How to use LIKE in a t-sql dynamic statement in a stored procedure?

Question

I'm trying to use the LIKE keyword with the % wildcards wrapping the parameter, but I'm not sure how to get the % characters into the statement without breaking it. Right now I have:

SET @SQLQuery = 'SELECT * FROM [tblApps] WHERE [firstName] LIKE %@search%'

I get a SqlException error in my .net app that says "Incorrect syntax near '@search' when I run it. The error goes away if I remove the % characters surrounding the @search parameter.

Answer 1

The % characters have to be in the search string...

SET @search = '%' + @search + '%'
SET @SQLQuery = 'SELECT * FROM [tblApps] WHERE [firstName] LIKE @search'

Note that the following would also work, but introduces potential for a SQL injection vulnerability...

-- DON'T do this!
SET @SQLQuery = 'SELECT * FROM [tblApps] WHERE [firstName] LIKE ''%' + @search + '%'''

Answer 2

SET @SQLQuery = 'SELECT * from [tblApps] WHERE [firstName] LIKE ''%'' + @search + ''%'''
exec sp_executesql @query=@SQLQuery, @params=N'@search nvarchar(96)', @search=@search

The only difference from this version as compared to the others is that the dynamic execution of the sql is in fact parameterized which mitigates sql injection a bit.