summaryrefslogtreecommitdiff
path: root/mysql-test/t/subselect_innodb.test
blob: 307493bc0e4dfacce9c3e0191de156a67d985dbe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
-- source include/have_innodb.inc

# Note: the tests uses only non-semijoin subqueries so semi-join switch
#       settings are not relevant.
set @subselect_innodb_tmp=@@optimizer_switch;
set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
--disable_warnings
drop table if exists t1,t2,t3;
--enable_warnings

#
# key field overflow test
#
SET sql_mode = 'NO_ENGINE_SUBSTITUTION';
CREATE TABLE t1
(
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 t1 (FOLDERID);
CREATE INDEX CMFLDRPARNT_IDX ON t1 (PARENTID);
SET sql_mode = DEFAULT;
INSERT INTO t1 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 t1 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 t1 VALUES("c373e9f5ad0791724315444553544200", "AddDocumentTest", "admin", "2003-06-09 10:51:25", "Movie Reviews", "0", "2003-06-09 10:51:25", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
SELECT 'c373e9f5ad0791a0dab5444553544200' IN(SELECT t1.FOLDERID FROM t1 WHERE t1.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t1.FOLDERNAME = 'Level1');
drop table t1;

#
# UNION unlocking test
#
create table t1 (a int) engine=innodb;
create table t2 (a int) engine=innodb;
create table t3 (a int) engine=innodb;
insert into t1 values (1),(2),(3),(4);
insert into t2 values (10),(20),(30),(40);
insert into t3 values (1),(2),(10),(50);
select a from t3 where t3.a in (select a from t1 where a <= 3 union select * from t2 where a <= 30);
drop table t1,t2,t3;


CREATE TABLE t1 (
   processor_id INTEGER NOT NULL,
   PRIMARY KEY (processor_id)
) ENGINE=InnoDB;
CREATE TABLE t3 (
   yod_id BIGINT UNSIGNED AUTO_INCREMENT NOT NULL,
   login_processor INTEGER UNSIGNED ,
   PRIMARY KEY (yod_id)
) ENGINE=InnoDB;
CREATE TABLE t2 (
   processor_id INTEGER NOT NULL,
   yod_id BIGINT UNSIGNED NOT NULL,
   PRIMARY KEY (processor_id, yod_id),
   INDEX (processor_id),
   INDEX (yod_id),
   FOREIGN KEY (processor_id) REFERENCES t1(processor_id),
   FOREIGN KEY (yod_id) REFERENCES t3(yod_id) 
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1),(2),(3);
INSERT INTO t3 VALUES (1,1),(2,2),(3,3);
INSERT INTO t2 VALUES (1,1),(2,2),(3,3);
SELECT distinct p1.processor_id, (SELECT y.yod_id FROM t1 p2, t2 y WHERE p2.processor_id = p1.processor_id and p2.processor_id = y.processor_id) FROM t1 p1;
drop table t2,t1,t3;

#
# innodb locking
#
CREATE TABLE t1 (
  id int(11) NOT NULL default '0',
  b int(11) default NULL,
  c char(3) default NULL,
  PRIMARY KEY  (id),
  KEY t2i1 (b)
) ENGINE=innodb DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES (0,0,'GPL'),(1,0,'GPL'),(2,1,'GPL'),(3,2,'GPL');
CREATE TABLE t2 (
  id int(11) NOT NULL default '0',
  b int(11) default NULL,
  c char(3) default NULL,
  PRIMARY KEY  (id),
  KEY t2i (b)
) ENGINE=innodb DEFAULT CHARSET=latin1;
INSERT INTO t2 VALUES (0,0,'GPL'),(1,0,'GPL'),(2,1,'GPL'),(3,2,'GPL');
select (select max(id) from t2 where b=1 group by b) as x,b from t1 where b=1;
drop table t1,t2;

#
# reiniting innodb tables
#
create table t1 (id int not null, value char(255), primary key(id)) engine=innodb;
create table t2 (id int not null, value char(255)) engine=innodb;
insert into t1 values (1,'a'),(2,'b');
insert into t2 values (1,'z'),(2,'x');
select t2.id,t2.value,(select t1.value from t1 where t1.id=t2.id) from t2;
select t2.id,t2.value,(select t1.value from t1 where t1.id=t2.id) from t2;
drop table t1,t2;

