MySQL內部加入LIMIT到左表

Question

我有這個數據庫查詢

SELECT *
FROM (`metadata` im)
INNER JOIN `content` ic ON `im`.`rev_id`  = `ic`.`rev_id`
WHERE `im`.`id` = '00039'
AND `current_revision` = 1
ORDER BY `timestamp` DESC
LIMIT 5, 5 

查詢將結果中的總行數限制為5.我希望將左表metadata限制為5，而不限制整個結果集。

我該如何編寫查詢？

Answer 1

如果你考慮一下你想要做什么，你實際上並沒有對metadata進行選擇。

您需要先查詢該子查詢。

嘗試：

SELECT *
FROM ((select * from metadata limit 5) im)
INNER JOIN `content` ic ON `im`.`rev_id`  = `ic`.`rev_id`
WHERE `im`.`id` = '00039'
AND `current_revision` = 1
ORDER BY `timestamp` DESC

Answer 2

這是另一種可能的方法：

SET @serial=0;
SET @thisid=0;

SELECT 
   @serial := IF((@thisid != im.id), @serial + 1, @serial), 
   @thisid := im.id,
   * 
FROM (`metadata` im)
WHERE `im`.`id` = '00039'
AND `current_revision` = 1
AND @serial < 5
ORDER BY `timestamp` DESC

這沒有經過測試。 如果您遇到問題，請告訴我 - 我可以詳細說明。

Answer 3

好吧，我認為你的意思是LEFT JOIN嘗試使用LEFT JOIN而不是INNER JOIN

    SELECT DISTINCT *
    FROM (`metadata` im)
    INNER JOIN `content` ic ON `im`.`rev_id`  = `ic`.`rev_id`
    WHERE `im`.`id` = '00039'
    AND `current_revision` = 1
    ORDER BY `timestamp` DESC
    LIMIT 5, 5