# # Table elimination (MWL#17) tests # --source include/have_sequence.inc --disable_warnings drop table if exists t0, t1, t2, t3, t4, t5, t6; drop view if exists v1, v2; --enable_warnings SET @save_optimizer_switch=@@optimizer_switch; SET optimizer_switch='outer_join_with_cache=off'; create table t1 (a int); insert into t1 values (0),(1),(2),(3); create table t0 as select * from t1; create table t2 (a int primary key, b int) as select a, a as b from t1 where a in (1,2); create table t3 (a int primary key, b int) as select a, a as b from t1 where a in (1,3); --echo # This will be eliminated: explain select t1.a from t1 left join t2 on t2.a=t1.a; explain extended select t1.a from t1 left join t2 on t2.a=t1.a; select t1.a from t1 left join t2 on t2.a=t1.a; --echo # This will not be eliminated as t2.b is in in select list: explain select * from t1 left join t2 on t2.a=t1.a; --echo # This will not be eliminated as t2.b is in in order list: explain select t1.a from t1 left join t2 on t2.a=t1.a order by t2.b; --echo # This will not be eliminated as t2.b is in group list: explain select t1.a from t1 left join t2 on t2.a=t1.a group by t2.b; --echo # This will not be eliminated as t2.b is in the WHERE explain select t1.a from t1 left join t2 on t2.a=t1.a where t2.b < 3 or t2.b is null; --echo # Elimination of multiple tables: explain select t1.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a; --echo # Elimination of multiple tables (2): explain select t1.a from t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a; --echo # Elimination when done within an outer join nest: explain extended select t0.* from t0 left join (t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a) on t0.a=t1.a; --echo # Elimination with aggregate functions explain select count(*) from t1 left join t2 on t2.a=t1.a; explain select count(1) from t1 left join t2 on t2.a=t1.a; explain select count(1) from t1 left join t2 on t2.a=t1.a group by t1.a; --echo This must not use elimination: explain select count(1) from t1 left join t2 on t2.a=t1.a group by t2.a; drop table t0, t1, t2, t3; # This will stand for elim_facts create table t0 ( id integer, primary key (id)); # Attribute1, non-versioned create table t1 ( id integer, attr1 integer, primary key (id), key (attr1) ); # Attribute2, time-versioned create table t2 ( id integer, attr2 integer, fromdate date, primary key (id, fromdate), key (attr2,fromdate) ); insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); insert into t0 select A.id + 10*B.id from t0 A, t0 B where B.id > 0; insert into t1 select id, id from t0; insert into t2 select id, id, date_add('2009-06-22', interval id day) from t0; insert into t2 select id, id+1, date_add('2008-06-22', interval id day) from t0; create view v1 as select f.id, a1.attr1, a2.attr2 from t0 f left join t1 a1 on a1.id=f.id left join t2 a2 on a2.id=f.id and a2.fromdate=(select MAX(fromdate) from t2 where id=a2.id); create view v2 as select f.id, a1.attr1, a2.attr2 from t0 f left join t1 a1 on a1.id=f.id left join t2 a2 on a2.id=f.id and a2.fromdate=(select MAX(fromdate) from t2 where id=f.id); --echo This should use one table: explain select id from v1 where id=2; --echo