Join two tables where table A has a date value and needs to find the next date in B below the date in A

Question

I got this table \"A\":

| id | date       |
===================
| 1  | 2010-01-13 |
| 2  | 2011-04-19 |
| 3  | 2011-05-07 |
| .. | ...        |

Answer 1

You could use a subquery with limit 1 to look up the latest value in table B:

select  id
,       date
,       (
        select  value
        from    B
        where   B.date < A.date
        order by
                B.date desc
        limit   1
        ) as value
from    A