How to use the case statement in Oracle
The CASE statement can be used in SQL for and IF-THEN-ELSE construction.
It's an alternative for the decode statement and was introduced in Oracle 8.
case( when condition then expr1 [when condition then expr2] ... [else exprN] ) end
Oracle searches for the first when condition that is true.
The expr belonging the this condition is returned.
If Oracle does not find such a condition, the expression belonging to the else statement
is returned. If no else is specified the null value will be returned.
, case (when status ='A' then 'Accepted'
when status ='D' then 'Denied'
else 'Other') end
Will return for each id:
If status = 'A' : 'Accepted'
If status = 'D' : 'Denied'
Else : 'Other'