sql - 从日期范围生成天数

Question

我想运行这样的查询

select ... as days where `date` is between '2010-01-20' and '2010-01-24'

并返回数据，例如:

days
----------
2010-01-20
2010-01-21
2010-01-22
2010-01-23
2010-01-24

Answer 1

此解决方案不使用循环、过程或临时表。子查询生成最近 10,000 天的日期，并且可以扩展到您希望的向后或向前。

select a.Date 
from (
    select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a) + (1000 * d.a) ) DAY as Date
    from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as a
    cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as b
    cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as c
    cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as d
) a
where a.Date between '2010-01-20' and '2010-01-24' 

输出:

Date
----------
2010-01-24
2010-01-23
2010-01-22
2010-01-21
2010-01-20

性能说明

测试一下 here ，性能出奇的好:上面的查询需要 0.0009 秒。

如果我们扩展子查询以生成大约。 100,000 个数字(因此大约有 274 年的日期)，它的运行时间为 0.0458 秒。

顺便说一句，这是一种非常可移植的技术，只需稍作调整即可适用于大多数数据库。

SQL Fiddle example returning 1,000 days