Question

For example I have the following query (see How to produce a result set based on the comparison of values between two fields?):

select id,
       case nickname when '' then full_name else nickname end as new_name
from your_table

I’m getting a syntax error when I add the last line

select id,
       case nickname when '' then full_name else nickname end as new_name
from your_table
where new_name = 'Jen'

Can I filter out the result set with a WHERE statement?

Answer 1

You’ll need to use a subquery:

select t.id, t.new_name from
(select id,
   case nickname when '' then full_name else nickname end as new_name
from your_table) t
where t.new_name = 'Jen'