mariadb/mysql-test/r/subselect2.result
unknown 5f97dc6e9e BUG#24127: (a,b) IN (SELECT c,d ...) can produce wrong results if a and/or b are NULLs:
- Make the code produce correct result: use an array of triggers to turn on/off equalities for each
  compared column. Also turn on/off optimizations based on those equalities.
- Make EXPLAIN output show "Full scan on NULL key" for tables for which we switch between
  ref/unique_subquery/index_subquery and ALL access.
- index_subquery engine now has HAVING clause when it is needed, and it is
  displayed in EXPLAIN EXTENDED
- Fix incorrect presense of "Using index" for index/unique-based subqueries (BUG#22930)
// bk trigger note: this commit refers to BUG#24127


mysql-test/r/ndb_subquery.result:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Updated test results (checked)
mysql-test/r/subselect.result:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Updated test results (checked)
mysql-test/r/subselect2.result:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Updated test results (checked)
mysql-test/r/subselect3.result:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Testcases
mysql-test/t/subselect3.test:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Testcases
sql/item_cmpfunc.cc:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - For row-based IN subqueries, use one flag per each column. Set the flags appropriately before
    running the subquery.
sql/item_cmpfunc.h:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
   - Added Item_func_trig_cond::get_triv_var()
sql/item_subselect.cc:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Item_subselect::exec() and subselect_*_engine::exec() don't have parameter
    anymore - now Item_subselect owns the pushed down predicates guard flags.
  - A correct set of conditional predicates is now pushed into row-based IN 
    subquery.
  - select_indexsubquery_engine now has "HAVING clause" (needed for correct query
    results), and it is shown in EXPLAIN EXTENDED
sql/item_subselect.h:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Item_subselect::exec() and subselect_*_engine::exec() don't have parameter
    anymore - now Item_subselect owns the pushed down predicates guard flags.
  - A correct set of conditional predicates is now pushed into row-based IN 
    subquery.
  - select_indexsubquery_engine now has "HAVING clause" (needed for correct query
    results), and it is shown in EXPLAIN EXTENDED
sql/mysql_priv.h:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Added "in_having_cond" special Item name
sql/mysqld.cc:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Added "in_having_cond" special Item name
sql/sql_lex.h:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
sql/sql_select.cc:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Make "ref" analyzer be able to work with conditional equalities
  - Fix subquery optimization code to match the changes in what kinds of 
    conditions are pushed down into subqueries 
  - Fix wrong EXPLAIN output in some queries with subquery (BUG#22390)
sql/sql_select.h:
  BUG#24127: wrong result for (null,not-null) IN (SELECT a,b ...)
  - Make "ref" analyzer be able to work with conditional equalities
  - Fix wrong EXPLAIN output in some queries with subquery (BUG#22390)
2007-01-12 23:22:41 +03:00

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drop table if exists t1, t2, t3, t4;
CREATE TABLE t1
(
DOCID VARCHAR(32)BINARY NOT NULL
