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987e146604
Constant expressions in WHERE/HAVING/ON clauses aren't cached and evaluated
for each row. This causes slowdown of query execution especially if constant
UDF/SP function are used.
Now WHERE/HAVING/ON expressions are analyzed in the top-bottom direction with
help of the compile function. When analyzer meets a constant item it
sets a flag for the tree transformer to cache the item and doesn't allow tree
walker to go deeper. Thus, the topmost item of a constant expression if
cached. This is done after all other optimizations were applied to
WHERE/HAVING/ON expressions
A helper function called cache_const_exprs is added to the JOIN class.
It calls compile method with caching analyzer and transformer on WHERE,
HAVING, ON expressions if they're present.
The cache_const_expr_analyzer and cache_const_expr_transformer functions are
added to the Item class. The first one check if the item can be cached and
the second caches it if so.
A new Item_cache_datetime class is derived from the Item_cache class.
It caches both int and string values of the underlying item independently to
avoid DATETIME aware int-to-string conversion. Thus it completely relies on
the ability of the underlying item to correctly convert DATETIME value from
int to string and vice versa.
mysql-test/r/func_like.result:
A test case result is corrected after fixing bug#33546.
mysql-test/r/func_time.result:
A test case result is corrected after fixing bug#33546.
mysql-test/r/select.result:
Added a test case for the bug#33546.
mysql-test/r/subselect.result:
A test case result is corrected after fixing bug#33546.
mysql-test/r/udf.result:
Added a test case for the bug#33546.
mysql-test/t/select.test:
Added a test case for the bug#33546.
mysql-test/t/udf.test:
Added a test case for the bug#33546.
sql/item.cc:
Bug#33546: Slowdown on re-evaluation of constant expressions.
The cache_const_expr_analyzer and cache_const_expr_transformer functions are
added to the Item class. The first one check if the item can be cached and
the second caches it if so.
Item_cache_datetime class implementation is added.
sql/item.h:
Bug#33546: Slowdown on re-evaluation of constant expressions.
Item_ref and Item_cache classes now returns basic_const_item
from underlying item.
The cache_const_expr_analyzer and cache_const_expr_transformer functions are
added to the Item class.
sql/sql_select.cc:
Bug#33546: Slowdown on re-evaluation of constant expressions.
A helper function called cache_const_exprs is added to the JOIN class.
It calls compile method with caching analyzer and transformer on WHERE,
HAVING, ON expressions if they're present.
sql/sql_select.h:
Bug#33546: Slowdown on re-evaluation of constant expressions.
A helper function called cache_const_exprs is added to the JOIN class.
171 lines
3.9 KiB
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171 lines
3.9 KiB
Text
drop table if exists t1;
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create table t1 (a varchar(10), key(a));
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insert into t1 values ("a"),("abc"),("abcd"),("hello"),("test");
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explain extended select * from t1 where a like 'abc%';
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 index a a 13 NULL 5 20.00 Using where; Using index
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Warnings:
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Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` like 'abc%')
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explain extended select * from t1 where a like concat('abc','%');
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 index a a 13 NULL 5 20.00 Using where; Using index
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Warnings:
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Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` like <cache>(concat('abc','%')))
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select * from t1 where a like "abc%";
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a
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abc
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abcd
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select * from t1 where a like concat("abc","%");
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a
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abc
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abcd
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select * from t1 where a like "ABC%";
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a
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abc
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abcd
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select * from t1 where a like "test%";
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a
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test
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select * from t1 where a like "te_t";
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a
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test
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select * from t1 where a like "%a%";
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a
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a
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abc
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abcd
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select * from t1 where a like "%abcd%";
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a
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abcd
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select * from t1 where a like "%abc\d%";
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a
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abcd
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drop table t1;
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create table t1 (a varchar(10), key(a));
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insert into t1 values ('a'), ('a\\b');
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select * from t1 where a like 'a\\%' escape '#';
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a
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a\b
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select * from t1 where a like 'a\\%' escape '#' and a like 'a\\\\b';
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a
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a\b
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prepare stmt1 from 'select * from t1 where a like \'a\\%\' escape ?';
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set @esc='#';
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execute stmt1 using @esc;
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a
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a\b
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deallocate prepare stmt1;
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drop table t1;
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create table t1 (a datetime);
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insert into t1 values ('2004-03-11 12:00:21');
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select * from t1 where a like '2004-03-11 12:00:21';
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a
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2004-03-11 12:00:21
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drop table t1;
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SET NAMES koi8r;
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CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET koi8r);