#
# unlocking tables with subqueries in HAVING
#
create table t1 (a int, b int) engine=innodb;
insert into t1 values (1,2), (1,3), (2,3), (2,4), (2,5), (3,4), (4,5), (4,100);
create table t2 (a int) engine=innodb;
insert into t2 values (1),(2),(3),(4);
select a, sum(b) as b from t1 group by a having b > (select max(a) from t2);
drop table t1, t2;

#
# bug #5220 test suite
#
CREATE TABLE `t1` ( `unit` varchar(50) NOT NULL default '', `ingredient` varchar(50) NOT NULL default '') ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `t2` ( `ingredient` varchar(50) NOT NULL default '', `unit` varchar(50) NOT NULL default '', PRIMARY KEY (ingredient, unit)) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `t1` VALUES ('xx','yy');
INSERT INTO `t2` VALUES ('yy','xx');

SELECT R.unit, R.ingredient FROM t1 R WHERE R.ingredient IN (SELECT N.ingredient FROM t2 N WHERE N.unit = R.unit);

drop table t1, t2;

#
# possible early unlock
#
CREATE TABLE t1 (
  id INT NOT NULL auto_increment,
  date1 DATE, coworkerid INT,
  description VARCHAR(255),
  sum_used DOUBLE,
  sum_remaining DOUBLE,
  comments VARCHAR(255),
  PRIMARY KEY(id)
) engine=innodb;
insert into t1 values (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1998-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1998-01-01', 1,'test', 22, 33, 'comment'), (NULL, '2004-01-01', 1,'test', 22, 33, 'comment'), (NULL, '2004-01-01', 1,'test', 22, 33, 'comment');
SELECT DISTINCT
 (SELECT sum(sum_used) FROM t1 WHERE sum_used > 0 AND year(date1) <= '2004') as somallontvangsten,
 (SELECT sum(sum_used) FROM t1 WHERE sum_used < 0 AND year(date1) <= '2004') as somalluitgaven
 FROM t1;
select * from t1;
drop table t1;

#
# cleaning up of results of subselects (BUG#8125)
#
CREATE TABLE `t1` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY  (`a`,`b`,`c`)) ENGINE=InnoDB;
CREATE TABLE t2 LIKE t1;
INSERT INTO t1 VALUES (1,1,1);
INSERT INTO t2 VALUES (1,1,1);
PREPARE my_stmt FROM "SELECT t1.b, count(*) FROM t1 group by t1.b having
count(*) > ALL (SELECT COUNT(*) FROM t2 WHERE t2.a=1 GROUP By t2.b)";
EXECUTE my_stmt;
EXECUTE my_stmt;
deallocate prepare my_stmt;
drop table t1,t2;

# End of 4.1 tests

CREATE TABLE t1 (
  school_name varchar(45) NOT NULL,
  country varchar(45) NOT NULL,    
  funds_requested float NOT NULL,
  schooltype varchar(45) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

insert into t1 values ("the school", "USA", 1200, "Human");

select count(country) as countrycount, sum(funds_requested) as smcnt,
       country, (select sum(funds_requested) from t1) as total_funds
from t1
group by country;

select count(country) as countrycount, sum(funds_requested) as smcnt,
       country, (select sum(funds_requested) from t1) as total_funds
from t1
group by country;

drop table t1;