, UUID VARCHAR(32)BINARY NOT NULL
, MIMETYPE VARCHAR(80)BINARY
, CONTENTDATA LONGBLOB
, CONTENTSIZE INTEGER
, VERSIONID INTEGER
, REPID VARCHAR(32)BINARY
, MODIFIED TIMESTAMP
, MODIFIER VARCHAR(255)BINARY
, ORIGINATOR INTEGER
, PRIMARY KEY ( DOCID )
) ENGINE=InnoDB
;
INSERT INTO t1 (DOCID) VALUES ("1"), ("2");
Warnings:
Warning 1364 Field 'UUID' doesn't have a default value
CREATE TABLE t2
(
DOCID VARCHAR(32)BINARY NOT NULL
, DOCNAME VARCHAR(255)BINARY NOT NULL
, DOCTYPEID VARCHAR(32)BINARY NOT NULL
, FOLDERID VARCHAR(32)BINARY NOT NULL
, AUTHOR VARCHAR(255)BINARY
, CREATED TIMESTAMP NOT NULL
, TITLE VARCHAR(255)BINARY
, SUBTITLE VARCHAR(255)BINARY
, DOCABSTRACT LONGBLOB
, PUBLISHDATE TIMESTAMP
, EXPIRATIONDATE TIMESTAMP
, LOCKEDBY VARCHAR(80)BINARY
, STATUS VARCHAR(80)BINARY
, PARENTDOCID VARCHAR(32)BINARY
, REPID VARCHAR(32)BINARY
, MODIFIED TIMESTAMP NOT NULL
, MODIFIER VARCHAR(255)BINARY NOT NULL
, PUBLISHSTATUS INTEGER
, ORIGINATOR INTEGER
, PRIMARY KEY ( DOCID )
) ENGINE=InnoDB
;
CREATE INDEX DDOCTYPEID_IDX ON t2 (DOCTYPEID);
CREATE INDEX DFOLDERID_IDX ON t2 (FOLDERID);
CREATE TABLE t3
(
FOLDERID VARCHAR(32)BINARY NOT NULL
, FOLDERNAME VARCHAR(255)BINARY NOT NULL
, CREATOR VARCHAR(255)BINARY
, CREATED TIMESTAMP NOT NULL
, DESCRIPTION VARCHAR(255)BINARY
, FOLDERTYPE INTEGER NOT NULL
, MODIFIED TIMESTAMP
, MODIFIER VARCHAR(255)BINARY
, FOLDERSIZE INTEGER NOT NULL
, PARENTID VARCHAR(32)BINARY
, REPID VARCHAR(32)BINARY
, ORIGINATOR INTEGER
, PRIMARY KEY ( FOLDERID )
) ENGINE=InnoDB;
CREATE INDEX FFOLDERID_IDX ON t3 (FOLDERID);
CREATE INDEX CMFLDRPARNT_IDX ON t3 (PARENTID);
CREATE TABLE t4
(
DOCTYPEID VARCHAR(32)BINARY NOT NULL
, DOCTYPENAME VARCHAR(80)BINARY NOT NULL
, DESCRIPTION VARCHAR(255)BINARY
, EXTNDATA LONGBLOB
, MODIFIED TIMESTAMP
, MODIFIER VARCHAR(255)BINARY
, ORIGINATOR INTEGER
, PRIMARY KEY ( DOCTYPEID )
) ENGINE=InnoDB;
INSERT INTO t2 VALUES("c373e9f59cf15a6c3e57444553544200", "c373e9f59cf15a6c3e57444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-06 07:48:42", NULL, NULL, NULL, "2003-06-06 07:48:42", "2003-06-06 07:48:42", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-06 07:48:42", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5a472f43ba45e444553544200", "c373e9f5a472f43ba45e444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-07 18:50:12", NULL, NULL, NULL, "2003-06-07 18:50:12", "2003-06-07 18:50:12", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-07 18:50:12", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5a4a0f56014eb444553544200", "c373e9f5a4a0f56014eb444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-07 19:39:26", NULL, NULL, NULL, "2003-06-07 19:39:26", "2003-06-07 19:39:26", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-07 19:39:26", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5a4a0f8fa4a86444553544200", "c373e9f5a4a0f8fa4a86444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-07 19:43:05", NULL, NULL, NULL, "2003-06-07 19:43:05", "2003-06-07 19:43:05", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-07 19:43:05", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5ac7b537205ce444553544200", "c373e9f5ac7b537205ce444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-09 08:15:24", NULL, NULL, NULL, "2003-06-09 08:15:24", "2003-06-09 08:15:24", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-09 08:15:24", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5ad0792012454444553544200", "c373e9f5ad0792012454444553544200", "340d243d45f111d497b00010a4ef934d", "2f6161e879db43c1a5b82c21ddc49089", NULL, "2003-06-09 