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CREATE TABLE t1 (id int(11) NOT NULL PRIMARY KEY, name varchar(20),
INDEX (name)) ENGINE=InnoDB;
CREATE TABLE t2 (id int(11) NOT NULL PRIMARY KEY, fkey int(11),
FOREIGN KEY (fkey) REFERENCES t2(id)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,'A1'),(2,'A2'),(3,'B');
INSERT INTO t2 VALUES (1,1),(2,2),(3,2),(4,3),(5,3);
EXPLAIN
SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
WHERE t1.name LIKE 'A%';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index PRIMARY,name name 23 NULL 3 Using where; Using index
1 SIMPLE t2 ref fkey fkey 5 test.t1.id 1 Using where; Using index
EXPLAIN
SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
WHERE t1.name LIKE 'A%' OR FALSE;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 index NULL fkey 5 NULL 5 Using index
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.fkey 1 Using where
DROP TABLE t1,t2;
#
# BUG#58456: Assertion 0 in QUICK_INDEX_MERGE_SELECT::need_sorted_output
# in opt_range.h
#
CREATE TABLE t1 (
col_int INT,
col_int_key INT,
pk INT NOT NULL,
PRIMARY KEY (pk),
KEY col_int_key (col_int_key)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (NULL,1,1), (6,2,2), (5,3,3), (NULL,4,4);
INSERT INTO t1 VALUES (1,NULL,6), (8,5,7), (NULL,8,8), (8,NULL,5);
CREATE TABLE t2 (
pk INT PRIMARY KEY
) ENGINE=InnoDB;
EXPLAIN SELECT t1.pk
FROM t2 LEFT JOIN t1 ON t2.pk = t1.col_int
WHERE t1.col_int_key BETWEEN 5 AND 6
AND t1.pk IS NULL OR t1.pk IN (5)
ORDER BY pk;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY,col_int_key PRIMARY 4 const 2 Using where
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.col_int 1 Using index
SELECT t1.pk
FROM t2 LEFT JOIN t1 ON t2.pk = t1.col_int
WHERE t1.col_int_key BETWEEN 5 AND 6
AND t1.pk IS NULL OR t1.pk IN (5)
ORDER BY pk;
pk
DROP TABLE t1,t2;
# End BUG#58456
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