How to use wildcards in SQL query with parameters

Question

Say I have a basic query, something like this:

 SELECT holiday_name
 FROM holiday
 WHERE holiday_name LIKE %Hallow%

This executes fine in m

Answer 1

First off, your SqlParameter name is @name not name.

Second, I would move your wildcards.

So it would look like this:

string CommandText = "SELECT holiday_name "
               + "FROM holiday "
               + "WHERE holiday_name LIKE @name;"
Connection = new SqlConnection(ConnectionString);

try
{
  var escapedForLike = HolidatyTextBox.Text; // see note below how to construct 
  string searchTerm = string.Format("%{0}%", escapedForLike);
  Connection.Open();
  Command = new SqlCommand(CommandText, Connection);
  Command.Parameters.Add(new SqlParameter("@name", searchTerm));
  var results = Command.ExecuteScalar();
}

Note that LIKE requires special care when passing parameters and you need to escape some characters Escaping special characters in a SQL LIKE statement using sql parameters.