab",-1),reverse(NULL);
repeat("a",0)	repeat("ab",5+5)	repeat("ab",-1)	reverse(NULL)
	abababababababababab		NULL
select field(NULL,"a","b","c");
field(NULL,"a","b","c")
0
select 2 between null and 1,2 between 3 AND NULL,NULL between 1 and 2,2 between NULL and 3, 2 between 1 AND null;
2 between null and 1	2 between 3 AND NULL	NULL between 1 and 2	2 between NULL and 3	2 between 1 AND null
0	0	NULL	NULL	NULL
explain extended select 2 between null and 1,2 between 3 AND NULL,NULL between 1 and 2,2 between NULL and 3, 2 between 1 AND null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select (2 between NULL and 1) AS `2 between null and 1`,(2 between 3 and NULL) AS `2 between 3 AND NULL`,(NULL between 1 and 2) AS `NULL between 1 and 2`,(2 between NULL and 3) AS `2 between NULL and 3`,(2 between 1 and NULL) AS `2 between 1 AND null`
SELECT NULL AND NULL, 1 AND NULL, NULL AND 1, NULL OR NULL, 0 OR NULL, NULL OR 0;
NULL AND NULL	1 AND NULL	NULL AND 1	NULL OR NULL	0 OR NULL	NULL OR 0
NULL	NULL	NULL	NULL	NULL	NULL
SELECT (NULL OR NULL) IS NULL;
(NULL OR NULL) IS NULL
1
select NULL AND 0, 0 and NULL;
NULL AND 0	0 and NULL
0	0
select inet_ntoa(null),inet_aton(null),inet_aton("122.256"),inet_aton("122.226."),inet_aton("");
inet_ntoa(null)	inet_aton(null)	inet_aton("122.256")	inet_aton("122.226.")	inet_aton("")
NULL	NULL	NULL	NULL	NULL
explain extended select inet_ntoa(null),inet_aton(null),inet_aton("122.256"),inet_aton("122.226."),inet_aton("");
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select inet_ntoa(NULL) AS `inet_ntoa(null)`,inet_aton(NULL) AS `inet_aton(null)`,inet_aton(_latin1'122.256') AS `inet_aton("122.256")`,inet_aton(_latin1'122.226.') AS `inet_aton("122.226.")`,inet_aton(_latin1'') AS `inet_aton("")`
create table t1 (x int);
insert into t1 values (null);
select * from t1 where x != 0;
x
drop table t1;
CREATE TABLE t1 (
indexed_field int default NULL,
KEY indexed_field (indexed_field)
);
INSERT INTO t1 VALUES (NULL),(NULL);
SELECT * FROM t1 WHERE indexed_field=NULL;
indexed_field
SELECT * FROM t1 WHERE indexed_field IS NULL;
indexed_field
NULL
NULL
SELECT * FROM t1 WHERE indexed_field<=>NULL;
indexed_field
NULL
NULL
DROP TABLE t1;
create table t1 (a int, b int) engine=myisam;
insert into t1 values(20,null);
select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
t2.b=t3.a;
b	ifnull(t2.b,"this is null")
NULL	this is null
select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
t2.b=t3.a order by 1;
b	ifnull(t2.b,"this is null")
NULL	this is null
insert into t1 values(10,null);
select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
t2.b=t3.a order by 1;
b	ifnull(t2.b,"this is null")
NULL	this is null
NULL	this is null
drop table t1;
CREATE TABLE t1 (a varchar(16) NOT NULL default '', b smallint(6) NOT NULL default 0, c datetime NOT NULL default '0000-00-00 00:00:00', d smallint(6) NOT NULL default 0);
INSERT INTO t1 SET a = "", d= "2003-01-14 03:54:55";
Warnings:
Warning	1265	Data truncated for column 'd' at row 1
UPDATE t1 SET d=1/NULL;
Warnings:
Warning	1265	Data truncated for column 'd' at row 1
UPDATE t1 SET d=NULL;
Warnings:
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'd' at row 1
INSERT INTO t1 (a) values (null);
ERROR 23000: Column 'a' cannot be null
INSERT INTO t1 (a) values (1/null);
ERROR 23000: Column 'a' cannot be null
INSERT INTO t1 (a) values (null),(null);
Warnings:
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'a' at row 1
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'a' at row 2
INSERT INTO t1 (b) values (null);
ERROR 23000: Column 'b' cannot be null
INSERT INTO t1 (b) values (1/null);
ERROR 23000: Column 'b' cannot be null
INSERT INTO t1 (b) values (null),(null);
Warnings:
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'b' at row 1
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'b' at row 2
INSERT INTO t1 (c) values (null);
ERROR 23000: Column 'c' cannot be null
INSERT INTO t1 (c) values (1/null);
ERROR 23000: Column 'c' cannot be null
INSERT INTO t1 (c) values (null),(null);
Warnings:
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'c' at row 1
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'c' at row 2
INSERT INTO t1 (d) values (null);
ERROR 23000: Column 'd' cannot be null
INSERT INTO t1 (d) values (1/null);
ERROR 23000: Column 'd' cannot be null
INSERT INTO t1 (d) values (null),(null);
Warnings:
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'd' at row 1
Warning	1263	Column set to default value; NULL supplied to NOT NULL column 'd' at row 2
select * from t1;
a	b	c	d
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
	0	0000-00-00 00:00:00	0
drop table t1;
create table t1 (a int not null, b int not null, index idx(a));
insert into t1 values
(1,1), (2,2), (3,3), (4,4), (5,5), (6,6),
(7,7), (8,8), (9,9), (10,10), (11,11), (12,12);
