Après avoir examiné les autres réponses, cela m'a aidé à réaliser un problème sous-jacent.
La table articles et la table article_images doivent toutes deux avoir un index supplémentaire.
Voici ce que vous avez maintenant :
CREATE TABLE `articles` (
`id` int(10) unsigned not null auto_increment,
`author_id` int(10) unsigned not null,
`date_created` datetime not null,
PRIMARY KEY(id)
) ENGINE=InnoDB;
CREATE TABLE `article_images` (
`article_id` int(10) unsigned not null,
`filename` varchar(100) not null,
`date_added` datetime not null,
UNIQUE INDEX(article_id, filename)
) ENGINE=InnoDB;
Voici ce dont vous avez besoin :
CREATE TABLE `articles` (
`id` int(10) unsigned not null auto_increment,
`author_id` int(10) unsigned not null,
`date_created` datetime not null,
PRIMARY KEY(id),
INDEX (date_created DESC)
) ENGINE=InnoDB;
CREATE TABLE `article_images` (
`article_id` int(10) unsigned not null,
`filename` varchar(100) not null,
`date_added` datetime not null,
UNIQUE INDEX (article_id, filename),
INDEX (article_id, date_added),
) ENGINE=InnoDB;
articles
Le nouvel index pour classer les articles par date d'insertion dans l'ordre décroissant
article_images
Le premier index est toujours nécessaire car il empêchera de joindre une autre image avec le même nom de fichier à un article.
Le deuxième index facilitera la recherche de l'image la plus récente,
Avec ces nouveaux index en place, voici la requête qui répondra à vos attentes :
SELECT
AAA.author_id,
AAA.date_created,
IFNULL(BBB.title,'<NO_TITLE>') title,
IFNULL(CCC.filename,'<NO-IMAGE>') filename
FROM
(
SELECT
AA.id,
AA.date_added,
BB.author_id,
BB.date_created
FROM
(
SELECT
A.id,IFNULL(MAX(B.date_added),'1900-01-01 00:00:00') date_added
FROM (SELECT id FROM articles ORDER BY date_created DESC LIMIT 40) A
LEFT JOIN article_images B ON A.id = B.article_id
GROUP BY A.id
) AA
INNER JOIN articles BB USING (id)
) AAA
LEFT JOIN article_contents BBB ON AAA.id=BBB.article_id
LEFT JOIN article_images CCC
ON (AAA.id=CCC.article_id AND AAA.date_added=CCC.date_added)
ORDER BY AAA.date_created DESC;
L'objectif est d'abord de créer une sous-requête interne qui ne comporte que 40 lignes. C'est ce que les AA devraient ramener. La sous-requête AAA doit contenir les informations sur l'article ainsi que la date à laquelle la dernière image a été insérée. Le dernier ensemble de jointures doit connecter les 40 identifiants avec un titre et une image. La dernière étape consiste à présenter le jeu de résultats par ordre décroissant.