10:51:44", NULL, NULL, NULL, "2003-06-09 10:51:44", "2003-06-09 10:51:44", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-09 10:51:44", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5ad079821ef34444553544200", "First Discussion", "c373e9f5ad079174ff17444553544200", "c373e9f5ad0796c0eca4444553544200", "Goldilocks", "2003-06-09 11:16:50", "Title: First Discussion", NULL, NULL, "2003-06-09 10:51:26", "2003-06-09 10:51:26", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-09 11:16:50", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5ad07993f3859444553544200", "Last Discussion", "c373e9f5ad079174ff17444553544200", "c373e9f5ad0796c0eca4444553544200", "Goldilocks", "2003-06-09 11:21:06", "Title: Last Discussion", NULL, "Setting new abstract and keeping doc checked out", "2003-06-09 10:51:26", "2003-06-09 10:51:26", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-09 11:21:06", "admin", "0", NULL);
INSERT INTO t2 VALUES("c373e9f5ad079a3219c4444553544200", "testdoclayout", "340d243c45f111d497b00010a4ef934d", "c373e9f5ad0796c0eca4444553544200", "Goldilocks", "2003-06-09 11:25:31", "Title: Test doc layout", "Subtitle: test doc layout", NULL, "2003-06-09 10:51:27", "2003-06-09 10:51:27", NULL, NULL, NULL, "03eea05112b845949f3fd03278b5fe43", "2003-06-09 11:25:31", "admin", "0", NULL);
INSERT INTO t3 VALUES("0c9aab05b15048c59bc35c8461507deb", "System", "System", "2003-06-05 16:30:00", "The system content repository folder.", "3", "2003-06-05 16:30:00", "System", "0", NULL, "9c9aab05b15048c59bc35c8461507deb", "1");
INSERT INTO t3 VALUES("2f6161e879db43c1a5b82c21ddc49089", "Default", "System", "2003-06-09 10:52:02", "The default content repository folder.", "3", "2003-06-05 16:30:00", "System", "0", NULL, "03eea05112b845949f3fd03278b5fe43", "1");
INSERT INTO t3 VALUES("c373e9f5ad0791724315444553544200", "AddDocumentTest", "admin", "2003-06-09 10:51:25", "Movie Reviews", "0", "2003-06-09 10:51:25", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad07919e1963444553544200", "NewDestDirectory", "admin", "2003-06-09 10:51:28", "Adding new directory", "128", "2003-06-09 10:51:28", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad07919fe525444553544200", "SubDestDirectory", "admin", "2003-06-09 10:51:28", "Adding new directory", "128", "2003-06-09 10:51:28", "admin", "0", "c373e9f5ad07919e1963444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a0dab5444553544200", "Level1", "admin", "2003-06-09 10:51:29", NULL, "0", "2003-06-09 10:51:29", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a14669444553544200", "Level2", "admin", "2003-06-09 10:51:29", NULL, "0", "2003-06-09 10:51:29", "admin", "0", "c373e9f5ad0791a0dab5444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a23c0e444553544200", "Level3", "admin", "2003-06-09 10:51:29", NULL, "0", "2003-06-09 10:51:29", "admin", "0", "c373e9f5ad0791a14669444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a6b11f444553544200", "Dir1", "admin", "2003-06-09 10:51:30", NULL, "0", "2003-06-09 10:51:30", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a897d6444553544200", "Dir2", "admin", "2003-06-09 10:51:30", NULL, "0", "2003-06-09 10:51:30", "admin", "0", "c373e9f5ad0791a6b11f444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791a9a063444553544200", "NewDestDirectory", "admin", "2003-06-09 10:51:31", NULL, "0", "2003-06-09 