CREATE TABLE t1(a int, b VARCHAR(5), PRIMARY KEY(a)); INSERT INTO t1 VALUES (1, 'a'), (2, 'ab'), (3, 'abc'), (4, 'abcd'), (5, 'abcde'); ALTER TABLE t1 ADD KEY k2 (b(4)); ANALYZE TABLE t1; --source include/func_prefix_key.inc DROP TABLE t1; CREATE TABLE t1(a int, b VARCHAR(5), PRIMARY KEY(a)) DEFAULT CHARSET=latin1, COLLATE latin1_bin; INSERT INTO t1 VALUES (1, 'a'), (2, 'ab'), (3, 'abc'), (4, 'abcd'), (5, 'abcde'); ALTER TABLE t1 ADD KEY k2 (b(4)); ANALYZE TABLE t1; --source include/func_prefix_key.inc DROP TABLE t1; # Currently XEngine doesn't support utf32 collation CREATE TABLE t1(a int, b VARCHAR(5), PRIMARY KEY(a)) DEFAULT CHARSET=utf8; INSERT INTO t1 VALUES (1, 'a'), (2, 'ab'), (3, 'abc'), (4, 'abcd'), (5, 'abcde'); ALTER TABLE t1 ADD KEY k2 (b(4)); ANALYZE TABLE t1; --source include/func_prefix_key.inc DROP TABLE t1; # Test for TEXT field. CREATE TABLE t1(a int, b TEXT, PRIMARY KEY(a)); INSERT INTO t1 VALUES (1, 'a'), (2, 'ab'), (3, 'abc'), (4, 'abcd'), (5, 'abcde'); ALTER TABLE t1 ADD KEY k2 (b(4)); ANALYZE TABLE t1; --source include/func_prefix_key.inc DROP TABLE t1; # More tests with the indexes with different prefix length. CREATE TABLE t1(a int, b VARCHAR(5), PRIMARY KEY(a)) DEFAULT CHARSET=utf8; INSERT INTO t1 VALUES (1, 'a'), (2, 'ab'), (3, 'abc'), (4, 'abcd'), (5, 'abcde'), (6, 'abcdf'); ALTER TABLE t1 ADD KEY k2 (b(4)); ALTER TABLE t1 ADD KEY k3 (b(2)); ALTER TABLE t1 ADD KEY k4 (a, b(3)); ANALYZE TABLE t1; --echo # k2 index used since it's covering. EXPLAIN SELECT COUNT(*) FROM t1 WHERE b like 'abc%'; SELECT COUNT(*) FROM t1 WHERE b like 'abc%'; --echo # k4 index used since it's covering. EXPLAIN SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abc%'; SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abc%'; --echo # k3 index is used since it's shorters key. EXPLAIN SELECT COUNT(*) FROM t1 WHERE b like 'ab%'; SELECT COUNT(*) FROM t1 WHERE b like 'ab%'; --echo # Index access is not used, no covering keys. EXPLAIN SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abcde%'; SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abcde%'; --echo # k2 index used since it's covering. EXPLAIN SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abcd%'; SELECT COUNT(*) FROM t1 WHERE a > 4 AND b like 'abcd%'; --echo # Index access is not used, no covering keys. EXPLAIN SELECT b like 'abcdf%' FROM t1 WHERE a > 4 AND b like 'abcd%'; SELECT b like 'abcdf%' FROM t1 WHERE a > 4 AND b like 'abcd%'; --echo # Index access is used since k4 is covering. EXPLAIN SELECT b like 'ab%' FROM t1 WHERE a > 4 AND b like 'a%'; SELECT b like 'ab%' FROM t1 WHERE a > 4 AND b like 'a%'; --echo # Index access is used since k3 is forced and covering. EXPLAIN SELECT b like 'ab%' FROM t1 FORCE INDEX(k3) WHERE a > 4 AND b like 'a%'; SELECT b like 'ab%' FROM t1 FORCE INDEX(k3) WHERE a > 4 AND b like 'a%'; --echo # No index access is used since second argument is not const. EXPLAIN SELECT COUNT(*) FROM t1 WHERE b like a; SELECT COUNT(*) FROM t1 WHERE b like a; DROP TABLE t1; CREATE TABLE t1(a int, b TEXT, c TEXT, PRIMARY KEY(a)); INSERT INTO t1 VALUES (1, 'a', 'a'), (2, 'ab', 'ab'), (3, 'abc', 'abc'), (4, 'abcd', 'abcd'), (5, 'abcde', 'abcde'); ALTER TABLE t1 ADD KEY k2 (b(4), c(3)); ANALYZE TABLE t1; --echo # Index access is used since key is covering. EXPLAIN SELECT COUNT(*) FROM t1 WHERE b like 'aaaa'; DROP TABLE t1; --echo # --echo # Bug#27660560 RECENT REGRESSION: CRASH IN CHECK_COVERING_PREFIX_KEYS. --echo # CREATE TABLE t1(f1 BLOB, KEY(f1(1))) ; INSERT INTO t1 VALUES ('ccc'), ('aa'); ANALYZE TABLE t1; SELECT (f1 LIKE null) from t1; --error ER_INVALID_JSON_TEXT_IN_PARAM SELECT 1 FROM t1 WHERE f1 NOT LIKE json_merge('' ,'+' ); --error ER_INVALID_JSON_TEXT_IN_PARAM SELECT 1 FROM t1 WHERE f1 LIKE json_contains('key2' ,'key4' ); SELECT 1 FROM t1 WHERE f1 LIKE json_depth(null); # Tests below should use index access. EXPLAIN SELECT (f1 LIKE null) from t1; EXPLAIN SELECT (f1 LIKE null) from t1 WHERE f1 LIKE 'a%'; DROP TABLE t1; --source suite/xengine/include/check_xengine_log_error.inc