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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019
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CREATE OR REPLACE TABLE t1(a int, b int) engine=aria;
CREATE OR REPLACE TABLE t2(a int, b int) engine=aria;
insert into t1 values (1,10),(2,20),(3,30);
insert into t2 values (2,21),(3,31),(4,41);
#
# Simple selects
#
select a,b,rownum() from t1;
a b rownum()
1 10 1
2 20 2
3 30 3
select a,b,rownum() from t1 where rownum() < 2;
a b rownum()
1 10 1
select a,b from t1 where rownum() <= 2;
a b
1 10
2 20
select a,b from t1 where rownum() > 2;
a b
#
# Subqueries
#
select t1.a,rownum(),t3.a,t3.t2_rownum from t1, (select t2.a,rownum() as t2_rownum from t2 where rownum() <=2) t3;
a rownum() a t2_rownum
1 1 2 1
1 2 3 2
2 3 2 1
2 4 3 2
3 5 2 1
3 6 3 2
select t1.a, (select t2.b from t2 where t1.a=t2.a and rownum() <= 1) 'b' from t1;
a b
1 NULL
2 21
3 31
select t1.a, t3.a from t1, (select * from t2 where rownum() <= 2) t3;
a a
1 2
1 3
2 2
2 3
3 2
3 3
select * from (select tt.*,rownum() as id from (select * from t1) tt) t3 where id>2;
a b id
3 30 3
#
# Joins
#
select t1.a,t1.b,t2.a,t2.b,rownum() from t1,t2 where rownum() <= 4;
a b a b rownum()
1 10 2 21 1
2 20 2 21 2
3 30 2 21 3
1 10 3 31 4
select *,rownum() from t1,t2 where t1.a=t2.a and rownum()<=2;
a b a b rownum()
2 20 2 21 1
3 30 3 31 2
select * from t1 left join t2 on (t2.a=t1.a and rownum()=0);
a b a b
1 10 NULL NULL
2 20 NULL NULL
3 30 NULL NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()>1);
a b a b
1 10 NULL NULL
2 20 NULL NULL
3 30 NULL NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()<1);
a b a b
1 10 NULL NULL
2 20 NULL NULL
3 30 NULL NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()=1);
a b a b
2 20 2 21
1 10 NULL NULL
3 30 NULL NULL
select * from t1 left join t2 on (t2.a=t1.a and rownum()>=1);
a b a b
2 20 2 21
3 30 3 31
1 10 NULL NULL
#
# Union
#
select * from t1 where rownum() <=2 union select * from t2 where rownum()<= 1;
a b
1 10
2 20
2 21
#
# Order by
#
select * from t1 where rownum() <= 2 order by a desc;
a b
2 20
1 10
explain select * from t1 where rownum() <= 2 order by a desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using filesort
select t1.a,t1.b,rownum() from t1 where rownum() <= 2 order by a desc;
a b rownum()
2 20 2
1 10 1
explain select t1.a,t1.b,rownum() from t1 where rownum() <= 2 order by a desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where; Using temporary; Using filesort
select *,rownum() from t1,t2;
a b a b rownum()
1 10 2 21 1
2 20 2 21 2
3 30 2 21 3
1 10 3 31 4
2 20 3 31 5
3 30 3 31 6
1 10 4 41 7
2 20 4 41 8
3 30 4 41 9
select *,rownum() from t1,t2 order by t2.a desc, t1.a desc;
a b a b rownum()
3 30 4 41 9
2 20 4 41 8
1 10 4 41 7
3 30 3 31 6
2 20 3 31 5
1 10 3 31 4
3 30 2 21 3
2 20 2 21 2
1 10 2 21 1
select * from (select * from t1 order by a desc) as t where rownum() <= 2;
a b
3 30
2 20
select * from t1,t2 where t1.a=t2.a and rownum()<=2 order by t1.a,t2.a;
a b a b
2 20 2 21
3 30 3 31
create view v1 as
select * from (select * from t1 order by a desc) as t where rownum() <= 2;
select * from v1;
a b
3 30
2 20
drop view v1;
#
# Having
#
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2;
a sum(t1.b) r
1 10 1
2 20 2
select * from t1 having rownum() <= 2;
a b
1 10
2 20
select t1.a, sum(t1.b), rownum() from t1 group by t1.a;
a sum(t1.b) rownum()
1 10 1
2 20 2
3 30 3
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2;
a sum(t1.b) r
1 10 1
2 20 2
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having rownum() <= 2;
a sum(t1.b) r
1 10 1
2 20 2
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having r <= 2 order by a desc;
a sum(t1.b) r
2 20 2
1 10 1
select t1.a, sum(t1.b), rownum() as 'r' from t1 group by t1.a having rownum() <= 2 order by a desc;
a sum(t1.b) r
2 20 2
1 10 1
#
# Sum functions
#
select max(rownum()),min(rownum()) from t1;
max(rownum()) min(rownum())
3 1