Comme je n'ai pas de données d'exemple, j'ai écrit trois procédures stockées dans une base de données d'exemple appelée stuff
1 pour faire les tableaux
DELIMITER $$
DROP PROCEDURE IF EXISTS `stuff`.`MakeTables` $$
CREATE PROCEDURE `stuff`.`MakeTables` ()
BEGIN
DROP TABLE IF EXISTS articles;
DROP TABLE IF EXISTS article_contents;
DROP TABLE IF EXISTS article_images;
CREATE TABLE `articles` (
`id` int(10) unsigned not null auto_increment,
`author_id` int(10) unsigned not null,
`date_created` datetime not null,
PRIMARY KEY(id),
INDEX (date_created DESC)
) ENGINE=InnoDB;
CREATE TABLE `article_contents` (
`article_id` int(10) unsigned not null,
`title` varchar(100) not null,
`content` text not null,
PRIMARY KEY(article_id)) ENGINE=InnoDB;
CREATE TABLE `article_images` (
`article_id` int(10) unsigned not null,
`filename` varchar(100) not null,
`date_added` datetime not null,
UNIQUE INDEX (article_id, filename),
INDEX (article_id, date_added)
) ENGINE=InnoDB;
END $$
DELIMITER ;
1 pour rendre les données
DELIMITER $$
DROP PROCEDURE IF EXISTS `stuff`.`LoadSampleData` $$
CREATE PROCEDURE `stuff`.`LoadSampleData` ()
BEGIN
DECLARE x,y,z INT;
SET x = 1;
WHILE x <= 100 DO
INSERT INTO articles (author_id,date_created) VALUES
(RAND() * POWER(2,31),
DATE('1970-01-01 00:00:00') + INTERVAL (RAND() * POWER(2,30)) SECOND);
SET x = x + 1;
END WHILE;
SET x = 1;
WHILE x <= 100 DO
SET y = FLOOR(RAND() * 100);
IF y >= 30 THEN
INSERT INTO article_contents
VALUES (x,
CONCAT('TITLE_',FLOOR(RAND() * POWER(2,31))),
CONCAT('CONTENT_',FLOOR(RAND() * POWER(2,31))));
END IF;
SET x = x + 1;
END WHILE;
SET x = 1;
WHILE x <= 100 DO
SELECT COUNT(1) INTO y FROM article_contents WHERE article_id = x;
IF y = 1 THEN
SET y = 0;
WHILE y < 20 DO
SET y = y + 1;
SET z = FLOOR(RAND() * 10);
IF z >= 5 THEN
INSERT INTO article_images
VALUES (x,
CONCAT('IMAGE_',FLOOR(RAND() * POWER(2,31))),
DATE('1970-01-01 00:00:00') + INTERVAL (RAND() * POWER(2,30)) SECOND);
END IF;
END WHILE;
END IF;
SET x = x + 1;
END WHILE;
SELECT COUNT(1) INTO x FROM articles;
SELECT COUNT(1) INTO y FROM article_contents;
SELECT COUNT(1) INTO z FROM article_images;
SELECT CONCAT('Articles:',x,' Titles:',y,' Images: ',z) Results;
END $$
DELIMITER ;
1 pour exécuter la requête
DELIMITER $$
DROP PROCEDURE IF EXISTS `stuff`.`ShowLast40` $$
CREATE PROCEDURE `stuff`.`ShowLast40` ()
BEGIN
SELECT
AAA.author_id,
AAA.date_created,
IFNULL(BBB.title,'<NO_TITLE>') title,
IFNULL(CCC.filename,'<NO-IMAGE>') filename
FROM
(
SELECT
AA.id,
AA.date_added,
BB.author_id,
BB.date_created
FROM
(
SELECT
A.id,IFNULL(MAX(B.date_added),'1900-01-01 00:00:00') date_added
FROM (SELECT id FROM articles ORDER BY date_created DESC LIMIT 40) A
LEFT JOIN article_images B ON A.id = B.article_id
GROUP BY A.id
) AA
INNER JOIN articles BB USING (id)
) AAA
LEFT JOIN article_contents BBB ON AAA.id=BBB.article_id
LEFT JOIN article_images CCC
ON (AAA.id=CCC.article_id AND AAA.date_added=CCC.date_added)
ORDER BY AAA.date_created DESC;
END $$
DELIMITER ;
Voici un exemple de sortie lorsque je l'ai exécuté sur mon bureau Windows (MySQL 5.5.12) :
mysql> call maketables; call loadsampledata;
Query OK, 0 rows affected (0.31 sec)
+------------------------------------+
| Results |
+------------------------------------+
