mysql - 如何为每个唯一用户 ID 提取两行

Question

以下查询用于提取以下列和行。

问题是我无法从每个用户 ID 中提取两行。如果我使用限制，则只获取第一两行。

那么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

文本操作:

预期输出:

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，我从中得到以下答案:

(
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