select sum(rownum()),avg(rownum()) from t1;
sum(rownum()) avg(rownum())
6 2.0000
#
# Group by
#
select t1.a,sum(t1.b) from t1 where rownum() < 2 group by t1.a;
a sum(t1.b)
1 10
select t1.a,sum(t2.b) from t1 JOIN t2 ON (t1.a=t2.a) where rownum() <= 2 group by t1.a;
a sum(t2.b)
2 21
3 31
select * from (select t1.a,sum(t2.b) from t1 JOIN t2 ON (t1.a=t2.a) group by t1.a) as t where rownum() <= 1;
a sum(t2.b)
2 21
select t1.a,sum(rownum()),count(*) from t1 where rownum() <= 2 group by t1.a;
a sum(rownum()) count(*)
1 1 1
2 2 1
select * from (select t1.a,sum(t1.b) from t1 group by t1.a) as t3 where rownum() < 2;
a sum(t1.b)
1 10
create table t3 (a int) engine=myisam;
insert into t3 values (3),(5),(5),(3);
select a, max(rownum()) from t3 group by a;
a max(rownum())
3 4
5 3
drop table t3;
CREATE TABLE t3 (
a int(11) DEFAULT NULL,
b varchar(1024) DEFAULT NULL
);
insert into t3 select mod(seq*3,20)+1, repeat(char(33+mod(seq,90)),mod(seq,10)*100) from seq_1_to_23;
SELECT sq.a,length(sq.f) FROM (SELECT a, GROUP_CONCAT(b,b) AS f FROM t3 GROUP BY a ORDER BY a desc) as sq WHERE ROWNUM() <= 10;
a length(sq.f)
20 600
19 1200
18 1800
17 400
16 1000
15 1600
14 200
13 800
12 1400
11 0
drop table t3;
#
# Prepared statements
#
PREPARE stmt1 from "select a,b,rownum() from t1 where rownum() <= 2";
execute stmt1;
a b rownum()
1 10 1
2 20 2
execute stmt1;
a b rownum()
1 10 1
2 20 2
deallocate prepare stmt1;
#
# Views
#
create view v1 as select t1.a,rownum() from t1;
select * from v1;
a rownum()
1 1
2 2
3 3
select t1.a,v1.* from t1,v1 where t1.a=v1.a;
a a rownum()
1 1 1
2 2 2
3 3 3
drop view v1;
CREATE TABLE t3 (a INT);
INSERT INTO t3 VALUES (1),(2),(3);
CREATE VIEW v1 AS SELECT a FROM t3 WHERE ROWNUM() <= 2;
SELECT * FROM v1;
a
1
2
drop view v1;
drop table t3;
#
# Reserved words
#
create table t4 (a int, rownum int);
insert into t4 (a,rownum) values (1,2);
select t4.a,t4.rownum from t4;
a rownum
1 2
drop table t4;
#
# Test Oracle mode
#
set SQL_MODE=ORACLE;
select t1.a,rownum from t1 where rownum<=2;
a rownum
1 1
2 2
select t1.a,rownum() from t1 where rownum()<=2;
a rownum()
1 1
2 2
create table t4 (a int, rownum int);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'rownum int)' at line 1
DECLARE
CURSOR c_cursor
IS select a,b,rownum from t1 where rownum <= 2;
v_a t1.a%TYPE;
v_b t1.b%TYPE;
v_rn t1.a%TYPE;
BEGIN
OPEN c_cursor;
FETCH c_cursor INTO v_a, v_b, v_rn;
WHILE c_cursor%FOUND LOOP
SELECT concat(v_a,'--',v_b,'--',v_rn);
FETCH c_cursor INTO v_a, v_b, v_rn;
END LOOP;
CLOSE c_cursor;
END;|
concat(v_a,'--',v_b,'--',v_rn)
1--10--1
concat(v_a,'--',v_b,'--',v_rn)
2--20--2
select a, rownum from t1 group by a, rownum having rownum < 3;
a rownum
1 1
2 2
select a, rownum as r from t1 group by a, rownum having r < 3;
a r
1 1
2 2
select a, rownum from t1 group by a, rownum having "rownum" < 3;
a rownum
1 1
2 2
select a, rownum from t1 group by a, rownum having rownum < 3 order by a desc;
a rownum
2 2
1 1
select a, rownum as r from t1 group by a, rownum having r < 3 order by a desc;
a r
2 2
1 1
select a, rownum from t1 group by a, rownum having "rownum" < 3 order by a desc;
a rownum
2 2
1 1
set SQL_MODE=DEFAULT;
# Cleanup
drop table t1,t2;
#
# INSERT
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,rownum()),(2,rownum()),(3,rownum());
select * from t1;
a b
1 1
2 2
3 3
drop table t1;
#
# INSERT DELAYED
#
create table t1 (a int not null primary key, b int);
insert delayed into t1 values (1,rownum()),(2,rownum()),(3,rownum());
select * from t1;
a b
1 1
2 2
3 3
drop table t1;
#
# INSERT IGNORED
#
create table t1 (a int not null primary key, b int);
insert ignore into t1 values (1,rownum()),(2,rownum()),(2,rownum()),(3,rownum());
Warnings:
Warning 1062 Duplicate entry '2' for key 'PRIMARY'
select * from t1;
a b
1 1
2 2
3 4
delete from t1;
insert ignore into t1 select * from (values (1,rownum()),(2,rownum()),(2,rownum()),(3,rownum())) t;
Warnings:
Warning 1062 Duplicate entry '2' for key 'PRIMARY'
