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CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, KEY(a)) ENGINE=LevelDB;
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INSERT INTO t1 VALUES (1, NULL),(2, 8);
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SELECT ( 3 ) NOT IN ( SELECT a FROM t1 );
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( 3 ) NOT IN ( SELECT a FROM t1 )
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1
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EXPLAIN EXTENDED
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SELECT ( 3 ) IN ( SELECT a FROM t1 );
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL No tables used
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2 DEPENDENT SUBQUERY t1 index_subquery a a 5 const 20 100.00 Using index
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Warnings:
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Note 1003 /* select#1 */ select <in_optimizer>(3,<exists>(<index_lookup>(<cache>(3) in t1 on a checking NULL having <is_not_null_test>(`test`.`t1`.`a`)))) AS `( 3 ) IN ( SELECT a FROM t1 )`
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Same query without the key on `a` returns NULL. Same query with the key and InnoDB table also returns NULL.
Test case:
CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, KEY(a)) ENGINE=LevelDB;
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INSERT INTO t1 VALUES (1, NULL),(2, 8);
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SELECT ( 3 ) NOT IN ( SELECT a FROM t1 );
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Version info:
revision-id: psergey@askmonty.org-20130125181032-kuuhprzmkes6p9u0
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revno: 4517
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branch-nick: mysql-5.6-leveldb
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