10:51:31", "admin", "0", "c373e9f5ad0791a897d6444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791aa73e3444553544200", "LevelA", "admin", "2003-06-09 10:51:31", NULL, "0", "2003-06-09 10:51:31", "admin", "0", "c373e9f5ad0791a0dab5444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791ab034b444553544200", "LevelB", "admin", "2003-06-09 10:51:31", NULL, "0", "2003-06-09 10:51:31", "admin", "0", "c373e9f5ad0791aa73e3444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791ac7311444553544200", "LevelC", "admin", "2003-06-09 10:51:32", NULL, "0", "2003-06-09 10:51:32", "admin", "0", "c373e9f5ad0791ab034b444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791ad66cf444553544200", "test2", "admin", "2003-06-09 10:51:32", NULL, "0", "2003-06-09 10:51:32", "admin", "0", "c373e9f5ad0791724315444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791aebd87444553544200", "test3", "admin", "2003-06-09 10:51:33", NULL, "0", "2003-06-09 10:51:33", "admin", "0", "c373e9f5ad0791ad66cf444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0791dbaac4444553544200", "Special Caf<61> Folder", "admin", "2003-06-09 10:51:43", "test folder names with special chars", "0", "2003-06-09 10:51:43", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0796bf913f444553544200", "CopiedFolder", "admin", "2003-06-09 11:09:05", "Movie Reviews", "0", "2003-06-09 11:09:05", "admin", "0", "c373e9f5ad0791a23c0e444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0796c0eca4444553544200", "Movie Reviews", "admin", "2003-06-09 11:09:13", "Movie Reviews", "0", "2003-06-09 11:09:13", "admin", "33", "c373e9f5ad0796bf913f444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad0796d9b895444553544200", "NewBookFolder", "admin", "2003-06-09 11:12:41", "NewBooks - folder", "0", "2003-06-09 11:12:41", "admin", "0", "c373e9f5ad0796c0eca4444553544200", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t3 VALUES("c373e9f5ad079b4c9355444553544200", "CopiedFolder", "admin", "2003-06-09 11:26:34", "Movie Reviews", "0", "2003-06-09 11:26:34", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
INSERT INTO t4 VALUES("340d243c45f111d497b00010a4ef934d", "Document Layout", "The system Document Layouts Document Type", NULL, "2003-06-05 16:30:00", "System", "1");
INSERT INTO t4 VALUES("340d243d45f111d497b00010a4ef934d", "Default", "The default system Document Type", NULL, "2003-06-05 16:30:00", "System", "1");
INSERT INTO t4 VALUES("4d09dd60850711d4998a204c4f4f5020", "__SystemResourceType", "The type for all the uploaded resources", NULL, "2003-06-05 16:30:00", "System", "1");
INSERT INTO t4 VALUES("91d4d595478211d497b40010a4ef934d", "__PmcSystemDefaultType", "The type for all the default available fields", NULL, "2003-06-05 16:30:00", "System", "1");
INSERT INTO t4 VALUES("c373e9f59cf15a59b08a444553544200", "NoFieldDocType", "plain doc type", NULL, "2003-06-06 07:48:40", "admin", NULL);
INSERT INTO t4 VALUES("c373e9f59cf15a5c6a99444553544200", "Movie Review", "This doc type is for movie reviews", "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<props autocheckin=\"false\" autopublish=\"false\" binary=\"choice\" categories=\"none\" cleanup=\"false\" folder=\"none\"><![CDATA[Doc type for cm tests]]></props>\r\n", "2003-06-06 07:48:40", "admin", NULL);
INSERT INTO t4 VALUES("c373e9f59cf15a6116a5444553544200", "Special Doc<6F>u20A4u20A4u0113<31><33><EFBFBD><EFBFBD>u016BType", "test special chars xxx<78> in doc type", NULL, "2003-06-06 07:48:41", "admin", NULL);
INSERT INTO t4 VALUES("c373e9f59cf15a695d47444553544200", "Movie", NULL, NULL, "2003-06-06 07:48:41", "admin", NULL);
