How To Create A Search Query

Code Snippet

CREATE PROCEDURE GetSearchResults
@ParameterValue @varchar(max)
--WITH ENCRYPTION
as
select *
from OPS_Projects
select *
from OPS_Clients

go






I have this stored procedure that has one Parameter ....that parameter value will be a value that can be matched from eithier one of these tables but i am not sure how I need to write query...my logic I would like to read like this

Select * From OPS_Projects Where ThisData = ParameterValue

If this query returns data then, just return that data If not run next query

Select * From OPS_Project Where ThisOtherData = ParameterValue

If this query returns data then, just return that data If not run next query.... and so on....

Is this the best way to do to create a search query???? Any Help I am open for suggestions! Thanks!