| Articles:100 Titles:67 Images: 666 |
+------------------------------------+
1 row in set (23.73 sec)
mysql> call showlast40;
+------------+---------------------+------------------+------------------+
| author_id | date_created | title | filename |
+------------+---------------------+------------------+------------------+
| 1576679519 | 2004-01-02 14:05:17 | TITLE_1757853515 | IMAGE_1601858163 |
| 992840519 | 2003-05-17 05:48:11 | TITLE_319026350 | IMAGE_1913708631 |
| 1366977197 | 2003-03-20 19:37:23 | <NO_TITLE> | <NO-IMAGE> |
| 1705517382 | 2003-02-07 16:48:56 | <NO_TITLE> | <NO-IMAGE> |
| 1529899841 | 2002-11-02 20:59:26 | <NO_TITLE> | <NO-IMAGE> |
| 1756824942 | 2002-08-28 16:01:59 | <NO_TITLE> | <NO-IMAGE> |
| 175825630 | 2002-05-08 13:48:56 | TITLE_240812804 | IMAGE_1214850809 |
| 757530551 | 2002-02-08 00:20:17 | TITLE_4447486 | IMAGE_1511850161 |
| 840251261 | 2002-01-25 20:06:56 | TITLE_1160842143 | IMAGE_206027488 |
| 964653347 | 2001-12-26 19:15:47 | TITLE_1552408257 | IMAGE_717719932 |
| 2106039126 | 2001-11-11 17:09:29 | <NO_TITLE> | <NO-IMAGE> |
| 2085991608 | 2001-08-01 12:48:20 | <NO_TITLE> | <NO-IMAGE> |
| 1895462094 | 2000-12-02 05:31:41 | <NO_TITLE> | <NO-IMAGE> |
| 1589384729 | 2000-04-28 23:55:50 | TITLE_1040850308 | IMAGE_1200414639 |
| 514341550 | 2000-04-20 07:25:05 | TITLE_188288840 | IMAGE_164856430 |
| 887359583 | 2000-02-13 03:30:47 | <NO_TITLE> | <NO-IMAGE> |
| 1156687499 | 1999-06-16 00:29:17 | TITLE_686398996 | IMAGE_670200418 |
| 1561242593 | 1998-12-08 05:50:17 | <NO_TITLE> | <NO-IMAGE> |
| 1117889993 | 1998-10-23 17:02:44 | TITLE_1491217221 | IMAGE_649630126 |
| 740063135 | 1998-09-16 23:52:41 | TITLE_579374776 | IMAGE_757313192 |
| 429699232 | 1998-04-19 01:41:17 | TITLE_73748980 | IMAGE_1881818111 |
| 1827051060 | 1998-02-27 01:01:50 | TITLE_1588619991 | IMAGE_1657322715 |
| 1442984429 | 1997-11-19 21:23:35 | TITLE_184173382 | IMAGE_597809368 |
| 152267158 | 1997-05-02 20:25:50 | <NO_TITLE> | <NO-IMAGE> |
| 1323598169 | 1997-03-14 16:30:38 | TITLE_1355869397 | IMAGE_1058313818 |
| 66122740 | 1997-01-05 15:12:20 | TITLE_1259073183 | IMAGE_198280936 |
| 5161474 | 1996-06-28 10:47:26 | TITLE_1876022823 | IMAGE_1138098675 |
| 1865082792 | 1996-03-01 19:09:11 | TITLE_1288151615 | IMAGE_245974646 |
| 1923481146 | 1995-08-07 00:36:11 | TITLE_922744000 | IMAGE_2067090321 |
| 1725218958 | 1995-03-18 05:15:29 | TITLE_583120586 | IMAGE_592773824 |
| 117806248 | 1995-01-05 02:34:32 | <NO_TITLE> | <NO-IMAGE> |
| 1428777335 | 1993-06-06 01:52:32 | TITLE_661148588 | IMAGE_633345518 |
| 1091245943 | 1993-06-05 05:51:47 | TITLE_1407444563 | IMAGE_538936256 |
| 2088382260 | 1993-03-25 06:03:29 | TITLE_1144364681 | IMAGE_1790013089 |
| 625878569 | 1992-12-21 07:41:26 | TITLE_1319355723 | IMAGE_921580624 |
| 110555110 | 1992-01-01 20:49:59 | <NO_TITLE> | <NO-IMAGE> |
| 1110532475 | 1991-11-20 07:19:32 | <NO_TITLE> | <NO-IMAGE> |
| 1726795146 | 1990-10-09 00:23:44 | TITLE_782624350 | IMAGE_1760322575 |
| 370183888 | 1990-03-30 15:59:17 | <NO_TITLE> | <NO-IMAGE> |
| 1497483317 | 1990-02-19 01:25:41 | TITLE_776483948 | IMAGE_665824222 |
+------------+---------------------+------------------+------------------+
40 rows in set (0.00 sec)
Essayez-le !!!