#
# BUG#14342: wrong placement of subquery internals in complex queries
#
CREATE TABLE `t1` (
  `t3_id` int NOT NULL,
  `t1_id` int NOT NULL,
  PRIMARY KEY  (`t1_id`)
);
CREATE TABLE `t2` (
  `t2_id` int NOT NULL,
  `t1_id` int NOT NULL,
  `b` int NOT NULL,
  PRIMARY KEY  (`t2_id`),
  UNIQUE KEY `idx_t2_t1_b` (`t1_id`,`b`)
) ENGINE=InnoDB;
CREATE TABLE `t3` (
  `t3_id` int NOT NULL
);
INSERT INTO `t3` VALUES (3);
select
  (SELECT rs.t2_id
   FROM t2 rs
   WHERE rs.t1_id=
     (SELECT lt.t1_id
      FROM t1 lt
      WHERE lt.t3_id=a.t3_id)
   ORDER BY b DESC LIMIT 1)
from t3 AS a;
# repeat above query in SP
--disable_warnings
DROP PROCEDURE IF EXISTS p1;
--enable_warnings
delimiter //;
create procedure p1()
begin
  declare done int default 3;
  repeat
    select
      (SELECT rs.t2_id
       FROM t2 rs
       WHERE rs.t1_id=
         (SELECT lt.t1_id
          FROM t1 lt
          WHERE lt.t3_id=a.t3_id)
       ORDER BY b DESC LIMIT 1) as x
    from t3 AS a;
    set done= done-1;
  until done <= 0 end repeat;
end//
delimiter ;//
call p1();
call p1();
call p1();
drop procedure p1;
drop tables t1,t2,t3;

--echo #
--echo # Bug #58756
--echo # Crash in heap_rrnd on query with HAVING ... IN (subquery) + LIMIT
--echo #

CREATE TABLE t1 (
  col_time_key time DEFAULT NULL,
  col_datetime_key datetime DEFAULT NULL,
  col_varchar_nokey varchar(1) DEFAULT NULL,
  KEY col_time_key (col_time_key),
  KEY col_datetime_key (col_datetime_key)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO t1 VALUES ('17:53:30','2005-11-10 12:40:29','h');
INSERT INTO t1 VALUES ('11:35:49','2009-04-25 00:00:00','b');
INSERT INTO t1 VALUES (NULL,'2002-11-27 00:00:00','s');
INSERT INTO t1 VALUES ('06:01:40','2004-01-26 20:32:32','e');
INSERT INTO t1 VALUES ('05:45:11','2007-10-26 11:41:40','j');
INSERT INTO t1 VALUES ('00:00:00','2005-10-07 00:00:00','e');
INSERT INTO t1 VALUES ('00:00:00','2000-07-15 05:00:34','f');
INSERT INTO t1 VALUES ('06:11:01','2000-04-03 16:33:32','v');
INSERT INTO t1 VALUES ('13:02:46',NULL,'x');
INSERT INTO t1 VALUES ('21:44:25','2001-04-25 01:26:12','m');
INSERT INTO t1 VALUES ('22:43:58','2000-12-27 00:00:00','c');

CREATE TABLE t2 (
  col_time_key time DEFAULT NULL,
  col_datetime_key datetime DEFAULT NULL,
  col_varchar_nokey varchar(1) DEFAULT NULL,
  KEY col_time_key (col_time_key),
  KEY col_datetime_key (col_datetime_key)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO t2 VALUES ('11:28:45','2004-10-11 18:13:16','w');

SELECT col_time_key, col_datetime_key
FROM 
( SELECT * FROM t1 ) AS table1 
HAVING ( 'r' , 'e' ) IN 
  ( SELECT col_varchar_nokey , col_varchar_nokey FROM t2 )
ORDER BY col_datetime_key 
LIMIT 10;

DROP TABLE t1;
DROP TABLE t2;

--echo # End of Bug #58756

--echo #
--echo # Bug#60085 crash in Item::save_in_field() with time data type
--echo #

CREATE TABLE t1(a date, b int, unique(b), unique(a), key(b)) engine=innodb;
INSERT INTO t1 VALUES ('2011-05-13', 0);
SELECT * FROM t1 WHERE b < (SELECT CAST(a as date) FROM t1 GROUP BY a); 
DROP TABLE t1;

--echo #
--echo # Bug #11766300  59387: FAILING ASSERTION: CURSOR->POS_STATE == 1997660512 (BTR_PCUR_IS_POSITIONE
--echo #

CREATE TABLE t1 (a INT) ENGINE=INNODB;
INSERT INTO t1 VALUES (0);
CREATE TABLE t2 (d BINARY(2), PRIMARY KEY (d(1)), UNIQUE KEY (d)) ENGINE=INNODB;