explain select * from t1 where a between 2 and 3;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using where
explain select * from t1 where a between 2 and 3 or b is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using where
drop table t1;
select cast(NULL as signed);
cast(NULL as signed)
NULL
create table t1(i int, key(i));
insert into t1 values(1);
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 select i*2 from t1;
insert into t1 values(null);
explain select * from t1 where i=2 or i is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref_or_null	i	i	5	const	9	Using where; Using index
select count(*) from t1 where i=2 or i is null;
count(*)
10
alter table t1 change i i int not null;
Warnings:
Warning	1265	Data truncated for column 'i' at row 513
explain select * from t1 where i=2 or i is null;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	i	i	4	const	7	Using index
select count(*) from t1 where i=2 or i is null;
count(*)
9
drop table t1;
set names latin2;
create table t1 select
null as c00,
if(1, null, 'string') as c01,
if(0, null, 'string') as c02,
ifnull(null, 'string') as c03,
ifnull('string', null) as c04,
case when 0 then null else 'string' end as c05,
case when 1 then null else 'string' end as c06,
coalesce(null, 'string') as c07,
coalesce('string', null) as c08,
least('string',null) as c09,
least(null, 'string') as c10,
greatest('string',null) as c11,
greatest(null, 'string') as c12,
nullif('string', null) as c13,
nullif(null, 'string') as c14,
trim('string' from null) as c15,
trim(null from 'string') as c16,
substring_index('string', null, 1) as c17,
substring_index(null, 'string', 1) as c18,
elt(1, null, 'string') as c19,
elt(1, 'string', null) as c20,
concat('string', null) as c21,
concat(null, 'string') as c22,
concat_ws('sep', 'string', null) as c23,
concat_ws('sep', null, 'string') as c24,
concat_ws(null, 'string', 'string') as c25,
make_set(3, 'string', null) as c26,
make_set(3, null, 'string') as c27,
export_set(3, null, 'off', 'sep') as c29,
export_set(3, 'on', null, 'sep') as c30,
export_set(3, 'on', 'off', null) as c31,
replace(null, 'from', 'to') as c32,
replace('str', null, 'to') as c33,
replace('str', 'from', null) as c34,
insert('str', 1, 2, null) as c35,
insert(null, 1, 2, 'str') as c36,
lpad('str', 10, null) as c37,
rpad(null, 10, 'str') as c38;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `c00` binary(0) default NULL,
  `c01` varchar(6) character set latin2 default NULL,
  `c02` varchar(6) character set latin2 default NULL,
  `c03` varchar(6) character set latin2 NOT NULL default '',
  `c04` varchar(6) character set latin2 default NULL,
  `c05` varchar(6) character set latin2 default NULL,
  `c06` varchar(6) character set latin2 default NULL,
  `c07` varchar(6) character set latin2 default NULL,
  `c08` varchar(6) character set latin2 default NULL,
  `c09` varchar(6) character set latin2 NOT NULL default '',
  `c10` varchar(6) character set latin2 NOT NULL default '',
  `c11` varchar(6) character set latin2 NOT NULL default '',
  `c12` varchar(6) character set latin2 NOT NULL default '',
  `c13` varchar(6) character set latin2 default NULL,
  `c14` char(0) character set latin2 default NULL,
  `c15` char(0) character set latin2 default NULL,
  `c16` varchar(6) character set latin2 default NULL,
  `c17` varchar(6) character set latin2 default NULL,
  `c18` char(0) character set latin2 default NULL,
  `c19` varchar(6) character set latin2 default NULL,
  `c20` varchar(6) character set latin2 default NULL,
  `c21` varchar(6) character set latin2 default NULL,
  `c22` varchar(6) character set latin2 default NULL,
  `c23` varchar(9) character set latin2 default NULL,
  `c24` varchar(9) character set latin2 default NULL,
  `c25` varchar(12) character set latin2 default NULL,
  `c26` varchar(7) character set latin2 default NULL,
  `c27` varchar(7) character set latin2 default NULL,
  `c29` varchar(381) character set latin2 default NULL,
  `c30` varchar(317) character set latin2 default NULL,
  `c31` varchar(192) character set latin2 default NULL,
  `c32` char(0) character set latin2 default NULL,
  `c33` varchar(3) character set latin2 default NULL,
  `c34` varchar(3) character set latin2 default NULL,
  `c35` varchar(3) character set latin2 default NULL,
  `c36` varchar(3) character set latin2 default NULL,
  `c37` varchar(10) character set latin2 default NULL,
  `c38` varchar(10) character set latin2 default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
select 
case 'str' when 'STR' then 'str' when null then 'null' end as c01,
case 'str' when null then 'null' when 'STR' then 'str' end as c02,
field(null, 'str1', 'str2') as c03,
field('str1','STR1', null) as c04,
field('str1', null, 'STR1') as c05,
'string' in ('STRING', null) as c08,
'string' in (null, 'STRING') as c09;
c01	c02	c03	c04	c05	c08	c09
str	str	0	1	2	1	1
set names latin1;
