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	c51d7acfcc
	
	
	
		
			
			the result takes its charset/collation attributes from the character string, e.g. SELECT func(NULL, _latin2'string') now returns a latin2 result. This is done by introducing a new derivation (aka coercibility) level DERIVATION_IGNORABLE, which is used with Item_null. 2. 'Pure' NULL is now BINARY(0), not CHAR(0). I.e. NULL is now more typeless.
		
			
				
	
	
		
			189 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			189 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| # Initialise
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| --disable_warnings
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| drop table if exists t1;
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| --enable_warnings
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| 
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| #
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| # Testing of NULL in a lot of different places
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| #
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| 
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| 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;
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| 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;
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| select 1 | NULL,1 & NULL,1+NULL,1-NULL;
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| select NULL=NULL,NULL<>NULL,IFNULL(NULL,1.1)+0,IFNULL(NULL,1) | 0;
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| select strcmp("a",NULL),(1<NULL)+0.0,NULL regexp "a",null like "a%","a%" like null;
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| select concat("a",NULL),replace(NULL,"a","b"),replace("string","i",NULL),replace("string",NULL,"i"),insert("abc",1,1,NULL),left(NULL,1);
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| select repeat("a",0),repeat("ab",5+5),repeat("ab",-1),reverse(NULL);
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| select field(NULL,"a","b","c");
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| 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;
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| 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;
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| SELECT NULL AND NULL, 1 AND NULL, NULL AND 1, NULL OR NULL, 0 OR NULL, NULL OR 0;
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| SELECT (NULL OR NULL) IS NULL;
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| select NULL AND 0, 0 and NULL;
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| select inet_ntoa(null),inet_aton(null),inet_aton("122.256"),inet_aton("122.226."),inet_aton("");
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| explain extended select inet_ntoa(null),inet_aton(null),inet_aton("122.256"),inet_aton("122.226."),inet_aton("");
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| 
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| create table t1 (x int);
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| insert into t1 values (null);
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| select * from t1 where x != 0;
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| drop table t1;
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| 
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| #
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| # Test problem med index on NULL columns and testing with =NULL;
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| #
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| 
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| CREATE TABLE t1 (
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|   indexed_field int default NULL,
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|   KEY indexed_field (indexed_field)
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| );
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| INSERT INTO t1 VALUES (NULL),(NULL);
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| SELECT * FROM t1 WHERE indexed_field=NULL;
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| SELECT * FROM t1 WHERE indexed_field IS NULL;
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| SELECT * FROM t1 WHERE indexed_field<=>NULL;
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| DROP TABLE t1;
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| 
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| #
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| # Testing of IFNULL
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| #
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| create table t1 (a int, b int) engine=myisam;
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| insert into t1 values(20,null);
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| select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
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| t2.b=t3.a;
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| select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
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| t2.b=t3.a order by 1;
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| insert into t1 values(10,null);
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| select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on
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| t2.b=t3.a order by 1;
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| drop table t1;
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| 
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| #
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| # Test inserting and updating with NULL
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| #
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| CREATE TABLE t1 (a varchar(16) NOT NULL, b smallint(6) NOT NULL, c datetime NOT NULL, d smallint(6) NOT NULL);
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| INSERT INTO t1 SET a = "", d= "2003-01-14 03:54:55";
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| UPDATE t1 SET d=1/NULL;
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| UPDATE t1 SET d=NULL;
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| --error 1048
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| INSERT INTO t1 (a) values (null);
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| --error 1048
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| INSERT INTO t1 (a) values (1/null);
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| INSERT INTO t1 (a) values (null),(null);
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| --error 1048
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| INSERT INTO t1 (b) values (null);
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| --error 1048
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| INSERT INTO t1 (b) values (1/null);
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| INSERT INTO t1 (b) values (null),(null);
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| --error 1048
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| INSERT INTO t1 (c) values (null);
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| --error 1048
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| INSERT INTO t1 (c) values (1/null);
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| INSERT INTO t1 (c) values (null),(null);
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| --error 1048
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| INSERT INTO t1 (d) values (null);
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| --error 1048
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| INSERT INTO t1 (d) values (1/null);
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| INSERT INTO t1 (d) values (null),(null);
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| select * from t1;
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| drop table t1;
