Question

我们说我有3个简单的选择：

select * from `table` order by `id` desc limit 10

select * from `table` order by `date` desc limit 10

select * from `table` order by `name` desc limit 10

是否可以将这三者合并到一个查询中？

谢谢

Answer 1

您可以使用union all：

(select * from `table` order by `id` desc limit 10)
union all
(select * from `table` order by `date` desc limit 10)
union all
(select * from `table` order by `name` desc limit 10);

Answer 2

使用UNION：

(select * from `table` order by `id` desc limit 10) T1
UNION
(select * from `table` order by `date` desc limit 10) T2
UNION
(select * from `table` order by `name` desc limit 10) T3

如果您还需要重复项，请将UNION替换为UNION ALL。

Answer 3

如果您想要一个结果集，只需使用以逗号分隔的列标识符列表order by：

select * from `table` order by `id` desc, `date` desc, `name` desc limit 10

这将按id排序，如果ID相同，则按date排序，如果日期相同，请按name排序。

如果您需要三个结果集，请使用UNION ALL：

(select * from `table` order by `id` desc limit 10)
union all
(select * from `table` order by `date` desc limit 10)
union all
(select * from `table` order by `name` desc limit 10)

在同一张桌子上的多个订单

3 个答案: