What is difference between Decode and Case

 

Decode is function while Case is Statement.

Case cannot process null while decode can process null.

Case is an ANSI standard where as Decode is Oracle proprietary.

SELECT        DECODE(grade,'A','Distinction',                     'B','First Class',                     'C','Second Class',                     'D','Failed',                     'Failed') Per_Grade   FROM grade;

SELECT        CASE grade          WHEN 'A' then 'Distinction'          WHEN 'B' then 'First Class'          WHEN 'C' then 'Second Class'          WHEN 'D' then 'Failed'          Else 'No Grade'        END Per_Grade   FROM Grade;