MISE À JOUR
Je me suis assuré que les 40 dates-heures que vous lisez sont en fait les 40 meilleures. Elles le sont. J'ai lancé la requête :select * from articles ORDER BY date_created DESC; pour s'en assurer.
MISE À JOUR 2011-05-17 14:06
mysql> call maketables; call loadsampledata;
Query OK, 0 rows affected (0.45 sec)
+-------------------------------------+
| Results |
+-------------------------------------+
| Articles:100 Titles:67 Images: 6739 |
+-------------------------------------+
1 row in set (3 min 45.45 sec)
Query OK, 0 rows affected (3 min 45.45 sec)
mysql> call showlast40;
+------------+---------------------+------------------+------------------+
| author_id | date_created | title | filename |
+------------+---------------------+------------------+------------------+
| 196582776 | 2004-01-05 14:09:04 | <NO_TITLE> | <NO-IMAGE> |
| 1880371016 | 2003-07-31 05:50:37 | TITLE_1191518827 | IMAGE_1562208019 |
| 22204986 | 2003-02-16 14:09:22 | <NO_TITLE> | <NO-IMAGE> |
| 355490160 | 2002-11-21 02:35:19 | <NO_TITLE> | <NO-IMAGE> |
| 869510149 | 2001-12-27 22:07:52 | TITLE_1528616779 | IMAGE_223327284 |
| 2063556512 | 2001-04-16 18:47:46 | TITLE_1839975091 | IMAGE_1282187005 |
| 529754190 | 2000-07-14 19:44:01 | TITLE_1557423205 | IMAGE_1931606737 |
| 166226262 | 1999-11-08 03:27:22 | <NO_TITLE> | <NO-IMAGE> |
| 1981417562 | 1999-09-11 12:59:10 | TITLE_198262896 | IMAGE_1491273871 |
| 831057001 | 1999-06-14 15:06:31 | TITLE_1170272131 | IMAGE_760396200 |
| 1454252623 | 1998-06-02 08:35:46 | <NO_TITLE> | <NO-IMAGE> |
| 1435450777 | 1997-11-17 18:10:34 | TITLE_482497458 | IMAGE_1331932705 |
| 1536315541 | 1997-11-02 05:24:49 | <NO_TITLE> | <NO-IMAGE> |
| 2078028530 | 1997-03-14 22:36:58 | TITLE_321332010 | IMAGE_1897983295 |
| 701651581 | 1997-01-13 22:36:58 | TITLE_1337390701 | IMAGE_1630983859 |
| 101442444 | 1996-11-22 09:40:16 | <NO_TITLE> | <NO-IMAGE> |
| 51114930 | 1996-11-20 03:24:49 | TITLE_1866751135 | IMAGE_1669595407 |
| 722056183 | 1996-08-03 15:23:01 | <NO_TITLE> | <NO-IMAGE> |
| 1178720989 | 1996-06-29 22:47:19 | TITLE_579734376 | IMAGE_833229222 |
| 511355958 | 1996-03-10 09:32:46 | TITLE_1540275289 | IMAGE_1168117261 |
| 831921829 | 1996-01-31 06:36:04 | TITLE_661038882 | IMAGE_1199197195 |
| 1288455163 | 1995-08-22 00:34:25 | TITLE_1599332515 | IMAGE_822445764 |