This should use one table: explain extended select id from v1 where id in (1,2,3,4); --echo This should use facts and a1 tables: explain extended select id from v1 where attr1 between 12 and 14; --echo This should use facts, a2 and its subquery: explain extended select id from v1 where attr2 between 12 and 14; # Repeat for v2: --echo This should use one table: explain select id from v2 where id=2; --echo This should use one table: explain extended select id from v2 where id in (1,2,3,4); --echo This should use facts and a1 tables: explain extended select id from v2 where attr1 between 12 and 14; --echo This should use facts, a2 and its subquery: explain extended select id from v2 where attr2 between 12 and 14; drop view v1, v2; drop table t0, t1, t2; # # Tests for the code that uses t.keypartX=func(t.keypartY) equalities to # make table elimination inferences # create table t1 (a int); insert into t1 values (0),(1),(2),(3); create table t2 (pk1 int, pk2 int, pk3 int, col int, primary key(pk1, pk2, pk3)); insert into t2 select a,a,a,a from t1; --echo This must use only t1: explain select t1.* from t1 left join t2 on t2.pk1=t1.a and t2.pk2=t2.pk1+1 and t2.pk3=t2.pk2+1; --echo This must use only t1: explain select t1.* from t1 left join t2 on t2.pk1=t1.a and t2.pk3=t2.pk1+1 and t2.pk2=t2.pk3+1; --echo This must use both: explain select t1.* from t1 left join t2 on t2.pk1=t1.a and t2.pk3=t2.pk1+1 and t2.pk2=t2.pk3+t2.col; --echo This must use only t1: explain select t1.* from t1 left join t2 on t2.pk2=t1.a and t2.pk1=t2.pk2+1 and t2.pk3=t2.pk1; drop table t1, t2; # # Check that equality propagation is taken into account # create table t1 (pk int primary key, col int); insert into t1 values (1,1),(2,2); create table t2 like t1; insert into t2 select * from t1; create table t3 like t1; insert into t3 select * from t1; explain select t1.* from t1 left join ( t2 left join t3 on t3.pk=t2.col) on t2.col=t1.col; explain select t1.*, t2.* from t1 left join (t2 left join t3 on t3.pk=t2.col) on t2.pk=t1.col; explain select t1.* from t1 left join ( t2 left join t3 on t3.pk=t2.col or t3.pk=t2.col) on t2.col=t1.col or t2.col=t1.col; explain select t1.*, t2.* from t1 left join (t2 left join t3 on t3.pk=t2.col or t3.pk=t2.col) on t2.pk=t1.col or t2.pk=t1.col; drop table t1, t2, t3; --echo # --echo # Check things that look like functional dependencies but really are not --echo # create table t1 (a char(10) character set latin1 collate latin1_general_ci primary key); insert into t1 values ('foo'); insert into t1 values ('bar'); create table t2 (a char(10) character set latin1 collate latin1_general_cs primary key); insert into t2 values ('foo'); insert into t2 values ('FOO'); -- echo this must not use table elimination: explain select t1.* from t1 left join t2 on t2.a='foo' collate latin1_general_ci; -- echo this must not use table elimination: explain select t1.* from t1 left join t2 on t2.a=t1.a collate latin1_general_ci; drop table t1,t2; create table t1 (a int primary key); insert into t1 values (1),(2); create table t2 (a char(10) primary key); insert into t2 values ('1'),('1.0'); -- echo this must not use table elimination: explain select t1.