Both these statements Decode and Case will work similar to the if-then-else statement and also they are the alternatives for each of them. These functions are used in Oracle for data value transformation.
Example:
Decode function
Select OrderNum,
DECODE (Status,’O’, ‘Ordered’,’P’, ‘Packed,’ S’,’ Shipped’, ’A’,’Arrived’)
FROM Orders;
Case function
Select OrderNum
, Case(When Status=’O’ then ‘Ordered’
When Status =’P’ then Packed
When Status=’ S’ then ’Shipped’
else ’Arrived’) end
FROM Orders;
Both these commands will display Order Numbers with their respective Statuses like this,
Status O= Ordered
Status P= Packed
Status S= Shipped
Status A= Arrived
