Force MySQL to return duplicates from WHERE IN clause without using JOIN/UNION?

Question

This might not be very sensible, but I\'ld like to let MySQL return me the exact duplicate rows if there are duplicate criteria in the WHERE IN clause. Is this

Answer 1

I'm not sure why you want to ban JOIN as its fairly essential to SQL. It's like banning function calls in a functional language.

A good way to solve this is to create a result set containing the ids you want to return and join with it. Here's one way to do it:

SELECT Table1.*
FROM Table1
JOIN (SELECT 1 AS id
      UNION ALL SELECT 2
      UNION ALL SELECT 3
      UNION ALL SELECT 4
      UNION ALL SELECT 5
      UNION ALL SELECT 1
      UNION ALL SELECT 2
      UNION ALL SELECT 5
      UNION ALL SELECT 5) AS T1
ON Table1.id = T1.id

I'm not sure if you have considered this method? It has none of the problems that you seem to be afraid of.

If you ban joins you can't do this unless you use a stored procedure, which I'd say is worse than joining.