INSERT INTO t4 VALUES("c373e9f5ad079174ff17444553544200", "Discussion", NULL, NULL, "2003-06-09 10:51:25", "admin", NULL);
INSERT INTO t4 VALUES("c373e9f5ad0791da7e2b444553544200", "Books", "list of recommended books", "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<props autocheckin=\"false\" autopublish=\"false\" binary=\"choice\" categories=\"none\" cleanup=\"false\" folder=\"none\"><![CDATA[Doc type for cm tests]]><![CDATA[Doc type for book tests]]></props>\r\n", "2003-06-09 10:51:40", "admin", NULL);
ALTER TABLE t2 ADD FOREIGN KEY FK_DCMNTS_DCTYPES ( DOCTYPEID)
REFERENCES t4 (DOCTYPEID );
ALTER TABLE t2 ADD FOREIGN KEY FK_DCMNTS_FLDRS ( FOLDERID)
REFERENCES t3 (FOLDERID );
ALTER TABLE t3 ADD FOREIGN KEY FK_FLDRS_PRNTID ( PARENTID)
REFERENCES t3 (FOLDERID );
SELECT t2.*, t4.DOCTYPENAME, t1.CONTENTSIZE,t1.MIMETYPE FROM t2 INNER JOIN t4 ON t2.DOCTYPEID = t4.DOCTYPEID LEFT OUTER JOIN t1 ON t2.DOCID = t1.DOCID WHERE t2.FOLDERID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t3.FOLDERNAME = 'Level1') AND t3.FOLDERNAME = 'Level2') AND t3.FOLDERNAME = 'Level3') AND t3.FOLDERNAME = 'CopiedFolder') AND t3.FOLDERNAME = 'Movie Reviews') AND t2.DOCNAME = 'Last Discussion';
DOCID DOCNAME DOCTYPEID FOLDERID AUTHOR CREATED TITLE SUBTITLE DOCABSTRACT PUBLISHDATE EXPIRATIONDATE LOCKEDBY STATUS PARENTDOCID REPID MODIFIED MODIFIER PUBLISHSTATUS ORIGINATOR DOCTYPENAME CONTENTSIZE MIMETYPE
c373e9f5ad07993f3859444553544200 Last Discussion c373e9f5ad079174ff17444553544200 c373e9f5ad0796c0eca4444553544200 Goldilocks 2003-06-09 11:21:06 Title: Last Discussion NULL Setting new abstract and keeping doc checked out 2003-06-09 10:51:26 2003-06-09 10:51:26 NULL NULL NULL 03eea05112b845949f3fd03278b5fe43 2003-06-09 11:21:06 admin 0 NULL Discussion NULL NULL
EXPLAIN SELECT t2.*, t4.DOCTYPENAME, t1.CONTENTSIZE,t1.MIMETYPE FROM t2 INNER JOIN t4 ON t2.DOCTYPEID = t4.DOCTYPEID LEFT OUTER JOIN t1 ON t2.DOCID = t1.DOCID WHERE t2.FOLDERID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID IN(SELECT t3.FOLDERID FROM t3 WHERE t3.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t3.FOLDERNAME = 'Level1') AND t3.FOLDERNAME = 'Level2') AND t3.FOLDERNAME = 'Level3') AND t3.FOLDERNAME = 'CopiedFolder') AND t3.FOLDERNAME = 'Movie Reviews') AND t2.DOCNAME = 'Last Discussion';
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL DDOCTYPEID_IDX NULL NULL NULL 9 Using where
1 PRIMARY t1 eq_ref PRIMARY PRIMARY 34 test.t2.DOCID 1
1 PRIMARY t4 eq_ref PRIMARY PRIMARY 34 test.t2.DOCTYPEID 1
2 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX PRIMARY 34 func 1 Using where
3 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX PRIMARY 34 func 1 Using where
4 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX PRIMARY 34 func 1 Using where
5 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX PRIMARY 34 func 1 Using where
6 DEPENDENT SUBQUERY t3 unique_subquery PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 func 1 Using where
drop table t1, t2, t3, t4;
CREATE TABLE t1 (a int(10) , PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t1 VALUES (1),(2);
CREATE TABLE t2 (a int(10), PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t2 VALUES (1);
CREATE TABLE t3 (a int(10), b int(10), c int(10),
PRIMARY KEY (a)) Engine=InnoDB;
INSERT INTO t3 VALUES (1,2,1);
SELECT t1.* FROM t1 WHERE (SELECT COUNT(*) FROM t3,t2 WHERE t3.c=t2.a
and t2.a='1' AND t1.a=t3.b) > 0;
a
2
DROP TABLE t1,t2,t3;