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
|
drop table if exists t1, t2;
CREATE TABLE t1 (
event_date date DEFAULT '0000-00-00' NOT NULL,
type int(11) DEFAULT '0' NOT NULL,
event_id int(11) DEFAULT '0' NOT NULL,
PRIMARY KEY (event_date,type,event_id)
);
INSERT INTO t1 VALUES ('1999-07-10',100100,24), ('1999-07-11',100100,25),
('1999-07-13',100600,0), ('1999-07-13',100600,4), ('1999-07-13',100600,26),
('1999-07-14',100600,10), ('1999-07-15',100600,16), ('1999-07-15',100800,45),
('1999-07-15',101000,47), ('1999-07-16',100800,46), ('1999-07-20',100600,5),
('1999-07-20',100600,27), ('1999-07-21',100600,11), ('1999-07-22',100600,17),
('1999-07-23',100100,39), ('1999-07-24',100100,39), ('1999-07-24',100500,40),
('1999-07-25',100100,39), ('1999-07-27',100600,1), ('1999-07-27',100600,6),
('1999-07-27',100600,28), ('1999-07-28',100600,12), ('1999-07-29',100500,41),
('1999-07-29',100600,18), ('1999-07-30',100500,41), ('1999-07-31',100500,41),
('1999-08-01',100700,34), ('1999-08-03',100600,7), ('1999-08-03',100600,29),
('1999-08-04',100600,13), ('1999-08-05',100500,42), ('1999-08-05',100600,19),
('1999-08-06',100500,42), ('1999-08-07',100500,42), ('1999-08-08',100500,42),
('1999-08-10',100600,2), ('1999-08-10',100600,9), ('1999-08-10',100600,30),
('1999-08-11',100600,14), ('1999-08-12',100600,20), ('1999-08-17',100500,8),
('1999-08-17',100600,31), ('1999-08-18',100600,15), ('1999-08-19',100600,22),
('1999-08-24',100600,3), ('1999-08-24',100600,32), ('1999-08-27',100500,43),
('1999-08-31',100600,33), ('1999-09-17',100100,37), ('1999-09-18',100100,37),
('1999-09-19',100100,37), ('2000-12-18',100700,38);
select event_date,type,event_id from t1 WHERE event_date >= "1999-07-01" AND event_date < "1999-07-15" AND (type=100600 OR type=100100) ORDER BY event_date;
event_date type event_id
1999-07-10 100100 24
1999-07-11 100100 25
1999-07-13 100600 0
1999-07-13 100600 4
1999-07-13 100600 26
1999-07-14 100600 10
explain select event_date,type,event_id from t1 WHERE type = 100601 and event_date >= "1999-07-01" AND event_date < "1999-07-15" AND (type=100600 OR type=100100) ORDER BY event_date;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
select event_date,type,event_id from t1 WHERE event_date >= "1999-07-01" AND event_date <= "1999-07-15" AND (type=100600 OR type=100100) or event_date >= "1999-07-01" AND event_date <= "1999-07-15" AND type=100099;
event_date type event_id
1999-07-10 100100 24
1999-07-11 100100 25
1999-07-13 100600 0
1999-07-13 100600 4
1999-07-13 100600 26
1999-07-14 100600 10
1999-07-15 100600 16
drop table t1;
CREATE TABLE t1 (
PAPER_ID smallint(6) DEFAULT '0' NOT NULL,
YEAR smallint(6) DEFAULT '0' NOT NULL,
ISSUE smallint(6) DEFAULT '0' NOT NULL,
CLOSED tinyint(4) DEFAULT '0' NOT NULL,
ISS_DATE date DEFAULT '0000-00-00' NOT NULL,
PRIMARY KEY (PAPER_ID,YEAR,ISSUE)
);
INSERT INTO t1 VALUES (3,1999,34,0,'1999-07-12'), (1,1999,111,0,'1999-03-23'),
(1,1999,222,0,'1999-03-23'), (3,1999,33,0,'1999-07-12'),
(3,1999,32,0,'1999-07-12'), (3,1999,31,0,'1999-07-12'),
(3,1999,30,0,'1999-07-12'), (3,1999,29,0,'1999-07-12'),
(3,1999,28,0,'1999-07-12'), (1,1999,40,1,'1999-05-01'),
(1,1999,41,1,'1999-05-01'), (1,1999,42,1,'1999-05-01'),
(1,1999,46,1,'1999-05-01'), (1,1999,47,1,'1999-05-01'),
(1,1999,48,1,'1999-05-01'), (1,1999,49,1,'1999-05-01'),
(1,1999,50,0,'1999-05-01'), (1,1999,51,0,'1999-05-01'),
(1,1999,200,0,'1999-06-28'), (1,1999,52,0,'1999-06-28'),