| 1976208956 | 1995-06-02 09:23:01 | TITLE_58372998 | IMAGE_793318650 |
| 2092066982 | 1995-03-28 20:35:37 | TITLE_1693142377 | IMAGE_1176935479 |
| 1083841549 | 1994-07-11 18:46:52 | TITLE_1955674591 | IMAGE_1240485919 |
| 359037132 | 1994-07-11 02:44:19 | TITLE_713454936 | IMAGE_1072569732 |
| 1471985773 | 1994-05-10 17:08:01 | TITLE_1065017724 | IMAGE_393097704 |
| 1888864730 | 1994-01-15 17:41:28 | TITLE_1060275498 | IMAGE_230810100 |
| 1688028488 | 1993-12-28 06:36:58 | <NO_TITLE> | <NO-IMAGE> |
| 1739777948 | 1993-02-15 00:30:31 | TITLE_1226842225 | IMAGE_1615058467 |
| 445721334 | 1991-12-15 20:54:49 | TITLE_1336145587 | IMAGE_2114729323 |
| 1661002442 | 1991-06-30 05:49:34 | TITLE_151142910 | IMAGE_1623325381 |
| 2092223006 | 1991-06-13 13:15:58 | TITLE_33175860 | IMAGE_1225117771 |
| 1553434585 | 1991-01-12 03:34:25 | TITLE_728483442 | IMAGE_1954153339 |
| 528544608 | 1990-11-10 08:21:04 | <NO_TITLE> | <NO-IMAGE> |
| 1043927395 | 1990-10-05 00:48:49 | TITLE_304307448 | IMAGE_1702062493 |
| 1685702960 | 1990-04-28 05:44:19 | TITLE_1909853341 | IMAGE_263553036 |
| 1392428383 | 1990-03-07 15:08:46 | <NO_TITLE> | <NO-IMAGE> |
| 643714153 | 1990-02-14 08:32:10 | TITLE_837416724 | IMAGE_1673964259 |
| 2132028206 | 1989-09-28 16:04:07 | TITLE_614908878 | IMAGE_1362210487 |
+------------+---------------------+------------------+------------------+
40 rows in set (0.01 sec)
Tout fonctionne comme je l'ai publié avant même avec un plus grand nombre d'images. Voici la requête de la procédure stockée ShowLast40 :
SELECT
AAA.author_id,
AAA.date_created,
IFNULL(BBB.title,'<NO_TITLE>') title,
IFNULL(CCC.filename,'<NO-IMAGE>') filename
FROM
(
SELECT
AA.id,
AA.date_added,
BB.author_id,
BB.date_created
FROM
(
SELECT
A.id,IFNULL(MAX(B.date_added),'1900-01-01 00:00:00') date_added
FROM (SELECT id FROM articles ORDER BY date_created DESC LIMIT 40) A
LEFT JOIN article_images B ON A.id = B.article_id
GROUP BY A.id
) AA
INNER JOIN articles BB USING (id)
) AAA
LEFT JOIN article_contents BBB ON AAA.id=BBB.article_id
LEFT JOIN article_images CCC
ON (AAA.id=CCC.article_id AND AAA.date_added=CCC.date_added)
ORDER BY AAA.date_created DESC;
MISE À JOUR 2011-05-17 15:16
Juste pour rire, j'ai augmenté l'échantillon et l'ai relancé. Même vitesse de requête.