SELECT 1 FROM t1 WHERE NOT EXISTS
(SELECT 1 FROM t2 WHERE d = (SELECT d FROM t2 WHERE a >= 1) ORDER BY d);

EXPLAIN SELECT 1 FROM t1 WHERE NOT EXISTS
(SELECT 1 FROM t2 WHERE d = (SELECT d FROM t2 WHERE a >= 1) ORDER BY d);

DROP TABLE t2;

CREATE TABLE t2 (b INT, c INT, UNIQUE KEY (b), UNIQUE KEY (b, c )) ENGINE=INNODB;
INSERT INTO t2 VALUES (1, 1);

SELECT 1 FROM t1
WHERE a != (SELECT 1 FROM t2 WHERE a <=> b OR a > '' AND 6 = 7 ORDER BY b, c);

DROP TABLE t1, t2;

--echo #
--echo # Bug #13639204 64111: CRASH ON SELECT SUBQUERY WITH NON UNIQUE
--echo # INDEX
--echo #
CREATE TABLE t1 (
id int
) ENGINE=InnoDB;
INSERT INTO t1 (id) VALUES (11);

CREATE TABLE t2 (
t1_id int,
position int,
KEY t1_id (t1_id),
KEY t1_id_position (t1_id,position)
) ENGINE=InnoDB;

let $query=SELECT
(SELECT position FROM t2
WHERE t2.t1_id = t1.id
ORDER BY t2.t1_id , t2.position
LIMIT 10,1
) AS maxkey
FROM t1
LIMIT 1;

eval EXPLAIN $query;
eval $query;

DROP TABLE t1,t2;

--echo End of 5.1 tests

--echo #
--echo # lp:827416 Crash in select_describe() on EXPLAIN with DISTINCT in nested subqueries
--echo #

CREATE TABLE t3 ( b int) ENGINE=InnoDB;
CREATE TABLE t2 ( c int) ENGINE=InnoDB;
CREATE TABLE t1 ( a int NOT NULL , PRIMARY KEY (a)) ENGINE=InnoDB;

EXPLAIN SELECT *
FROM t1
WHERE t1.a = (
        SELECT SUM( c )
        FROM t2
        WHERE (SELECT DISTINCT b FROM t3) > 0);
SELECT *
FROM t1
WHERE t1.a = (
        SELECT SUM( c )
        FROM t2
        WHERE (SELECT DISTINCT b FROM t3) > 0);

DROP TABLE t1, t2, t3;


--echo #
--echo # lp:858148 Fourth crash in select_describe() with nested subqueries
--echo #

CREATE TABLE t1 ( f1 int(11)) ENGINE=InnoDB;
CREATE TABLE t2 ( f1 int(11), f2 int(11), PRIMARY KEY (f1)) ;
CREATE TABLE t3 ( f3 int(11)) ENGINE=InnoDB;

EXPLAIN
SELECT MAX( f1 ) FROM t2
WHERE f2 >= (
        SELECT SUM( f1 )
        FROM t1
        WHERE EXISTS (
                SELECT f3
                FROM t3
                GROUP BY 1
        )
);

SELECT MAX( f1 ) FROM t2
WHERE f2 >= (
        SELECT SUM( f1 )
        FROM t1
        WHERE EXISTS (
                SELECT f3
                FROM t3
                GROUP BY 1
        )
);

drop table t1, t2, t3;

--echo #
--echo # LP BUG#1006231 crash in select_describe
--echo #

create table t1(a1 int) ENGINE=InnoDB;
insert into t1 values (1);
explain
select 1 from t1 where 1 like (select 1 from t1 where 1 <=> (select 1 from t1 group by a1));
select 1 from t1 where 1 like (select 1 from t1 where 1 <=> (select 1 from t1 group by a1));
drop table t1;


--echo #
--echo # MDEV-3988 crash in create_tmp_table
--echo #

drop table if exists `t1`,`t2`;
create table `t1`(`a` char(1) character set utf8)engine=innodb;
create table `t2`(`b` char(1) character set utf8)engine=memory;
select distinct (select 1 from `t2` where `a`) `d2` from `t1`;
select distinct (select 1 from `t2` where `a`) `d2`, a from `t1`;
select distinct a, (select 1 from `t2` where `a`) `d2` from `t1`;
select distinct (1 + (select 1 from `t2` where `a`)) `d2` from `t1`;

drop table t1,t2;

