C# code for Advance Search

A slight bit of overkill in this simple case but I've used code similar to this in the past.

Create a function

string AddCondition(string clause, string appender, string condition)
{
    if (clause.Length <= 0)
    {
        return String.Format("WHERE {0}",condition);
    }
    return string.Format("{0} {1} {2}", clause, appender, condition);
}

Use it like this

string query = "SELECT * FROM Table1 {0}";
string whereClause = string.Empty;

if (condition 1)
    whereClause = AddCondition(whereClause, "AND", "Col=1");

if (condition 2)
    whereClause = AddCondition(whereClause, "AND", "Col2=2");

string finalQuery = String.Format(query, whereClause);

This way if no conditions are found you don't even bother loading a where statement in the query and save the sql server a micro-second of processing the junk where clause when it parses the sql statement.