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| 
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| #
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| # Test to check elimination of IS NULL predicate for a non-nullable attribute
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| # (bug #1990)  
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| #
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| create table t1 (a int not null, b int not null, index idx(a));
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| insert into t1 values
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|   (1,1), (2,2), (3,3), (4,4), (5,5), (6,6),
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|   (7,7), (8,8), (9,9), (10,10), (11,11), (12,12);
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| explain select * from t1 where a between 2 and 3;
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| explain select * from t1 where a between 2 and 3 or b is null;
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| drop table t1;
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| select cast(NULL as signed);
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| 
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| #
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| # Test case for bug #4256
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| #
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| 
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| create table t1(i int, key(i));
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| insert into t1 values(1);
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| insert into t1 select i*2 from t1;
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| explain select * from t1 where i=2 or i is null;
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| alter table t1 change i i int not null;
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| explain select * from t1 where i=2 or i is null;
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| drop table t1;
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| 
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| #
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| # NULL has its own type BINARY(0) by default.
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| # But NULL should be weaker than a constant
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| # when mixing charsets/collations
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| #
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| set names latin2;
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| # Check that result type is taken from a non-null string
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| create table t1 select
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|   null as c00,
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|   if(1, null, 'string') as c01,
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|   if(0, null, 'string') as c02,
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|   ifnull(null, 'string') as c03,
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|   ifnull('string', null) as c04,
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|   case when 0 then null else 'string' end as c05,
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|   case when 1 then null else 'string' end as c06,
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|   coalesce(null, 'string') as c07,
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|   coalesce('string', null) as c08,
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|   least('string',null) as c09,
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|   least(null, 'string') as c10,
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|   greatest('string',null) as c11,
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|   greatest(null, 'string') as c12,
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|   nullif('string', null) as c13,
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|   nullif(null, 'string') as c14,
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|   trim('string' from null) as c15,
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|   trim(null from 'string') as c16,
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|   substring_index('string', null, 1) as c17,
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|   substring_index(null, 'string', 1) as c18,
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|   elt(1, null, 'string') as c19,
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|   elt(1, 'string', null) as c20,
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|   concat('string', null) as c21,
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|   concat(null, 'string') as c22,
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|   concat_ws('sep', 'string', null) as c23,
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|   concat_ws('sep', null, 'string') as c24,
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|   concat_ws(null, 'string', 'string') as c25,
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|   make_set(3, 'string', null) as c26,
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|   make_set(3, null, 'string') as c27,
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|   export_set(3, null, 'off', 'sep') as c29,
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|   export_set(3, 'on', null, 'sep') as c30,
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|   export_set(3, 'on', 'off', null) as c31,
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|   replace(null, 'from', 'to') as c32,
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|   replace('str', null, 'to') as c33,
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|   replace('str', 'from', null) as c34,
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|   insert('str', 1, 2, null) as c35,
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|   insert(null, 1, 2, 'str') as c36,
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|   lpad('str', 10, null) as c37,
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|   rpad(null, 10, 'str') as c38;
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|   
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| show create table t1;
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| drop table t1;
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| 
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| #
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| # Check that comparison is done according to
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| # non-null string collation, i.e. case insensitively,
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| # rather than according to NULL's collation, i.e. case sensitively
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| #
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| -- in field
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| select 
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|   case 'str' when 'STR' then 'str' when null then 'null' end as c01,
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|   case 'str' when null then 'null' when 'STR' then 'str' end as c02,
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|   field(null, 'str1', 'str2') as c03,
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|   field('str1','STR1', null) as c04,
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|   field('str1', null, 'STR1') as c05,
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|   'string' in ('STRING', null) as c08,
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|   'string' in (null, 'STRING') as c09;
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| 
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| # Restore charset to the default value.
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| set names latin1;
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