Using IF ELSE in Oracle

Question

As a web developer, I know how to use the IF ELSE in multiple languages. However, I am learning how to write reports using TOAD for Oracle.

My question is, how do I

Answer 1

You can use Decode as well:

SELECT DISTINCT a.item, decode(b.salesman,'VIKKIE','ICKY',Else),NVL(a.manufacturer,'Not Set')Manufacturer
FROM inv_items a, arv_sales b
WHERE a.co = b.co
      AND A.ITEM_KEY = b.item_key
      AND a.co = '100'
AND a.item LIKE 'BX%'
AND b.salesman in ('01','15')
AND trans_date BETWEEN to_date('010113','mmddrr')
                         and to_date('011713','mmddrr')
GROUP BY a.item, b.salesman, a.manufacturer
ORDER BY a.item

Answer 2

IF is a PL/SQL construct. If you are executing a query, you are using SQL not PL/SQL.

In SQL, you can use a CASE statement in the query itself

SELECT DISTINCT a.item, 
                (CASE WHEN b.salesman = 'VIKKIE'
                      THEN 'ICKY'
                      ELSE b.salesman
                  END), 
                NVL(a.manufacturer,'Not Set') Manufacturer
  FROM inv_items a, 
       arv_sales b
 WHERE  a.co = '100'
   AND a.co = b.co
   AND A.ITEM_KEY = b.item_key   
   AND a.item LIKE 'BX%'
   AND b.salesman in ('01','15')
   AND trans_date BETWEEN to_date('010113','mmddrr')
                      and to_date('011713','mmddrr')
ORDER BY a.item

Since you aren't doing any aggregation, you don't want a GROUP BY in your query. Are you really sure that you need the DISTINCT? People often throw that in haphazardly or add it when they are missing a join condition rather than considering whether it is really necessary to do the extra work to identify and remove duplicates.