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INSERT INTO t1 VALUES ('ÆÙ×Á'),('æÙ×Á'),('Æù×Á'),('ÆÙ÷Á'),('ÆÙ×á'),('æù÷á');
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INSERT INTO t1 VALUES ('ÆÙ×ÁÐÒÏÌÄÖ'),('æÙ×ÁÐÒÏÌÄÖ'),('Æù×ÁÐÒÏÌÄÖ'),('ÆÙ÷ÁÐÒÏÌÄÖ');
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INSERT INTO t1 VALUES ('ÆÙ×áÐÒÏÌÄÖ'),('ÆÙ×ÁðÒÏÌÄÖ'),('ÆÙ×ÁÐòÏÌÄÖ'),('ÆÙ×ÁÐÒïÌÄÖ');
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INSERT INTO t1 VALUES ('ÆÙ×ÁÐÒÏìÄÖ'),('ÆÙ×ÁÐÒÏÌäÖ'),('ÆÙ×ÁÐÒÏÌÄö'),('æù÷áðòïìäö');
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SELECT * FROM t1 WHERE a LIKE '%Æù×Á%';
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a
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ÆÙ×Á
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æÙ×Á
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Æù×Á
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ÆÙ÷Á
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ÆÙ×á
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æù÷á
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ÆÙ×ÁÐÒÏÌÄÖ
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æÙ×ÁÐÒÏÌÄÖ
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Æù×ÁÐÒÏÌÄÖ
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ÆÙ÷ÁÐÒÏÌÄÖ
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ÆÙ×áÐÒÏÌÄÖ
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ÆÙ×ÁðÒÏÌÄÖ
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ÆÙ×ÁÐòÏÌÄÖ
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ÆÙ×ÁÐÒïÌÄÖ
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ÆÙ×ÁÐÒÏìÄÖ
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ÆÙ×ÁÐÒÏÌäÖ
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ÆÙ×ÁÐÒÏÌÄö
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æù÷áðòïìäö
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SELECT * FROM t1 WHERE a LIKE '%Æù×%';
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a
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ÆÙ×Á
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æÙ×Á
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Æù×Á
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ÆÙ÷Á
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ÆÙ×á
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æù÷á
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ÆÙ×ÁÐÒÏÌÄÖ
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æÙ×ÁÐÒÏÌÄÖ
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Æù×ÁÐÒÏÌÄÖ
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ÆÙ÷ÁÐÒÏÌÄÖ
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ÆÙ×áÐÒÏÌÄÖ
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ÆÙ×ÁðÒÏÌÄÖ
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ÆÙ×ÁÐòÏÌÄÖ
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ÆÙ×ÁÐÒïÌÄÖ
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ÆÙ×ÁÐÒÏìÄÖ
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ÆÙ×ÁÐÒÏÌäÖ
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ÆÙ×ÁÐÒÏÌÄö
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æù÷áðòïìäö
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SELECT * FROM t1 WHERE a LIKE 'Æù×Á%';
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a
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ÆÙ×Á
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æÙ×Á
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Æù×Á
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ÆÙ÷Á
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ÆÙ×á
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æù÷á
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ÆÙ×ÁÐÒÏÌÄÖ
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æÙ×ÁÐÒÏÌÄÖ
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Æù×ÁÐÒÏÌÄÖ
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ÆÙ÷ÁÐÒÏÌÄÖ
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ÆÙ×áÐÒÏÌÄÖ
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ÆÙ×ÁðÒÏÌÄÖ
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ÆÙ×ÁÐòÏÌÄÖ
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ÆÙ×ÁÐÒïÌÄÖ
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ÆÙ×ÁÐÒÏìÄÖ
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ÆÙ×ÁÐÒÏÌäÖ
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ÆÙ×ÁÐÒÏÌÄö
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æù÷áðòïìäö
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DROP TABLE t1;
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SET NAMES cp1250;
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CREATE TABLE t1 (a varchar(250) NOT NULL) DEFAULT CHARACTER SET=cp1250;
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INSERT INTO t1 VALUES
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('Techni Tapes Sp. z o.o.'),
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('Pojazdy Szynowe PESA Bydgoszcz SA Holding'),
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('AKAPESTER 1 P.P.H.U.'),
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('Pojazdy Szynowe PESA Bydgoszcz S A Holding'),
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('PPUH PESKA-I Maria Struniarska');
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select * from t1 where a like '%PESA%';
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a
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Pojazdy Szynowe PESA Bydgoszcz SA Holding
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Pojazdy Szynowe PESA Bydgoszcz S A Holding
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select * from t1 where a like '%PESA %';
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a
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Pojazdy Szynowe PESA Bydgoszcz SA Holding
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Pojazdy Szynowe PESA Bydgoszcz S A Holding
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select * from t1 where a like '%PES%';
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a
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Techni Tapes Sp. z o.o.
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Pojazdy Szynowe PESA Bydgoszcz SA Holding
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AKAPESTER 1 P.P.H.U.
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Pojazdy Szynowe PESA Bydgoszcz S A Holding
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PPUH PESKA-I Maria Struniarska
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select * from t1 where a like '%PESKA%';
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a
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PPUH PESKA-I Maria Struniarska
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select * from t1 where a like '%ESKA%';
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a
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PPUH PESKA-I Maria Struniarska
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DROP TABLE t1;
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select _cp866'aaaaaaaaa' like _cp866'%aaaa%' collate cp866_bin;
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_cp866'aaaaaaaaa' like _cp866'%aaaa%' collate cp866_bin
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1
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set names koi8r;
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select 'andre%' like 'andreÊ%' escape 'Ê';
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'andre%' like 'andreÊ%' escape 'Ê'
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1
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select _cp1251'andre%' like convert('andreÊ%' using cp1251) escape 'Ê';
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_cp1251'andre%' like convert('andreÊ%' using cp1251) escape 'Ê'
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1
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