* from t1 left join t2 on t2.a=1; -- echo this must not use table elimination: explain select t1.* from t1 left join t2 on t2.a=t1.a; drop table t1, t2; # partial unique keys do not work at the moment, although they are able to # provide one-match guarantees: create table t1 (a char(10) primary key); insert into t1 values ('foo'),('bar'); create table t2 (a char(10), unique key(a(2))); insert into t2 values ('foo'),('bar'),('boo'),('car'),('coo'),('par'),('doo'),('tar'); explain select t1.* from t1 left join t2 on t2.a=t1.a; drop table t1, t2; --echo # --echo # check UPDATE/DELETE that look like they could be eliminated --echo # create table t1 (a int primary key, b int); insert into t1 values (1,1),(2,2),(3,3); create table t2 like t1; insert into t2 select * from t1; update t1 left join t2 using (a) set t2.a=t2.a+100; select * from t1; select * from t2; delete from t2; insert into t2 select * from t1; delete t2 from t1 left join t2 using (a); select * from t1; select * from t2; drop table t1, t2; --echo # --echo # Tests with various edge-case ON expressions --echo # create table t1 (a int, b int, c int, d int); insert into t1 values (0,0,0,0),(1,1,1,1),(2,2,2,2),(3,3,3,3); create table t2 (pk int primary key, b int) as select a as pk, a as b from t1 where a in (1,2); create table t3 (pk1 int, pk2 int, b int, unique(pk1,pk2)); insert into t3 select a as pk1, a as pk2, a as b from t1 where a in (1,3); explain select t1.a from t1 left join t2 on t2.pk=t1.a and t2.b<t1.b; explain select t1.a from t1 left join t2 on t2.pk=t1.a or t2.b<t1.b; explain select t1.a from t1 left join t2 on t2.b<t1.b or t2.pk=t1.a; explain select t1.a from t1 left join t2 on t2.pk between 10 and 20; explain select t1.a from t1 left join t2 on t2.pk between 0.5 and 1.5; explain select t1.a from t1 left join t2 on t2.pk between 10 and 10; explain select t1.a from t1 left join t2 on t2.pk in (10); explain select t1.a from t1 left join t2 on t2.pk in (t1.a); explain select t1.a from t1 left join t2 on TRUE; explain select t1.a from t1 left join t3 on t3.pk1=t1.a and t3.pk2 IS NULL; drop table t1,t2,t3; --echo # --echo # Multi-equality tests --echo # create table t1 (a int, b int, c int, d int); insert into t1 values (0,0,0,0),(1,1,1,1),(2,2,2,2),(3,3,3,3); create table t2 (pk int primary key, b int, c int); insert into t2 select a,a,a from t1 where a in (1,2); explain select t1.* from t1 left join t2 on t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b where t1.d=1; explain select t1.* from t1 left join t2 on (t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b) or (t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b) where t1.d=1; --echo #This can't be eliminated: explain select t1.* from t1 left join t2 on (t2.pk=t2.c and t2.b=t1.a and t2.c=t1.b) or (t2.pk=t2.c and t1.a=t1.b and t2.c=t1.b) where t1.d=1; explain select t1.* from t1 left join t2 on (t2.pk=t2.c and t2.b=t1.a and t2.c=t1.b) or (t2.pk=t2.c and t2.c=t1.b) ; explain select t1.* from t1 left join t2 on t2.pk=3 or t2.pk= 4; explain select t1.* from t1 left join t2 on t2.pk=3 or t2.pk= 3; explain select t1.* from t1 left join t2 on (t2.pk=3 and t2.b=3) or (t2.pk= 4 and t2.b=3); drop table t1, t2; --echo # --echo # LPBUG#523593: Running RQG optimizer_no_subquery crashes MariaDB --echo # CREATE TABLE t1 ( `pk` int(11) NOT NULL AUTO_INCREMENT, `col_int_nokey` int(11) DEFAULT NULL, `col_int_key` int(11) DEFAULT NULL, `col_date_key` date DEFAULT NULL, `col_date_nokey` date DEFAULT NULL, `col_time_key` time DEFAULT NULL, `col_time_nokey` time DEFAULT NULL, `col_datetime_key` datetime DEFAULT NULL, `col_datetime_nokey` datetime DEFAULT NULL, `col_varchar_key` varchar(1) DEFAULT NULL, `col_varchar_nokey` varchar(1) DEFAULT NULL, PRIMARY KEY (`pk`), KEY `col_int_key` (`col_int_key`), KEY `col_date_key` (`col_date_key`), KEY `col_time_key` (`col_time_key`), KEY `col_datetime_key` (`col_datetime_key`), KEY `col_varchar_key` (`col_varchar_key`,`col_int_key`) ); CREATE TABLE t2 LIKE t1; INSERT INTO t1 VALUES (10,7,8,NULL,NULL,'01:27:35','01:27:35','2002-02-26 06:14:37','2002-02-26 06:14:37','v','v'), (11,1,9,'2006-06-14','2006-06-14','19:48:31','19:48:31','1900-01-01 00:00:00','1900-01-01 00:00:00','r','r'); INSERT INTO t2 SELECT * FROM t1; SELECT table2.col_int_key AS field1 FROM ( t2 AS table1 RIGHT OUTER JOIN ( ( t1 AS table2 STRAIGHT_JOIN t1 AS table3 ON ( (table3.col_varchar_nokey = table2.col_varchar_key ) AND (table3.pk = table2.col_int_key)) ) ) ON ( (table3.col_varchar_key = table2.col_varchar_key) OR (table3.col_int_key = table2.pk) ) ) HAVING field1 < 216; DROP TABLE t1, t2; --echo # --echo # LPBUG#524025 Running RQG outer_join test leads to crash --echo # CREATE TABLE t0 ( pk int(11) NOT NULL AUTO_INCREMENT, PRIMARY KEY (pk) ); CREATE TABLE t1 ( col_int int(11) DEFAULT NULL, col_int_key int(11) DEFAULT NULL, pk int(11) NOT NULL AUTO_INCREMENT, col_varchar_10_latin1 varchar(10) DEFAULT NULL, PRIMARY KEY (pk) ); INSERT INTO t1 VALUES (5,5,1,'t'), (NULL,NULL,2,'y'); CREATE TABLE t2 ( col_int int(11) DEFAULT NULL ); INSERT INTO t2 VALUES (8), (4); CREATE TABLE t3 ( pk int(11) NOT NULL AUTO_INCREMENT, PRIMARY KEY (pk) ); INSERT INTO t3 VALUES (1),(8); CREATE TABLE t4 ( pk int(11) NOT NULL AUTO_INCREMENT, col_varchar_1024_latin1_key varchar(1024) DEFAULT NULL, col_int int(11) DEFAULT NULL, PRIMARY KEY (pk) ); INSERT INTO t4 VALUES (1,'o',1), (2,'w',2); CREATE TABLE t5 ( col_varchar_1024_utf8_key varchar(1024) CHARACTER SET utf8 DEFAULT NULL, col_varchar_1024_latin1_key varchar(1024) DEFAULT NULL, col_varchar_10_utf8_key varchar(1024) CHARACTER SET utf8 DEFAULT NULL, pk int(11) NOT NULL AUTO_INCREMENT, col_int_key int(11) DEFAULT NULL, PRIMARY KEY (pk) ); INSERT INTO t5 VALUES ('k','a','z',1,2),('x','a','w',2,7); CREATE TABLE t6 ( col_int int(11) DEFAULT NULL, col_int_key int(11) DEFAULT NULL ); INSERT INTO t6 VALUES (6,1),(8,3); SELECT table3.col_int AS field1, table1.col_int AS field2, table1.col_int_key AS field3, table1.pk AS field4, table1.col_int AS field5, table2.col_int AS field6 FROM t1 AS table1 LEFT OUTER JOIN t4 AS table2 LEFT JOIN t6 AS table3 RIGHT JOIN t3 AS table4 LEFT JOIN t5 AS table5 ON table4.pk = table5.pk LEFT JOIN t0 AS table6 ON table5.col_int_key = table6.pk ON table3.col_int_key = table5.pk ON table2.col_varchar_1024_latin1_key = table5.col_varchar_10_utf8_key LEFT JOIN t6 AS table7 ON table2.pk = table7.col_int ON table1.col_varchar_10_latin1 = table5.col_varchar_1024_latin1_key LEFT JOIN t2 AS table8 ON table3.col_int = table8.col_int WHERE table1.col_int_key < table2.pk HAVING field4 != 6; drop table t0,t1,t2,t3,t4,t5,t6; --echo # --echo # BUG#675118: Elimination of a table results in an invalid execution plan --echo # CREATE TABLE t1 (f1 int(11), PRIMARY KEY (f1)) ; CREATE TABLE t2 (f4 varchar(1024), KEY (f4)) ; INSERT IGNORE INTO t2 VALUES ('xcddwntkbxyorzdv'), ('cnxxcddwntkbxyor'),('r'),('r'), ('did'),('I'),('when'), ('hczkfqjeggivdvac'),('e'),('okay'),('up'); CREATE TABLE t3 (f4 varchar(1024), f1 int(11), f2 int(11)) ; INSERT IGNORE INTO t3 VALUES ('f','4','0'),('n','5','-996540416'); CREATE TABLE t4 (f1 int(11), f3 varchar(10)) ; INSERT IGNORE INTO t4 VALUES ('8','n'),('9','nwzcerzsgx'),('10','c'); CREATE TABLE t5 (f5 int(11), KEY (f5)) ; EXPLAIN SELECT t3.f2 FROM t2 LEFT JOIN t3 LEFT JOIN t4 LEFT JOIN t1 ON t4.f1 = t1.f1 JOIN t5 ON t4.f3 ON t3.f1 = t5.f5 ON t2.f4 = t3.f4 WHERE t3.f2 ; --echo # ^^ The above must not produce a QEP of t3,t5,t2,t4 --echo # as that violates the "no interleaving of outer join nests" rule. DROP TABLE t1,t2,t3,t4,t5; --echo # --echo # BUG#997747: Assertion `join->best_read < ((double)1.79..5e+308L)' --echo # failed in greedy_search with LEFT JOINs and unique keys --echo # CREATE TABLE t1 (a1 INT); CREATE TABLE t2 (b1 INT); CREATE TABLE t3 (c1 INT, UNIQUE KEY(c1)); CREATE TABLE t4 (d1 INT, UNIQUE KEY(d1)); CREATE TABLE t5 (e1 INT); INSERT INTO t1 VALUES (1),(2); INSERT INTO t2 VALUES (2),(3); INSERT INTO t3 VALUES (3),(4); INSERT INTO t4 VALUES (4),(5); INSERT INTO t5 VALUES (5),(6); SELECT a1 FROM t1 LEFT JOIN t2 LEFT JOIN t3 LEFT JOIN t4 ON c1 = d1 ON d1 = b1 ON a1 = b1 LEFT JOIN t5 ON a1 = e1 ; DROP TABLE t1,t2,t3,t4,t5; --echo # --echo # BUG#884184: Wrong result with RIGHT JOIN + derived_merge --echo # CREATE TABLE t1 (a int(11), b varchar(1)) ; INSERT IGNORE INTO t1 VALUES (0,'g'); CREATE TABLE t3 ( a varchar(1)) ; INSERT IGNORE INTO t3 VALUES ('g'); CREATE TABLE t2 ( a int(11) NOT NULL, PRIMARY KEY (a)); INSERT INTO t2 VALUES (9), (10); create view v1 as SELECT t1.* FROM t1 LEFT JOIN t2 ON ( t1.a = t2.a ) WHERE t2.a <> 0; SELECT alias1.* FROM t3 LEFT JOIN v1 as alias1 ON ( t3.a = alias1.b ); EXPLAIN SELECT alias1.* FROM t3 LEFT JOIN v1 as alias1 ON ( t3.a = alias1.b ); drop view v1; DROP TABLE t1,t2,t3; --echo # --echo # MDEV-5344: LEFT OUTER JOIN table data is lost in ON DUPLICATE KEY UPDATE section --echo # create table t1 ( id int(10) unsigned NOT NULL DEFAULT '0', v int(10) unsigned DEFAULT '0', PRIMARY KEY (id) ); create table t2 ( id int(10) unsigned NOT NULL DEFAULT '0', PRIMARY KEY (id) ) ; create table t3 ( id int(10) unsigned NOT NULL DEFAULT '0', v int(10) unsigned DEFAULT '0', PRIMARY KEY (id) ); insert into t1 values (1, 10), (2, 10); insert into t2 values (1), (2); insert into t3 values (1, 20); insert into t1 select t2.id, 5 from t2 LEFT OUTER JOIN t3 ON t2.id = t3.id on duplicate key update t1.v = t3.v; select * from t1; drop table t1,t2,t3; --echo # --echo # BUG#919878: Assertion `!eliminated_tables... --echo # CREATE TABLE t1 ( a INT ); INSERT INTO t1 VALUES (1); CREATE TABLE t2 ( b INT, UNIQUE INDEX(b) ); INSERT INTO t2 VALUES (1),(2); EXPLAIN EXTENDED SELECT * FROM t2 WHERE b IN ( SELECT SUM(a) FROM t1 LEFT JOIN t2 ON b=a ); DROP TABLE t1,t2; --echo # --echo # MDEV-4840: Wrong result (missing rows) on LEFT JOIN with InnoDB tables --echo # CREATE TABLE t1 (alpha3 VARCHAR(3)); INSERT INTO t1 VALUES ('USA'),('CAN'); CREATE TABLE t2 ( t3_code VARCHAR(3), name VARCHAR(64)); INSERT INTO t2 VALUES ('USA','Austin'),('USA','Boston'); CREATE TABLE t3 ( code VARCHAR(3), name VARCHAR(64), PRIMARY KEY (code), UNIQUE KEY (name)); INSERT INTO t3 VALUES ('CAN','Canada'),('USA','United States'); SELECT * FROM t1 LEFT JOIN ( t2 LEFT JOIN t3 ON t2.t3_code = t3.code ) ON t1.alpha3 = t3.code; SELECT t1.alpha3 FROM t1 LEFT JOIN ( t2 LEFT JOIN t3 ON t2.t3_code = t3.code ) ON t1.alpha3 = t3.code; DROP TABLE t1, t2, t3; SET optimizer_switch=@save_optimizer_switch; --echo # --echo # MDEV-7893: table_elimination works wrong with on computed expression and compound unique key --echo # (just a testcase) #enable after fix MDEV-28602 --disable_view_protocol CREATE TABLE t1 ( PostID int(10) unsigned NOT NULL ) DEFAULT CHARSET=utf8; INSERT INTO t1 (PostID) VALUES (1), (2); CREATE TABLE t2 ( VoteID int(10) unsigned NOT NULL PRIMARY KEY AUTO_INCREMENT, EntityID int(10) unsigned NOT NULL, UserID int(10) unsigned NOT NULL, UNIQUE KEY EntityID (EntityID,UserID) ) DEFAULT CHARSET=utf8; INSERT INTO t2 (EntityID, UserID) VALUES (1, 30), (2, 30); SELECT t1.*, T.Voted as Voted FROM t1 LEFT JOIN ( SELECT 1 AS Voted, EntityID FROM t2 WHERE t2.UserID = '20' ) AS T ON T.EntityID = t1.PostID WHERE t1.PostID='1' LIMIT 1; DROP TABLE t1,t2; --enable_view_protocol --echo # --echo # MDEV-26278: Table elimination does not work across derived tables --echo # create table t1 (a int, b int); insert into t1 select seq, seq+10 from seq_1_to_10; create table t11 ( a int not null, b int, key(a) ); insert into t11 select A.seq, A.seq+B.seq from seq_1_to_10 A, seq_1_to_100 B; create table t12 ( pk int primary key, col1 int ); insert into t12 select seq, seq from seq_1_to_1000; create view v2b as select t11.a as a, count(*) as b from t11 left join t12 on t12.pk=t11.b group by t11.a; --echo # The whole v2b is eliminated explain select t1.* from t1 left join v2b on v2b.a=t1.a; --echo # Check format JSON as well explain format=JSON select t1.* from t1 left join v2b on t1.a=v2b.a; --echo # Elimination of a whole subquery explain select t1.* from t1 left join (select t11.a as a, count(*) as b from t11 left join t12 on t12.pk=t11.b group by t11.a) v2b on v2b.a=t1.a; --echo # In this case v2b cannot be eliminated (since v2b.b is not unique)! explain select t1.* from t1 left join v2b on t1.a=v2b.b; --echo # Check format JSON as well explain format=JSON select t1.* from t1 left join v2b on t1.a=v2b.b; create view v2c as select t11.a as a, max(t12.col1) as b from t11 left join t12 on t12.pk=t11.b group by t11.a; --echo # The whole v2c is eliminated explain select t1.* from t1 left join v2c on v2c.a=t1.a; --echo # Check format JSON as well explain format=JSON select t1.* from t1 left join v2c on v2c.a=t1.a; --echo # In this case v2c cannot be eliminated (since v2c.b is not unique)! explain select t1.