(1,1999,53,0,'1999-06-28'), (1,1999,54,0,'1999-06-28'),
(1,1999,55,0,'1999-06-28'), (1,1999,56,0,'1999-07-01'),
(1,1999,57,0,'1999-07-01'), (1,1999,58,0,'1999-07-01'),
(1,1999,59,0,'1999-07-01'), (1,1999,60,0,'1999-07-01'),
(3,1999,35,0,'1999-07-12');
select YEAR,ISSUE from t1 where PAPER_ID=3 and (YEAR>1999 or (YEAR=1999 and ISSUE>28)) order by YEAR,ISSUE;
YEAR ISSUE
1999 29
1999 30
1999 31
1999 32
1999 33
1999 34
1999 35
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
repair table t1;
Table Op Msg_type Msg_text
test.t1 repair status OK
drop table t1;
CREATE TABLE t1 (
id int(11) NOT NULL auto_increment,
parent_id int(11) DEFAULT '0' NOT NULL,
level tinyint(4) DEFAULT '0' NOT NULL,
PRIMARY KEY (id),
KEY parent_id (parent_id),
KEY level (level)
);
INSERT INTO t1 VALUES (1,0,0), (3,1,1), (4,1,1), (8,2,2), (9,2,2), (17,3,2),
(22,4,2), (24,4,2), (28,5,2), (29,5,2), (30,5,2), (31,6,2), (32,6,2), (33,6,2),
(203,7,2), (202,7,2), (20,3,2), (157,0,0), (193,5,2), (40,7,2), (2,1,1),
(15,2,2), (6,1,1), (34,6,2), (35,6,2), (16,3,2), (7,1,1), (36,7,2), (18,3,2),
(26,5,2), (27,5,2), (183,4,2), (38,7,2), (25,5,2), (37,7,2), (21,4,2),
(19,3,2), (5,1,1), (179,5,2);
SELECT * FROM t1 WHERE level = 1 AND parent_id = 1;
id parent_id level
3 1 1
4 1 1
2 1 1
6 1 1
7 1 1
5 1 1
SELECT * FROM t1 WHERE level = 1 AND parent_id = 1 order by id;
id parent_id level
2 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
drop table t1;
create table t1(
Satellite varchar(25) not null,
SensorMode varchar(25) not null,
FullImageCornersUpperLeftLongitude double not null,
FullImageCornersUpperRightLongitude double not null,
FullImageCornersUpperRightLatitude double not null,
FullImageCornersLowerRightLatitude double not null,
index two (Satellite, SensorMode, FullImageCornersUpperLeftLongitude, FullImageCornersUpperRightLongitude, FullImageCornersUpperRightLatitude, FullImageCornersLowerRightLatitude));
insert into t1 values("OV-3","PAN1",91,-92,40,50);
insert into t1 values("OV-4","PAN1",91,-92,40,50);
select * from t1 where t1.Satellite = "OV-3" and t1.SensorMode = "PAN1" and t1.FullImageCornersUpperLeftLongitude > -90.000000 and t1.FullImageCornersUpperRightLongitude < -82.000000;
Satellite SensorMode FullImageCornersUpperLeftLongitude FullImageCornersUpperRightLongitude FullImageCornersUpperRightLatitude FullImageCornersLowerRightLatitude
OV-3 PAN1 91 -92 40 50
drop table t1;
create table t1 ( aString char(100) not null default "", key aString (aString(10)) );
insert t1 (aString) values ( "believe in myself" ), ( "believe" ), ("baaa" ), ( "believe in love");
select * from t1 where aString < "believe in myself" order by aString;
aString
baaa
believe
believe in love
select * from t1 where aString > "believe in love" order by aString;
aString
believe in myself
alter table t1 drop key aString;
select * from t1 where aString < "believe in myself" order by aString;
aString
baaa
believe
believe in love
select * from t1 where aString > "believe in love" order by aString;
aString
believe in myself
drop table t1;
CREATE TABLE t1 (
t1ID int(10) unsigned NOT NULL auto_increment,
art char(1) binary NOT NULL default '',
KNR char(5) NOT NULL default '',
RECHNR char(6) NOT NULL default '',
POSNR char(2) NOT NULL default '',
ARTNR char(10) NOT NULL default '',
TEX char(70) NOT NULL default '',
PRIMARY KEY (t1ID),
KEY IdxArt (art),
KEY IdxKnr (KNR),
KEY IdxArtnr (ARTNR)