select * from t1;
a b
1 1
2 2
3 4
drop table t1;
#
# INSERT ... RETURNING
#
create or replace table t1 (a int);
insert into t1 values (1),(2) returning a, rownum();
a rownum()
1 1
2 2
drop table t1;
#
# UPDATE
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,2),(3,3);
update t1 set b=0;
update t1 set b=rownum()+1;
select * from t1;
a b
1 2
2 3
3 4
update t1 set b=0;
update t1 set b=rownum() where a < 10 and rownum() < 2;
select * from t1;
a b
1 1
2 0
3 0
drop table t1;
create table t1 (a int);
insert into t1 values (10),(20),(30);
update t1 set a = rownum();
select * from t1;
a
1
2
3
update t1 set a = rownum();
select * from t1;
a
1
2
3
drop table t1;
#
# DELETE
#
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,0),(3,0);
delete from t1 where a < 10 and rownum() < 2;
select * from t1;
a b
2 0
3 0
drop table t1;
#
# MULTI-TABLE-DELETE
#
create table t1 (a int not null primary key);
insert into t1 values (1),(2),(3);
create table t2 (a int not null primary key);
insert into t2 values (1),(2),(3);
delete t1,t2 from t1,t2 where t1.a=t2.a and rownum() <= 2;
select * from t1;
a
3
select * from t2;
a
3
drop table t1,t2;
#
# MULTI-TABLE-UPDATE
CREATE TABLE t1 (ID INT);
CREATE TABLE t2 (ID INT,
s1 TEXT, s2 TEXT, s3 VARCHAR(10), s4 TEXT, s5 VARCHAR(10));
INSERT INTO t1 VALUES (1),(2);
INSERT INTO t2 VALUES (1,'test', 'test', 'test', 'test', 'test'),
(2,'test', 'test', 'test', 'test', 'test');
SELECT * FROM t1 LEFT JOIN t2 USING(ID);
ID s1 s2 s3 s4 s5
1 test test test test test
2 test test test test test
UPDATE t1 LEFT JOIN t2 USING(ID) SET s1 = 'changed';
select * from t2;
ID s1 s2 s3 s4 s5
1 changed test test test test
2 changed test test test test
update t2 set s1="";
UPDATE t1 LEFT JOIN t2 USING(ID) SET s1 = 'changed' where rownum() <=1;
select * from t2;
ID s1 s2 s3 s4 s5
1 changed test test test test
2 test test test test
drop table t1,t2;
#
# LOAD DATA
#
create table t1 (a int, b int, c int);
load data infile '../../std_data/loaddata7.dat' into table t1 fields terminated by ',' lines terminated by "\r\n" (a,b) set c=rownum();
select * from t1;
a b c
2 2 1
3 3 2
4 4 3
5 5 4
6 6 5
drop table t1;
#
# LIMIT OPTIMIZATION
#
create table t1 (a int);
insert into t1 select seq from seq_1_to_100;
flush status;
select * from t1 where rownum() <= 3;
a
1
2
3
show status like "Rows_read";
Variable_name Value
Rows_read 3
flush status;
select * from t1 where rownum() <= 4 and rownum() <= 3;
a
1
2
3
show status like "Rows_read";
Variable_name Value
Rows_read 3
flush status;
select * from t1 where rownum() < 4 and a > 10;
a
11
12
13
show status like "Rows_read";
Variable_name Value
Rows_read 13
flush status;
select * from t1 where 3 >= rownum();
a
1
2
3
show status like "Rows_read";
Variable_name Value
Rows_read 3
flush status;
select * from t1 where 4 > rownum() and a > 20;
a
21
22
23
show status like "Rows_read";
Variable_name Value
Rows_read 23
flush status;
select * from t1 where rownum() = 1 and a > 10;
a
11
show status like "Rows_read";
Variable_name Value
Rows_read 11
flush status;
select * from t1 where a > 30 && 1 = rownum();
a
31
show status like "Rows_read";
Variable_name Value
Rows_read 31
flush status;
# No limit optimization
select * from t1 where rownum() > 10;
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where 10 < rownum();
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where rownum() >= 10;
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where 10 < rownum();
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where 10 <= rownum();
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where 2 = rownum();
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where rownum() = 2;
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select * from t1 where rownum() <= 0;
a
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
select *,rownum() from t1 where rownum() < 10 limit 4, 4;
a rownum()
5 5
6 6
7 7
8 8
