Question

I currently have a query

SELECT id FROM table1 WHERE {filters on table1} AND id NOT IN (SELECT table1ID FROM table2 WHERE condition = 0)

Table1 has a 1 – Many relationship with table2 and I’m looking for all the IDs that have no entries in table2 with condition=0.

Is there any way to rewrite this query without the inner select? I’m been scratching my head about it for a while now and any pointers would be welcome.

Answer 1

You can try something like

SELECT  id 
FROM    table1 t1 LEFT JOIN
        table2 t2   ON  t1.ID = t2.table1ID
                    AND t2.Condition = 0
WHERE   {filters on table1} 
AND     t2.table1ID IS NULL

Or just as good would be

SELECT  id
FROM    table1 t1
WHERE   {filters on table1} 
AND     NOT EXISTS  (
                        SELECT  1
                        FROM    table2 t2
                        WHERE   t1.ID = t2.table1ID
                        ADN     t2.condition = 0
                    )