mysql> call maketables; call loadsampledata; call showlast40;
Query OK, 0 rows affected (0.38 sec)
+----------------------------------------+
| Results |
+----------------------------------------+
| Articles:1000 Titles:886 Images: 88596 |
+----------------------------------------+
1 row in set (51 min 22.29 sec)
Query OK, 0 rows affected (51 min 22.29 sec)
+------------+---------------------+------------------+------------------+
| author_id | date_created | title | filename |
+------------+---------------------+------------------+------------------+
| 1464539515 | 2004-01-07 22:45:04 | TITLE_676010724 | IMAGE_1877060293 |
| 272558724 | 2004-01-03 23:44:19 | TITLE_1213504045 | IMAGE_550812606 |
| 2000476448 | 2003-12-28 18:05:10 | TITLE_1762951489 | IMAGE_1201290847 |
| 955209697 | 2003-12-25 00:55:43 | TITLE_1064749344 | IMAGE_1335865507 |
| 1657429856 | 2003-12-19 01:03:13 | TITLE_1931852743 | IMAGE_905288424 |
| 759381001 | 2003-11-12 10:46:52 | TITLE_878255772 | IMAGE_2014780795 |
| 1269478951 | 2003-11-06 02:06:22 | TITLE_2026098781 | IMAGE_982272966 |
| 1049672131 | 2003-10-04 20:55:34 | TITLE_2043080215 | IMAGE_987859662 |
| 1429108729 | 2003-09-16 19:07:52 | TITLE_424483080 | IMAGE_35379150 |
| 1672198676 | 2003-09-13 11:49:52 | TITLE_1131552745 | IMAGE_875049630 |
| 1645878842 | 2003-08-24 13:42:04 | TITLE_1077302833 | IMAGE_702269538 |
| 172347180 | 2003-08-21 14:26:37 | TITLE_558691044 | IMAGE_1091183587 |
| 1137674509 | 2003-08-15 08:44:37 | TITLE_1982979709 | IMAGE_1234487941 |
| 282998112 | 2003-08-05 10:01:34 | TITLE_353831568 | IMAGE_738487608 |
| 246145344 | 2003-08-02 00:42:31 | TITLE_376954044 | IMAGE_1279375459 |
| 218409162 | 2003-07-14 02:55:16 | TITLE_1932540991 | IMAGE_1078689211 |
| 593263087 | 2003-07-12 22:47:01 | TITLE_1604012533 | IMAGE_834822870 |
| 2115914174 | 2003-07-06 03:06:31 | TITLE_1268165545 | IMAGE_1068632322 |
| 552557275 | 2003-07-01 16:45:22 | TITLE_2022112717 | IMAGE_1410588295 |
| 1500437041 | 2003-06-29 20:05:19 | TITLE_35559258 | IMAGE_159953586 |
| 1098371257 | 2003-06-09 07:29:37 | TITLE_1694076415 | IMAGE_1409619391 |
| 1570373503 | 2003-05-22 16:45:04 | TITLE_125157894 | IMAGE_723393492 |
| 1330507411 | 2003-05-05 21:40:07 | TITLE_1571250589 | IMAGE_701840418 |
| 1666035620 | 2003-04-26 02:51:40 | TITLE_504713706 | IMAGE_1410357553 |
| 1458179791 | 2003-04-19 05:34:25 | <NO_TITLE> | <NO-IMAGE> |
| 1365758305 | 2003-03-28 10:09:58 | TITLE_704554170 | IMAGE_2085080137 |
| 2131082774 | 2003-03-26 16:43:25 | TITLE_1411034929 | IMAGE_303539208 |
| 103396632 | 2003-02-14 09:11:28 | TITLE_915927396 | IMAGE_1381045723 |
| 396479202 | 2003-02-01 15:51:40 | <NO_TITLE> | <NO-IMAGE> |
| 2019916250 | 2003-01-30 00:44:46 | <NO_TITLE> | <NO-IMAGE> |
| 431091906 | 2003-01-29 13:08:37 | <NO_TITLE> | <NO-IMAGE> |
| 705166549 | 2003-01-23 21:37:07 | TITLE_1530318643 | IMAGE_257673696 |
| 1278327049 | 2002-12-31 16:39:40 | TITLE_772845324 | IMAGE_1355754913 |
| 1871174528 | 2002-12-30 19:03:40 | TITLE_65725764 | IMAGE_522904938 |
