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C# SQL多条件查询拼接技巧

本文转载:http://blog.csdn.net/limlimlim/article/details/8638080

   #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