php - if 检查双重记录的条件指令

Question

我有这张表:

如何编写指令 if ，它将检查同时存储的记录(在我的表中是列 created_at )。 例如:

if(created_at for record where key(it's column)='stan' it is the same as created_at for key='stan_key' {
    return records where key='stan'
}

Answer 1

有几个选项。这是使用 exists 的版本:

select * 
from yourtable y1
where y1.key = 'stan' and exists (
    select 1
    from yourtable y2
    where y2.key = 'stan_key' and y1.created_at = y2.created_at)