show status like "Rows_read";
Variable_name Value
Rows_read 8
flush status;
select * from t1 where rownum() < 10 order by a;
a
1
2
3
4
5
6
7
8
9
show status like "Rows_read";
Variable_name Value
Rows_read 100
flush status;
# rownum and limit
select * from t1 where rownum() < 4 limit 10;
a
1
2
3
show status like "Rows_read";
Variable_name Value
Rows_read 3
flush status;
select * from t1 where rownum() < 10 limit 4;
a
1
2
3
4
show status like "Rows_read";
Variable_name Value
Rows_read 4
drop table t1;
#
# Rownum examples from Woqutech
#
set SQL_MODE=ORACLE;
create table t1 (c1 int ,c2 varchar(20)) engine=myisam;
insert into t1 values (1, 'aaa'),(2, 'bbb'),(3, 'ccc'),(4, 'ddd'),(5, 'eee');
update t1 set c2 = 'xxx' where rownum = 2;
select * from t1 where c2='xxx';
c1 c2
update t1 set c2 = 'xxx' where rownum < 3;
select * from t1 where c2='xxx';
c1 c2
1 xxx
2 xxx
delete from t1 where rownum = 2;
select count(*) from t1;
count(*)
5
delete from t1 where rownum < 3;
select count(*) from t1;
count(*)
3
delete from t1 where c1=rownum ;
select count(*) from t1;
count(*)
3
delete from t1 where c1=rownum+2 ;
select count(*) from t1;
count(*)
0
set SQL_MODE=DEFAULT;
drop table t1;
#
# Rownum() used in not supported places (returns 0 or gives an error)
#
set @a=rownum();
select @a;
@a
0
create or replace table t (a int, b int as (rownum()) virtual);
ERROR HY000: Function or expression 'rownum()' cannot be used in the GENERATED ALWAYS AS clause of `b`
create table t1 (a int);
insert into t1 values (3),(1),(5),(8),(4);
handler t1 open;
handler t1 read next where rownum() < 1;
ERROR HY000: Function or expression 'rownum()' cannot be used in the WHERE clause of `HANDLER`
handler t1 close;
drop table t1;
create table t1 (a int not null primary key, b int);
insert into t1 values (1,1),(2,2),(3,3);
create function f() returns int return rownum();
select a, rownum(), f() from t1;
a rownum() f()
1 1 0
2 2 0
3 3 0
drop function f;
drop table t1;
create or replace table t1 (a int, r int);
create trigger tr before update on t1 for each row set NEW.r = rownum();
insert into t1 (a) values (1),(2);
select * from t1;
a r
1 NULL
2 NULL
update t1 set a=a+10;
select * from t1;
a r
11 0
12 0
drop trigger tr;
drop table t1;
#
# LIMIT optimisation
#
create table t1 (a int);
insert into t1 values (1),(2),(3),(4),(5);
flush status;
select * from (select a from t1 where a < 1000) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 2
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() <= 2";
flush status;
execute stmt;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 2
flush status;
execute stmt;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 5
explain extended select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where; Using temporary; Using filesort
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 5
explain extended select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where; Using temporary; Using filesort
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
flush status;
select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2;
a
1
2
show status like "Rows_read";
Variable_name Value
Rows_read 5
explain extended select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
3 UNION NULL NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL NULL
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 union /* select#3 */ select 10 AS `10` limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 union select 10) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# Other limit
select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2;
a
1
explain extended select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where; Using temporary; Using filesort
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 1) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1 limit 1) as tt where rownum() <= 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# Other limit less
