sql中的分页实现

1.两种方式

  1.1：row_number() over()函数

  1.2：OFFSET ....FETCH 

        OFFSET { integer_constant | offset_row_count_expression } { ROW | ROWS }

        指定在从查询表达式中开始返回行之前，将跳过的行数。OFFSET 子句的参数可以是大于或等于零的整数或表达式。ROW 和 ROWS 可以互换使用。

        FETCH { FIRST|NEXT } <行计数表达式> { ROW|ROWS } ONLY

      指定在处理 OFFSET 子句后，将返回的行数。FETCH 子句的参数可以是大于或等于 1 的整数或表达式。ROW 和 ROWS 可以互换使用。同样，FIRST 和 NEXT 可以互换使用。

 

每页10条，查询第10页的数据

select * from (select row_number() over(order by U_sortNo) as Rm,* from A01 where u_areacode='130000') as t where 100<Rm and Rm<=110

SELECT A0100,COUNT(1) OVER() AS total
FROM A01
where u_areacode='130000'
ORDER BY U_sortNo
OFFSET 100 ROWS FETCH NEXT 10 ROWS ONLY

说明跳过100行不包括第100条数据，并查出来之后的10的数据，也就是101-110中的十条数据

 

        /// 分页
        /// </summary>
        /// <param name="pageIndex">获取当前页码默认为1</param>
        /// <param name="pageSize">获取每页显示多少条记录</param>
        public string GetUserList(int pageIndex, int pageSize,string orderField, string orderType)
        {
            int count;
            string sql = @"select a.*,b.Title,b.Content from Power_user a
left join Knowledge b on a.ID = b.CreateUserID";
            string strsql = string.Format("select * from ({0}) T_TT  where 1=1 ", sql);
            StringBuilder stringBuilder = new StringBuilder();
            int num = (pageIndex-1) * pageSize;
            int num2 = pageIndex * pageSize;
            string str;
            if (!string.IsNullOrEmpty(orderField))
            {
                str = "Order By " + orderField + " " + orderType;
            }
            else
            {
                str = "order by (select 0)";
            }
            stringBuilder.Append("Select * From (Select ROW_NUMBER() Over (" + str + ")");
            stringBuilder.Append(string.Concat(new object[]
            {
                " As rowNum, * From (",
                strsql,
                ") As T ) As N Where rowNum > ",
                num,
                " And rowNum <= ",
                num2
            }));
            count = System.Convert.ToInt32(SqlHelper.ExecuteScalar(SqlHelper.ConnectionString, CommandType.Text, "Select Count(1) From (" + strsql + ") As t", null)); ;
            DataTable dt = SqlHelper.ExecuteDataTable(SqlHelper.ConnectionString, CommandType.Text, stringBuilder.ToString(), null);
            string Json = JsonConvert.SerializeObject(dt);
             List<Power_User> userModel = SqlHelper.ExecuteClass<Power_User>(SqlHelper.ConnectionString, strsql, null);
            //string b = JsonConvert.SerializeObject(userModel);
            return Json;
        }