Después de revisar las otras respuestas, me ayudó a darme cuenta de un problema subyacente.
La tabla de artículos y la tabla de imágenes de artículos deben tener un índice adicional.
Esto es lo que tienes ahora:
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;
Esto es lo que necesitas:
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;
artículos
El nuevo índice para ordenar los artículos por fecha de inserción en orden descendente
article_images
Todavía se necesita el primer índice, ya que evitará que se adjunte otra imagen con el mismo nombre de archivo a un artículo.
El segundo índice facilitará la búsqueda de la imagen más reciente,
Con esos nuevos índices en su lugar, aquí está la consulta que hará su oferta:
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;
El objetivo es primero crear una subconsulta interna que solo tenga 40 filas. Eso es lo que AA debería traer de vuelta. La subconsulta AAA debe tener la información del artículo más la fecha en que se insertó la última imagen. El último conjunto de uniones debe conectar los 40 ID con un título y una imagen. El paso final es presentar el conjunto de resultados en orden descendente.
Como no tengo datos de muestra, escribí tres procedimientos almacenados en una base de datos de muestra llamada cosas
1 para hacer las tablas
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 $$
DELIMITER ;
1 para hacer los datos
DELIMITER $$
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 para ejecutar la consulta
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 ;
Aquí hay un resultado de ejemplo cuando lo ejecuté en mi escritorio de 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)
Pruébalo !!!
ACTUALIZAR
Me aseguré absolutamente de que las 40 fechas y horas que está leyendo sean, de hecho, las 40 principales. Lo son. Ejecuté la consulta:seleccione * de los artículos ORDENAR POR date_created DESC; para asegurarse.
ACTUALIZACIÓN 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)
Todo funciona como publiqué antes, incluso con un conjunto de imágenes más grande. Aquí está la consulta del procedimiento almacenado 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;
ACTUALIZACIÓN 2011-05-17 15:16
Solo para reír, aumenté la muestra y la volví a ejecutar. Misma velocidad de consulta.
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)
ACTUALIZACIÓN 2011-05-17 15:40
Aquí está la nueva salida, incluida la fecha de la última imagen:
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)
Aquí está la nueva consulta
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;
Mi consulta hace algo que la consulta de nadie más hace:
Mi consulta obtiene primero los últimos 40 artículos antes de unirse a cualquier otra tabla.
Las consultas de todos los demás unen todo primero y luego intentan hacer LIMIT 40 en una tabla temporal grande.
El tiempo de ejecución de mi consulta no es un factor de la cantidad de datos.
Independientemente del tamaño de la muestra que cree, mi consulta tiene que ser la más rápida !!!
