Question

以下查询用于提取以下列＆amp;行。

问题是我无法从每个用户ID中提取两行。如果我使用限制，则只获取前两行。

所以我如何为每个唯一用户ID提取两行。

例如：

two rows of userid 222
two rows of userid 122
two rows of userid 367

等等

TEXT OP：

预期产出：

Answer 1

假设 id 是您的用户ID， post_ID 是唯一的。

(SELECT id,name,post,Image,post
    FROM users  
    GROUP BY id
    ORDER BY id
)
UNION
(SELECT id,name,post,Image,post
    FROM users
    WHERE post_ID NOT IN
    (SELECT post_ID
    FROM users  
    GROUP BY id
    ORDER BY id)
    GROUP BY id
    ORDER BY id
)
ORDER BY id, post_ID

请检查我的查询，我得到以下答案：

(
SELECT store_id, `key_id` , `string` , `translate` , `locale`
FROM `core_translate` AS C
GROUP BY `store_id`
ORDER BY `store_id`
)
UNION (

SELECT store_id, `key_id` , `string` , `translate` , `locale`
FROM `core_translate` AS C
WHERE `key_id` NOT
IN (

SELECT `key_id`
FROM `core_translate` AS C
GROUP BY `store_id`
ORDER BY `store_id`
)
GROUP BY `store_id`
ORDER BY C.`store_id`
)
ORDER BY store_id, `key_id`

store_id    key_id  string  translate   locale
0   20  Screensize  Screensize  en_US
0   21  Gender  Gender  en_US
1   1   Size    Size    en_US
1   2   Color   Color   en_US
2   5   Large Image     Large Image     en_US
2   6   Medium Image    Medium Image    en_US
3   10  Manufacturer    Manufacturer    en_US
3   11  Dimensions  Dimensions  en_US
4   15  Description     Description     en_US
4   16  Weight  Weight  en_US

Answer 2

不确定这在mysql上是否可行，但你可以这样做。我假设id是用户ID，而post_ID是唯一的。

修改

尝试解决mysql限制。

select id,name,post_Imagename_small,Image_title,post_ID from users u1 where u1.post_ID in ( select u3.post_ID from ( select u2.post_ID from users u2 where u2.id = u1.id limit 2 ) s u3 ) order by u1.id

编辑2

在答案不起作用的情况下，here对这种查询问题是一个很好的解读，也有各种解决方法。

如何为每个唯一的用户ID提取两行

2 个答案: