Question

Suppose there is a data field education in my table profile, now I want to update education=’01’ where earlier education was ‘BA’ , similarly education=’02’ where education was ‘MD’

So I can do this task like this

update profile set education='01' where education='BA';
update profile set education='02' where education='MD';

My question is can I do this task in one command only like

   update profile set education='01' where education='BA' and set education='02' where education='MD';

This syntax is wrong, please tell me is this possible and how ?
If it is not possible, than also please let me know about it…

Answer 1

You can use a CASE statement in the SET clause, but be careful to include an ELSE case which sets the column to its current value — otherwise, the rows that aren’t matched by the two cases will be set to NULL.

UPDATE profile
SET education = 
  CASE
    WHEN education = 'BA' THEN '01'
    WHEN education = 'MD' THEN '02'
    /* MUST include an ELSE case to set to current value, 
       otherwise the non-matching will be NULLed! */
    ELSE education
  END