--echo #
--echo # MDEV-4042: Assertion `table->key_read == 0' fails in close_thread_table on EXPLAIN with GROUP BY and HAVING in EXISTS SQ, 
--echo # MDEV-4536: ...sql/sql_base.cc:1598: bool close_thread_table(THD*, TABLE**): Assertion `table->key_read == 0' failed.
CREATE TABLE t1 (a INT) ENGINE=InnoDB;
CREATE TABLE t2 (b INT PRIMARY KEY, c INT) ENGINE=InnoDB;
CREATE TABLE t3 (d INT) ENGINE=InnoDB;

EXPLAIN 
SELECT * FROM t1 WHERE EXISTS ( SELECT b FROM t2, t3 GROUP BY b HAVING b != 3 );
SELECT * FROM t1 WHERE EXISTS ( SELECT b FROM t2, t3 GROUP BY b HAVING b != 3 );

DROP TABLE t1,t2,t3;

CREATE TABLE t1 (
  pk int auto_increment primary key, 
  col_int_key int(11),
  key col_int_key (col_int_key),col_varchar_key varchar(128), 
  key (col_varchar_key)
) engine=innodb;

EXPLAIN 
SELECT 1 FROM t1 AS alias1 
WHERE EXISTS ( SELECT SQ2_alias1 . col_int_key AS SQ2_field1 
               FROM ( t1 AS SQ2_alias1 RIGHT OUTER JOIN 
                      t1 AS SQ2_alias2 ON (SQ2_alias2 . col_int_key = SQ2_alias1 . col_int_key ) 
                    ) 
               GROUP BY SQ2_field1 
               HAVING SQ2_alias1 . col_int_key >= 7
             );

SELECT 1 FROM t1 AS alias1 
WHERE EXISTS ( SELECT SQ2_alias1 . col_int_key AS SQ2_field1 
               FROM ( t1 AS SQ2_alias1 RIGHT OUTER JOIN 
                      t1 AS SQ2_alias2 ON (SQ2_alias2 . col_int_key = SQ2_alias1 . col_int_key ) 
                    ) 
               GROUP BY SQ2_field1 
               HAVING SQ2_alias1 . col_int_key >= 7
             );
drop table t1;


set optimizer_switch=@subselect_innodb_tmp;

--echo #
--echo # MDEV-6041: ORDER BY+subqueries: subquery_table.key=outer_table.col is not recongized as binding
--echo #
create table t1(a int) engine=innodb;
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

create table t2(
  id int primary key,
  key1 int,
  col1 int,
  key(key1)
) engine=innodb;

insert into t2 
  select 
    A.a + B.a*10 + C.a*100 + D.a* 1000, 
    A.a + 10*B.a, 
    123456 
from t1 A, t1 B, t1 C, t1 D;

--echo # Table tsubq:
--echo #   - must use 'ref' (not 'index'), and must not use 'Using filesort'
--echo #   - shows a bad estimate for 'rows' (but I'm not sure if one can do better w/o histograms)
explain select 
   (SELECT 
      concat(id, '-', key1, '-', col1)
    FROM t2
    WHERE t2.key1 = t1.a
    ORDER BY t2.id ASC LIMIT 1)
from 
  t1;

--echo #
--echo # MDEV-6081: ORDER BY+ref(const): selectivity is very incorrect (MySQL Bug#14338686)
--echo #

alter table t2 add key2 int;
update t2 set key2=key1;
alter table t2 add key(key2);
analyze table t2;
flush tables;
--echo # Table tsubq must use 'ref' + Using filesort (not 'index' w/o filesort)
--replace_column 9 #
explain select 
   (SELECT 
      concat(id, '-', key1, '-', col1)
    FROM t2
    WHERE t2.key1 = t1.a
    ORDER BY t2.key2 ASC LIMIT 1)
from 
  t1;

drop table t1,t2;