) TYPE=MyISAM;
INSERT INTO t1 (art) VALUES ('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),('j'),('J'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),
('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j'),('j');
select count(*) from t1 where upper(art) = 'J';
count(*)
213
select count(*) from t1 where art = 'J' or art = 'j';
count(*)
602
select count(*) from t1 where art = 'j' or art = 'J';
count(*)
602
select count(*) from t1 where art = 'j';
count(*)
389
select count(*) from t1 where art = 'J';
count(*)
213
drop table t1;
create table t1 (x int, y int, index(x), index(y));
insert into t1 (x) values (1),(2),(3),(4),(5),(6),(7),(8),(9);
update t1 set y=x;
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 7 and t1.y+0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 range x x 5 NULL 4 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 7 and t2.x <= t1.y+0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 range x x 5 NULL 4 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between t1.y-1 and t1.y+1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Range checked for each record (index map: 0x1)
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= t1.y-1 and t2.x <= t1.y+1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Range checked for each record (index map: 0x1)
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 0 and t1.y;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 0 and t2.x <= t1.y;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 range x x 5 NULL 2 Using where
explain select count(*) from t1 where x in (1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range x x 5 NULL 1 Using where; Using index
explain select count(*) from t1 where x in (1,2);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range x x 5 NULL 2 Using where; Using index
drop table t1;
CREATE TABLE t1 (key1 int(11) NOT NULL default '0', KEY i1 (key1), KEY i2 (key1));
INSERT INTO t1 VALUES (0),(0),(1),(1);
CREATE TABLE t2 (keya int(11) NOT NULL default '0', KEY j1 (keya));
INSERT INTO t2 VALUES (0),(0),(1),(1),(2),(2);
explain select * from t1, t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref j1 j1 4 const 1 Using where; Using index
1 SIMPLE t1 ALL i1,i2 NULL NULL NULL 4 Range checked for each record (index map: 0x3)
explain select * from t1 force index(i2), t2 where (t1.key1 <t2.keya + 1) and t2.keya=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref j1 j1 4 const 1 Using where; Using index
1 SIMPLE t1 ALL i2 NULL NULL NULL 4 Range checked for each record (index map: 0x2)
DROP TABLE t1,t2;
CREATE TABLE t1 (
a int(11) default NULL,
b int(11) default NULL,
KEY a (a),
KEY b (b)
) TYPE=MyISAM;
INSERT INTO t1 VALUES
(1,1),(2,1),(3,1),(4,1),(5,1),(6,1),(7,1),(8,1),(9,1),(10,2),(10,2),
(13,2),(14,2),(15,2),(16,2),(17,3),(17,3),(16,3),(17,3),(19,3),(20,3),
(21,4),(22,5),(23,5),(24,5),(25,5),(26,5),(30,5),(31,5),(32,5),(33,5),
(33,5),(33,5),(33,5),(33,5),(34,5),(35,5);
EXPLAIN SELECT * FROM t1 WHERE a IN(1,2) AND b=5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a,b a 5 NULL 2 Using where
SELECT * FROM t1 WHERE a IN(1,2) AND b=5;
a b
DROP TABLE t1;
create table t1 (id int(10) primary key);
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9);
select id from t1 where id in (2,5,9) ;
id
2
5
9
select id from t1 where id=2 or id=5 or id=9 ;
id
2
5
9
drop table t1;
create table t1 ( id1 int not null, id2 int not null, idnull int null, c char(20), primary key (id1,id2));
insert into t1 values (0,1,NULL,"aaa"), (1,1,NULL,"aaa"), (2,1,NULL,"aaa"),
(3,1,NULL,"aaa"), (4,1,NULL,"aaa"), (5,1,NULL,"aaa"),
(6,1,NULL,"aaa"), (7,1,NULL,"aaa"), (8,1,NULL,"aaa"),
(9,1,NULL,"aaa"), (10,1,NULL,"aaa"), (11,1,NULL,"aaa"),
(12,1,NULL,"aaa"), (13,1,NULL,"aaa"), (14,1,NULL,"aaa"),
(15,1,NULL,"aaa"), (16,1,NULL,"aaa"), (17,1,NULL,"aaa"),
(18,1,NULL,"aaa"), (19,1,NULL,"aaa"), (20,1,NULL,"aaa");
select a.id1, b.idnull from t1 as a, t1 as b where a.id2=1 and a.id1=1 and b.id1=a.idnull order by b.id2 desc limit 1;
id1 idnull
drop table t1;
create table t1 (
id int not null auto_increment,
name char(1) not null,
uid int not null,
primary key (id),
index uid_index (uid));
create table t2 (
id int not null auto_increment,
name char(1) not null,
uid int not null,
primary key (id),
index uid_index (uid));
insert into t1(id, uid, name) values(1, 0, ' ');
insert into t1(uid, name) values(0, ' ');
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
insert into t2(uid, name) select uid, name from t1;
insert into t2(uid, name) select uid, name from t1;
insert into t2(uid, name) select uid, name from t1;
insert into t2(uid, name) select uid, name from t1;
insert into t1(uid, name) select uid, name from t2;
delete from t2;
insert into t2(uid, name) values
(1, CHAR(64+1)),
(2, CHAR(64+2)),
(3, CHAR(64+3)),
(4, CHAR(64+4)),
(5, CHAR(64+5)),
(6, CHAR(64+6)),
(7, CHAR(64+7)),
(8, CHAR(64+8)),
(9, CHAR(64+9)),
(10, CHAR(64+10)),
(11, CHAR(64+11)),
(12, CHAR(64+12)),
(13, CHAR(64+13)),
(14, CHAR(64+14)),
(15, CHAR(64+15)),
(16, CHAR(64+16)),
(17, CHAR(64+17)),
(18, CHAR(64+18)),
(19, CHAR(64+19)),
(20, CHAR(64+20)),
(21, CHAR(64+21)),
(22, CHAR(64+22)),
(23, CHAR(64+23)),
(24, CHAR(64+24)),
(25, CHAR(64+25)),
(26, CHAR(64+26));
insert into t1(uid, name) select uid, name from t2;
delete from t2;
insert into t2(id, uid, name) select id, uid, name from t1;
select count(*) from t1;
count(*)
1026
select count(*) from t2;
count(*)
1026
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 128 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid != 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 129 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
id name uid id name uid
1001 A 1 1001 A 1
1002 B 2 1002 B 2
1003 C 3 1003 C 3
1004 D 4 1004 D 4
1005 E 5 1005 E 5
1006 F 6 1006 F 6
1007 G 7 1007 G 7
1008 H 8 1008 H 8
1009 I 9 1009 I 9
1010 J 10 1010 J 10
1011 K 11 1011 K 11
1012 L 12 1012 L 12
1013 M 13 1013 M 13
1014 N 14 1014 N 14
1015 O 15 1015 O 15
1016 P 16 1016 P 16
1017 Q 17 1017 Q 17
1018 R 18 1018 R 18
1019 S 19 1019 S 19
1020 T 20 1020 T 20
1021 U 21 1021 U 21
1022 V 22 1022 V 22
1023 W 23 1023 W 23
1024 X 24 1024 X 24
1025 Y 25 1025 Y 25
1026 Z 26 1026 Z 26
select * from t1, t2 where t1.uid=t2.uid AND t1.uid != 0;
id name uid id name uid
1001 A 1 1001 A 1
1002 B 2 1002 B 2
1003 C 3 1003 C 3
1004 D 4 1004 D 4
1005 E 5 1005 E 5
1006 F 6 1006 F 6
1007 G 7 1007 G 7
1008 H 8 1008 H 8
1009 I 9 1009 I 9
1010 J 10 1010 J 10
1011 K 11 1011 K 11
1012 L 12 1012 L 12
1013 M 13 1013 M 13
1014 N 14 1014 N 14
1015 O 15 1015 O 15
1016 P 16 1016 P 16
1017 Q 17 1017 Q 17
1018 R 18 1018 R 18
1019 S 19 1019 S 19
1020 T 20 1020 T 20
1021 U 21 1021 U 21
1022 V 22 1022 V 22
1023 W 23 1023 W 23
1024 X 24 1024 X 24
1025 Y 25 1025 Y 25
1026 Z 26 1026 Z 26
drop table t1,t2;
|
