C# SQL多条件查询拼接技巧

本文转载http://www.cnblogs.com/zfanlong1314/p/3874910.html

#region 多条件搜索时，使用List集合来拼接条件（拼接Sql）

         StringBuilder sql = new StringBuilder("select * from PhoneNum");
         List<string> wheres = new List<string>();
         if (cboGroup.SelectedIndex != 0)
         {
             wheres.Add(" ptypeid=" + cboGroup.Text.Split('|')[0]);
         }

         if (txtSearchName.Text.Trim().Length > 0)
         {
              wheres.Add(" pname like '%" + txtSearchName.Text.Trim() + "%'");
         }

         if (txtSearchCellPhone.Text.Trim().Length > 0)
         {
              wheres.Add(" pcellphone like '%" + txtSearchCellPhone.Text.Trim() + "%'");
         }


         //判断用户是否选择了条件
         if (wheres.Count > 0)
         {
             string wh = string.Join(" and ", wheres.ToArray());
             sql.Append(" where " + wh);
         }
#endregion

 #region 多条件搜索使用带参数的sql语句

         StringBuilder sql = new StringBuilder("select * from PhoneNum");
         List<string> wheres = new List<string>();
         List<SqlParameter> listParameter = new List<SqlParameter>();

         if (cboGroup.SelectedIndex != 0)
         {
             wheres.Add(" ptypeid=@typeid ");
             listParameter.Add(new SqlParameter("@typeid", cboGroup.Text.Split('|')[0]));
         }

         if (txtSearchName.Text.Trim().Length > 0)
         {
             wheres.Add(" pname like @pname ");
             //pname like '%乔%'
             //pname liek '%'+@pname+'%'
             listParameter.Add(new SqlParameter("@pname", "%" + txtSearchName.Text.Trim() + "%"));
         }

         if (txtSearchCellPhone.Text.Trim().Length > 0)
         {
             wheres.Add(" pcellphone like @cellphone ");
             listParameter.Add(new SqlParameter("@cellphone", "%" + txtSearchCellPhone.Text.Trim() + "%"));
         }


         //判断用户是否选择了条件
         if (wheres.Count > 0)
         {
             string wh = string.Join(" and ", wheres.ToArray());
             sql.Append(" where " + wh);
         }



         SqlHelper.ExecuteDataTable(sql.ToString(), listParameter.ToArray());
#endregion