Use of SqlParameter in SQL LIKE clause not working

Question

I have the following code:

const string Sql =      @"select distinct [name]        from tblCustomers        left outer join tblCustomerInfo on tblCustomers.Id = tblCustomerInfo.CustomerId         where (tblCustomer.Name LIKE '%@SEARCH%' OR tblCustomerInfo.Info LIKE '%@SEARCH%');";  using (var command = new SqlCommand(Sql, Connection)) {            command.Parameters.AddWithValue("@SEARCH", searchString);     ... } 

This does not work, I tried this as well:

const string Sql =      @"select distinct [name]       from tblCustomers       left outer join tblCustomerInfo on tblCustomers.Id = tblCustomerInfo.CustomerId        where (tblCustomer.Name LIKE @SEARCH OR tblCustomerInfo.Info LIKE @SEARCH );";  using (var command = new SqlCommand(Sql, Connection)) {            command.Parameters.AddWithValue("@SEARCH", "'%" + searchString + "%'");     ... } 

but this does not work as well. What is going wrong? Any suggestions?

Answer 1

What you want is:

tblCustomerInfo.Info LIKE '%' + @SEARCH + '%' 

(or edit the parameter value to include the % in the first place).

Otherwise, you are either (first sample) searching for the literal "@SEARCH" (not the arg-value), or you are embedding some extra quotes into the query (second sample).

In some ways, it might be easier to have the TSQL just use LIKE @SEARCH, and handle it at the caller:

command.Parameters.AddWithValue("@SEARCH","%" + searchString + "%"); 

Either approach should work.