| 611892727 | 2002-12-22 10:19:07 | TITLE_333758274 | IMAGE_734815032 |
| 758497849 | 2002-12-04 15:05:10 | TITLE_129140574 | IMAGE_244407066 |
| 518111034 | 2002-10-17 16:38:10 | TITLE_1976498683 | IMAGE_2008599775 |
| 1737725786 | 2002-10-15 23:52:52 | TITLE_1441053871 | IMAGE_1595265847 |
| 1206055789 | 2002-10-03 22:07:52 | TITLE_562697952 | IMAGE_198940092 |
| 702790153 | 2002-08-31 17:37:16 | TITLE_1788304903 | IMAGE_1212944101 |
+------------+---------------------+------------------+------------------+
40 rows in set (0.01 sec)
Query OK, 0 rows affected (0.01 sec)
MISE À JOUR 2011-05-17 15:40
Voici la nouvelle sortie incluant la date de la dernière image :
mysql> call showlast40;
+------------+---------------------+------------------+------------------+---------------------+
| author_id | date_created | title | filename | image_date |
+------------+---------------------+------------------+------------------+---------------------+
| 1464539515 | 2004-01-07 22:45:04 | TITLE_676010724 | IMAGE_1877060293 | 2003-10-16 02:06:58 |
| 272558724 | 2004-01-03 23:44:19 | TITLE_1213504045 | IMAGE_550812606 | 2003-12-28 07:25:43 |
| 2000476448 | 2003-12-28 18:05:10 | TITLE_1762951489 | IMAGE_1201290847 | 2003-08-31 16:56:01 |
| 955209697 | 2003-12-25 00:55:43 | TITLE_1064749344 | IMAGE_1335865507 | 2003-11-11 18:37:07 |
| 1657429856 | 2003-12-19 01:03:13 | TITLE_1931852743 | IMAGE_905288424 | 2003-09-26 07:20:01 |
| 759381001 | 2003-11-12 10:46:52 | TITLE_878255772 | IMAGE_2014780795 | 2003-09-30 06:54:40 |
| 1269478951 | 2003-11-06 02:06:22 | TITLE_2026098781 | IMAGE_982272966 | 2003-07-28 11:59:10 |
| 1049672131 | 2003-10-04 20:55:34 | TITLE_2043080215 | IMAGE_987859662 | 2003-11-19 05:26:37 |
| 1429108729 | 2003-09-16 19:07:52 | TITLE_424483080 | IMAGE_35379150 | 2003-11-18 22:17:55 |
| 1672198676 | 2003-09-13 11:49:52 | TITLE_1131552745 | IMAGE_875049630 | 2003-06-08 00:42:58 |
| 1645878842 | 2003-08-24 13:42:04 | TITLE_1077302833 | IMAGE_702269538 | 2002-04-02 01:21:49 |
| 172347180 | 2003-08-21 14:26:37 | TITLE_558691044 | IMAGE_1091183587 | 2003-08-13 08:30:22 |
| 1137674509 | 2003-08-15 08:44:37 | TITLE_1982979709 | IMAGE_1234487941 | 2003-12-17 11:53:28 |
| 282998112 | 2003-08-05 10:01:34 | TITLE_353831568 | IMAGE_738487608 | 2003-11-08 22:03:22 |
| 246145344 | 2003-08-02 00:42:31 | TITLE_376954044 | IMAGE_1279375459 | 2003-12-05 02:30:49 |
| 218409162 | 2003-07-14 02:55:16 | TITLE_1932540991 | IMAGE_1078689211 | 2003-07-14 15:59:37 |
| 593263087 | 2003-07-12 22:47:01 | TITLE_1604012533 | IMAGE_834822870 | 2003-09-02 05:48:22 |
| 2115914174 | 2003-07-06 03:06:31 | TITLE_1268165545 | IMAGE_1068632322 | 2003-04-28 16:29:01 |
| 552557275 | 2003-07-01 16:45:22 | TITLE_2022112717 | IMAGE_1410588295 | 2003-11-01 01:55:16 |
| 1500437041 | 2003-06-29 20:05:19 | TITLE_35559258 | IMAGE_159953586 | 2003-08-02 10:34:07 |
| 1098371257 | 2003-06-09 07:29:37 | TITLE_1694076415 | IMAGE_1409619391 | 2004-01-07 01:00:13 |
