SQL Server: use CASE with LIKE

Question

I am pretty new to SQL and hope someone here can help me with this.

I have a stored procedure where I would like to pass a different value depending on whether a column contains a certain country or not.

So far I only used CASE when checking for the match with a specific number or value so I am not sure about this one. Can someone tell me if the following is valid and correct or let me know how to write this properly (just regarding the part in brackets) ?

(CASE countries      WHEN LIKE '%'+@selCountry+'%' THEN 'national'      ELSE 'regional') AS validity 

Notes: @selCountry is the variable name of a country, countries can either be empty, one country or several countries separated with comma and space. Basically I just want to check if countries contains @selCountry and if yes, set validity to 'national'.

Answer 1

This is the syntax you need:

CASE WHEN countries LIKE '%'+@selCountry+'%' THEN 'national' ELSE 'regional' END 

Although, as per your original problem, I'd solve it differently, splitting the content of @selcountry int a table form and joining to it.