Mysql左外连接限制？

这里是我的查询Mysql左外连接限制？

SELECT `t`.`id` AS `t0_c0` 
, `news`.`id` AS `t2_c0` 
, `news`.`title` AS `t2_c1` 
, `news`.`url` AS `t2_c2` 
, `news`.`date` AS `t2_c3` 
, `news`.`hash` AS `t2_c4` 
, `news`.`list_id` AS `t2_c5` 
FROM 
`words` `t` 
LEFT OUTER JOIN `words_news` `news_news` 
ON (`t`.`id` = `news_news`.`word_id`) 
LEFT OUTER JOIN `news` `news` 
ON (`news`.`id` = `news_news`.`news_id`) 
WHERE 
    (`t`.`id` IN (8229, 8574, 7901))

，我需要从news表只选择5日消息，但不知道怎么了，我应该怎么写查询？

来源

2012-08-16 teMkaa

试试这个：

SELECT `t`.`id` AS `t0_c0` 
    , `news`.`id` AS `t2_c0` 
    , `news`.`title` AS `t2_c1` 
    , `news`.`url` AS `t2_c2` 
    , `news`.`date` AS `t2_c3` 
    , `news`.`hash` AS `t2_c4` 
    , `news`.`list_id` AS `t2_c5` 
FROM 
    `words` `t` 
LEFT OUTER JOIN `words_news` `news_news` 
ON (`t`.`id` = `news_news`.`word_id`) 
LEFT OUTER JOIN (SELECT * FROM `news` LIMIT 5) `news` 
ON (`news`.`id` = `news_news`.`news_id`) 
WHERE 
    (`t`.`id` IN (8229, 8574, 7901));

或

SELECT `t`.`id` AS `t0_c0` 
, `news`.`id` AS `t2_c0` 
, `news`.`title` AS `t2_c1` 
, `news`.`url` AS `t2_c2` 
, `news`.`date` AS `t2_c3` 
, `news`.`hash` AS `t2_c4` 
, `news`.`list_id` AS `t2_c5` 
FROM 
    `words` `t` 
LEFT OUTER JOIN `words_news` `news_news` 
ON (`t`.`id` = `news_news`.`word_id`) 
LEFT OUTER JOIN `news` `news` 
ON (`news`.`id` = `news_news`.`news_id`) 
JOIN (SELECT @var_ctr := 0) a 
WHERE IF(`news`.`id` IS NOT NULL, @var_ctr := @var_ctr + 1, @var_ctr) <= 5 
     AND (`t`.`id` IN (8229, 8574, 7901));

来源

2012-08-16 10:44:04 Omesh

没有工作，所有选中的行为空！ – teMkaa 2012-08-16 10:48:44

尝试新的更新的查询。 – Omesh 2012-08-16 10:54:52

您错过了“@var_ctr”<= 5“后，但无论如何，它只选择了1个字（最后一个ID为7901）和5条新闻，所以我认为我们非常接近正确的查询！感谢您的帮助！ – teMkaa 2012-08-16 11:05:06

Mysql左外连接限制？

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