| 1570373503 | 2003-05-22 16:45:04 | TITLE_125157894 | IMAGE_723393492 | 2003-09-26 23:22:43 |
| 1330507411 | 2003-05-05 21:40:07 | TITLE_1571250589 | IMAGE_701840418 | 2003-11-19 20:57:31 |
| 1666035620 | 2003-04-26 02:51:40 | TITLE_504713706 | IMAGE_1410357553 | 2003-11-18 01:30:04 |
| 1458179791 | 2003-04-19 05:34:25 | <NO_TITLE> | <NO-IMAGE> | <NO-IMAGE-DATE> |
| 1365758305 | 2003-03-28 10:09:58 | TITLE_704554170 | IMAGE_2085080137 | 2003-11-11 16:35:19 |
| 2131082774 | 2003-03-26 16:43:25 | TITLE_1411034929 | IMAGE_303539208 | 2003-05-14 12:59:37 |
| 103396632 | 2003-02-14 09:11:28 | TITLE_915927396 | IMAGE_1381045723 | 2003-12-28 18:26:28 |
| 396479202 | 2003-02-01 15:51:40 | <NO_TITLE> | <NO-IMAGE> | <NO-IMAGE-DATE> |
| 2019916250 | 2003-01-30 00:44:46 | <NO_TITLE> | <NO-IMAGE> | <NO-IMAGE-DATE> |
| 431091906 | 2003-01-29 13:08:37 | <NO_TITLE> | <NO-IMAGE> | <NO-IMAGE-DATE> |
| 705166549 | 2003-01-23 21:37:07 | TITLE_1530318643 | IMAGE_257673696 | 2003-08-23 19:06:22 |
| 1278327049 | 2002-12-31 16:39:40 | TITLE_772845324 | IMAGE_1355754913 | 2003-12-22 16:40:25 |
| 1871174528 | 2002-12-30 19:03:40 | TITLE_65725764 | IMAGE_522904938 | 2003-09-06 07:08:01 |
| 611892727 | 2002-12-22 10:19:07 | TITLE_333758274 | IMAGE_734815032 | 2003-09-22 19:16:43 |
| 758497849 | 2002-12-04 15:05:10 | TITLE_129140574 | IMAGE_244407066 | 2003-07-15 12:38:37 |
| 518111034 | 2002-10-17 16:38:10 | TITLE_1976498683 | IMAGE_2008599775 | 2004-01-06 16:37:34 |
| 1737725786 | 2002-10-15 23:52:52 | TITLE_1441053871 | IMAGE_1595265847 | 2003-11-24 15:23:10 |
| 1206055789 | 2002-10-03 22:07:52 | TITLE_562697952 | IMAGE_198940092 | 2003-08-23 11:56:46 |
| 702790153 | 2002-08-31 17:37:16 | TITLE_1788304903 | IMAGE_1212944101 | 2003-12-19 22:56:01 |
+------------+---------------------+------------------+------------------+---------------------+
40 rows in set (0.01 sec)
Voici la nouvelle requête
SELECT
AAA.author_id,
AAA.date_created,
IFNULL(BBB.title,'<NO_TITLE>') title,
IFNULL(CCC.filename,'<NO-IMAGE>') filename,
IFNULL(CCC.date_added,'<NO-IMAGE-DATE>') image_date
FROM
(
SELECT
AA.id,
AA.date_added,
BB.author_id,
BB.date_created
FROM
(
SELECT
A.id,IFNULL(MAX(B.date_added),'1900-01-01 00:00:00') date_added
FROM (SELECT id FROM articles ORDER BY date_created DESC LIMIT 40) A
LEFT JOIN article_images B ON A.id = B.article_id
GROUP BY A.id
) AA
INNER JOIN articles BB USING (id)
) AAA
LEFT JOIN article_contents BBB ON AAA.id=BBB.article_id
LEFT JOIN article_images CCC
ON (AAA.id=CCC.article_id AND AAA.date_added=CCC.date_added)
ORDER BY AAA.date_created DESC;
Ma requête fait une chose que personne d'autre ne fait :
Ma requête obtient d'abord les 40 derniers articles avant de se joindre à une autre table.
Les requêtes de tous les autres rejoignent tout en premier, puis tentent de faire LIMIT 40 sur une grande table temporaire.
Le temps d'exécution de ma requête n'est pas un facteur de la quantité de données.
Quelle que soit la taille de l'échantillon que je crée, ma requête doit être la plus rapide !!!
