Case function with IS Null

How do I implement such scenario in Teradata

If Col1 is null or if Col1 = ''Jack'' then Col2 else Col1

I ha e implemented it but for some reason it's not working may be some issue with Bracketay

2 Answers

You can also use the NULLIF() operator:

COALESCE(NULLIF(col1,'Jack'), col2) 

This is logically equivalent to the CASE statement in the previous answer.

You can use a case expression:

case when col1 is null or col1 = 'Jack' then col2 else col1
end

String (varchar) constants need to be enclosed in sinqle quotes in SQL.