* from t1 left join v2c on t1.a=v2c.b; --echo # Check format JSON as well explain format=JSON select t1.* from t1 left join v2c on t1.a=v2c.b; --echo # Create a view with multiple fields in the GROUP BY clause: create view v2d as select t11.a as a, t11.b as b, max(t12.col1) as max_col1 from t11 left join t12 on t12.pk=t11.b group by t11.a, t11.b; --echo # This one must not be eliminated since only one of the GROUP BY fields is bound: explain select t1.* from t1 left join v2d on v2d.a=t1.a; --echo # This must be eliminated since both fields are bound: explain select t1.* from t1 left join v2d on v2d.a=t1.a and v2d.b=t1.b; create table t13 (dt date, b int); --echo # Function year() in the GROUP BY list prevents treating this field --echo # as a unique key create view v2e as select year(t13.dt) as yyy, max(t12.col1) as max_col1 from t13 join t12 on t12.pk=t13.b group by yyy; --echo # No elimination here since function year() is used explain select t1.* from t1 left join v2e on v2e.yyy=t1.a; create table t2 (a int, b int, c int); insert into t2 select A.seq, B.seq, 123 from seq_1_to_3 A, seq_1_to_3 B; --echo # No elimination here since not all fields of the derived table's --echo # GROUP BY are on the SELECT list so D.a is not unique explain select t1.* from t1 left join (select a, count(*) as cnt from t2 group by a, b) D on D.a=t1.a; --echo # Still no elimination 'cause field D.b is just an alias for t2.a explain select t1.* from t1 left join (select a, a as b, count(*) as cnt from t2 group by a, b) D on D.a=t1.a and D.b=t1.b; --echo # Now both a and b fields are on the SELECT list and they are bound to t1 --echo # so derived D must be eliminated explain select t1.* from t1 left join (select a as a1, b as b1, count(*) as cnt from t2 group by a, b) D on D.a1=t1.a and D.b1=t1.b; --echo # Different order of fields in GROUP BY and SELECT lists --echo # must not hamper the elimination explain select t1.* from t1 left join (select count(*) as cnt, b, a from t2 group by a, b) D on D.a=t1.a and D.b=t1.b; drop view v2b, v2c, v2d, v2e; drop table t1, t11, t12, t13, t2; --echo # --echo # End of MDEV-26278: Table elimination does not work across derived tables --echo # --echo # --echo # MDEV-28881: Server crashes in Dep_analysis_context::create_table_value/ --echo # check_func_dependency --echo # CREATE TABLE t1 (a1 int, a2 int); INSERT INTO t1 VALUES (0,276),(5,277),(NULL,278); CREATE TABLE t2 ( a1 int, a2 int, KEY a2 (a2)); INSERT INTO t2 VALUES (11,NULL),(185,0); SELECT t1.* FROM t1 LEFT JOIN ( SELECT * FROM (SELECT t2.a1 AS a1, min(t2.a2) AS a2 FROM t2 WHERE t2.a2 <> NULL GROUP BY t2.a1) dt ) dt2 ON dt2.a2 = t1.a2; DROP TABLE t1, t2; --echo # --echo # MDEV-30007: SIGSEGV in st_select_lex_unit::is_derived_eliminated, --echo # runtime error: member access within null pointer of type --echo # 'struct TABLE' in st_select_lex_unit::is_derived_eliminated() --echo # CREATE VIEW v AS SELECT 1 AS a; SELECT ROUND ((SELECT 1 FROM v)) FROM v GROUP BY ROUND ((SELECT 1 FROM v)); EXPLAIN SELECT ROUND ((SELECT 1 FROM v)) FROM v GROUP BY ROUND ((SELECT 1 FROM v)); DROP VIEW v; --echo # --echo # End of 10.10 tests --echo #