select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2;
a
1
2
explain extended select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where; Using temporary; Using filesort
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 group by `test`.`t1`.`a` order by 1 limit 2) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 group by a order by 1 limit 10) as tt where rownum() <= 2";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2;
a
1
explain extended select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 5 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
3 UNION NULL NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL NULL
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 union /* select#3 */ select 10 AS `10` limit 1) `tt` where rownum() <= 2 limit 2
prepare stmt from "select * from (select a from t1 where a < 1000 union select 10 limit 1) as tt where rownum() <= 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# < rownum
select * from (select a from t1 where a < 1000) as tt where rownum() < 2;
a
1
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() < 2;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 1) `tt` where rownum() < 2 limit 1
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() < 2";
execute stmt;
a
1
execute stmt;
a
1
deallocate prepare stmt;
# Simple expression
select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1;
a
1
2
explain extended select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where rownum() <= <cache>(1 + 1) limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where rownum() <= 1+1";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# Simple expression reversed
select * from (select a from t1 where a < 1000) as tt where 1+1 >= rownum();
a
1
2
explain extended select * from (select a from t1 where a < 1000) as tt where 1+1 >= rownum();
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 2) `tt` where <cache>(1 + 1) >= rownum() limit 2
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where 1+1 >= rownum()";
execute stmt;
a
1
2
execute stmt;
a
1
2
deallocate prepare stmt;
# expensive (no opt)
select * from (select a from t1 where a < 1000) as tt where (select max(a) from t1) >= rownum();
a
1
2
3
4
5
explain extended select * from (select a from t1 where a < 1000) as tt where (select max(a) from t1) >= rownum();
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 5 100.00 Using where
3 SUBQUERY t1 ALL NULL NULL NULL NULL 5 100.00
2 DERIVED t1 ALL NULL NULL NULL NULL 5 100.00 Using where
Warnings:
Note 1003 /* select#1 */ select `tt`.`a` AS `a` from (/* select#2 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where `test`.`t1`.`a` < 1000 limit 5) `tt` where (/* select#3 */ select max(`test`.`t1`.`a`) from `test`.`t1`) >= rownum() limit 5
prepare stmt from "select * from (select a from t1 where a < 1000) as tt where (select max(a) from t1) >= rownum()";
execute stmt;
a
1
2
3
4
5
execute stmt;
a
1
2
3
4
5
deallocate prepare stmt;
drop table t1;
#
# Table value constructors
#
values ("first row"),("next row is 3"),(rownum()),("next row is 5"),(rownum());
first row
first row
next row is 3
3
next row is 5
5
#
# MDEV-31073: Server crash, assertion `table != 0 &&
# view->field_translation != 0' failure with ROWNUM and view
#
CREATE TABLE t (f INT);
INSERT INTO t VALUES (1),(2);
CREATE VIEW v AS SELECT * FROM t;
UPDATE v SET f = 10 WHERE ROWNUM() > 42 LIMIT 1;
DROP VIEW v;
DROP TABLE t;
CREATE TABLE t (f INT);
INSERT INTO t VALUES (1),(2);
CREATE VIEW v AS SELECT f, 3 as e FROM t;
UPDATE v SET f = 10 WHERE e > 42 LIMIT 1;
DROP VIEW v;
DROP TABLE t;
CREATE TABLE t (f INT);
INSERT INTO t VALUES (1),(2);
CREATE VIEW v AS SELECT f, ROWNUM() as e FROM t;
UPDATE v SET f = 10 WHERE e > 42 LIMIT 1;
ERROR HY000: The target table v of the UPDATE is not updatable
DROP VIEW v;
DROP TABLE t;
#
# End of 10.6 tests
#
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