Question

Stackoverflowers，我想从MYSQL表中选择并在MYSQL查询的末尾显示ID 54，我制作了以下代码，但它与ORDER冲突：

SELECT * FROM owners WHERE id <= 53
UNION
SELECT * FROM owners WHERE id >= 55
ORDER BY owner
UNION
SELECT * FROM owners WHERE id = 54

我认为即使它有效也很麻烦，你能帮忙吗？

Answer 1

您不能依赖UNION子选择的顺序。另请参阅许多其他Stack Overflow问题，例如：

Weird result with UNION and ORDER BY

这样做：

SELECT * FROM owners
-- Order by "ID category" first
ORDER BY CASE WHEN ID <= 53 THEN 1
              WHEN ID >= 55 THEN 2
              WHEN ID  = 54 THEN 3 END,
-- Then, within "category 55", order by owner, too
         CASE WHEN ID <= 53 THEN ''
              WHEN ID >= 55 THEN owner
              WHEN ID  = 54 THEN '' END

您可能需要稍微调整第二个ORDER BY表达式，因为我不确定您要对owner的排序做什么...

Answer 2

如果您只想将54放在最后，也许您可以将查询缩短为：

SELECT * FROM owners 
WHERE id <= 53 or id >= 55 or id = 54
ORDER BY 
   id = 54, 
   owner

首先进行错误排序，最后进行真正的排序。其他数据库这样做：

SELECT * FROM owners 
WHERE id <= 53 or id >= 55 or id = 54
ORDER BY 
   case when id = 54 then 1 else 0 end, 
   owner

但这很有趣，完全取消了这个条件：

SELECT * FROM owners 

ORDER BY 
   case when id = 54 then 1 else 0 end, 
   owner

Answer 3

关于您的示例，您要从owners中选择所有内容，并最后显示id=54 ~~第一行~~的行。

SELECT * FROM owners 
order by case id when 54 then 1 else 0 end, id

Answer 4

尝试使用括号

(SELECT * FROM owners WHERE id <= 53)
UNION
(SELECT * FROM owners WHERE id >= 55 ORDER BY owner)
UNION
(SELECT * FROM owners WHERE id = 54)

MYSQL SELECT最后有一个条目

4 个答案: