public override string ToSql()
 {
     if (LogicOp == LogicOpType.并且)
     {
         return("(" + Condition1.ToSql() + " AND " + Condition2.ToSql() + ")");
     }
     else
     {
         return("(" + Condition1.ToSql() + " OR " + Condition2.ToSql() + ")");
     }
 }