Question

I need to loop through a set of values (less than 10) and see if they are in a table. If so, I need to print out all of the record values, but if the item doesn’t exist, I still want it to be included in the printed result, although with NULL or 0 values. So, for example, the following query returns:

select * 
  from ACTOR 
 where ID in (4, 5, 15);

+—-+—————————–+————-+———-+——+

| ID | NAME                        | DESCRIPTION | ORDER_ID | TYPE |

+—-+—————————–+————-+———-+——+

|  4 | [TEST-1]                    |             |        3 | NULL |

|  5 | [TEST-2]                    |             |        4 | NULL |

+—-+—————————–+————-+———-+——+

But I want it to return

+—-+—————————–+————-+———-+——+

| ID | NAME                        | DESCRIPTION | ORDER_ID | TYPE |

+—-+—————————–+————-+———-+——+

|  4 | [TEST-1]                    |             |        3 | NULL |

|  5 | [TEST-2]                    |             |        4 | NULL |

|  15| NULL                        |             |        0 | NULL |

+—-+—————————–+————-+———-+——+

Is this possible?

Answer 1

To get the output you want, you first have to construct a derived table containing the ACTOR.id values you desire. UNION ALL works for small data sets:

SELECT *
  FROM (SELECT 4 AS actor_id
          FROM DUAL
        UNION ALL
        SELECT 5
          FROM DUAL
        UNION ALL
        SELECT 15
          FROM DUAL) x

With that, you can OUTER JOIN to the actual table to get the results you want:

   SELECT x.actor_id,
          a.name,
          a.description,
          a.orderid,
          a.type
     FROM (SELECT 4 AS actor_id
             FROM DUAL
           UNION ALL
           SELECT 5
             FROM DUAL
           UNION ALL
           SELECT 15
             FROM DUAL) x
LEFT JOIN ACTOR a ON a.id = x.actor_id

If there’s no match between x and a, the a columns will be null. So if you want orderid to be zero when there’s no match for id 15:

   SELECT x.actor_id,
          a.name,
          a.description,
          COALESCE(a.orderid, 0) AS orderid,
          a.type
     FROM (SELECT 4 AS actor_id
             FROM DUAL
           UNION ALL
           SELECT 5
             FROM DUAL
           UNION ALL
           SELECT 15
             FROM DUAL) x
LEFT JOIN ACTOR a ON a.id = x.actor_id