Question

I read about using the CASE expression inside the WHERE clause here:

http://scottelkin.com/sql/using-a-case-statement-in-a-sql-where-clause/

I’m trying to use this to filter results from my select statement, based on a contract number which will be passed in by the user’s application. My code currently throws an error of ‘Invalid parameter’ no matter what is passed in. I verified SELECT/FROM are working fine, as where as a WHERE clause without a CASE expression. Here is my code.

WHERE     (CASE WHEN @ContractNo = 0 THEN @ContractNo ELSE @ContractNo END = tblContracts.ContractNo) 

The redundancy of the code is for troubleshooting purposes, I’m planning on using wildcard filtering on the CASE later. I’m focusing on getting the syntax down right now. I believe this should return all records for which the parameter matches the contract number stored in the table. Any help or advice would be greatly appreciated.

Answer 1

After reading your explanation, there’s a better way to do this without CASE:

WHERE @ContractNo = 0 OR tblContracts.ContractNo = @ContractNo 

This will return only matching contract numbers, unless @ContractNo is 0, in which case it will return all records.

Edit: I’ve just noticed that casperOne proposed the same thing. I didn’t see that. Big up yourself.