Question

I’m using MySQL inside PHP.
I have an SQL table that looks something like this:

id | category_id | date
-----------------------------
1  | 3           | 2012-09-12
2  | 4           | 2012-10-25
3  | 3           | 2012-10-12
4  | 3           | 2012-10-02
5  | 4           | 2012-11-03
6  | 3           | 2012-11-02

I’m trying to figure out how can select all dates of the given category if at least one falls within the specified date range, otherwise select none.
For example:
If the date range is from 2012-09-01 to 2012-09-31, then the query should return all rows for category 3 and none for category 4.

Is there a way do this in a single query ?

Thanks!

Answer 1

You do this with a join or in clause:

select t.*
from t join
     (select distinct category_id
      from t
      where date between <datefrom> and <dateto>
     ) tc
     on t.category_id = tc.category_id
order by t.category_id, date