Question

这是我的SQL查询（我正在使用SQL Server Management Studio）和C＃进行开发。

代码完美无缺。但我只想计算受影响的行数。

我已经尝试了几个计数等步骤但是它没有用。

SELECT     
   LevelDetails.App_ID, LevelDetails.Intro_ID, LevelDetails.Side, 
   LevelDetails.SLevel, 
   Top_up_details.topupdate, Top_up_details.Recharge_epin, 
   Top_up_details.epin, Top_up_details.app_id AS Expr1
FROM
   LevelDetails 
INNER JOIN
   Top_up_details ON LevelDetails.App_ID = Top_up_details.app_id
WHERE     
   (LevelDetails.Intro_ID = '1001')

Answer 1

试试这个：

SELECT count(*)
FROM LevelDetails INNER JOIN Top_up_details 
                  ON LevelDetails.App_ID = Top_up_details.app_id
WHERE     (LevelDetails.Intro_ID = '1001')

Answer 2

你看起来像这样吗。

您可以添加COUNT(LevelDetails.App_ID) OVER() As rowcount以及为您提供总行数的选择部分。

SELECT     
   LevelDetails.App_ID, LevelDetails.Intro_ID, LevelDetails.Side, 
   LevelDetails.SLevel, 
   Top_up_details.topupdate, Top_up_details.Recharge_epin, 
   Top_up_details.epin, Top_up_details.app_id AS Expr1,
   COUNT(LevelDetails.App_ID) OVER() As rowcount // gives you the total count also
FROM
   LevelDetails 
INNER JOIN
   Top_up_details ON LevelDetails.App_ID = Top_up_details.app_id
WHERE     
   (LevelDetails.Intro_ID = '1001')

Answer 3

@OP这是您从评论中获取的代码。

dtc = g1.return_dt("SELECT count(*) as app_c FROM LevelDetails 
                    INNER JOIN Top_up_details ON LevelDetails.App_ID = Top_up_details.app_id 
                    WHERE (LevelDetails.Intro_ID = '" + Session["appid"] + "')"); 

if (dtc.Rows.Count > 0) 
{ 
      Session["app_count"] = dt.Rows[0]["app_c"].ToString(); 
}

我认为在上面的代码中您遗漏了Session["appid"].ToString()，但最好在应用null之前检查ToString()。这是一个例子：

 if(Session["appid"] != null)
 {
      dtc = g1.return_dt("SELECT count(*) as app_c FROM LevelDetails 
                    INNER JOIN Top_up_details ON LevelDetails.App_ID = Top_up_details.app_id 
                    WHERE (LevelDetails.Intro_ID = '" + Session["appid"].ToString() + "')"); 

      if (dtc.Rows.Count > 0) 
      { 
               Session["app_count"] = dt.Rows[0]["app_c"].ToString(); 
      }
 }

另一种解决方案：

假设您的DataTable dtc 使用问题中提到的查询，那么您只需检查表格中返回的行数：

string sQuery = @" SELECT     
                       LevelDetails.App_ID, LevelDetails.Intro_ID, LevelDetails.Side, 
                       LevelDetails.SLevel, Top_up_details.topupdate, 
                       Top_up_details.Recharge_epin, Top_up_details.epin, 
                       Top_up_details.app_id AS Expr1
                   FROM
                       LevelDetails 
                   INNER JOIN
                       Top_up_details ON LevelDetails.App_ID = Top_up_details.app_id
                   WHERE     
                       (LevelDetails.Intro_ID = '1001')";

DataTable dtc = g1.return_dt(sQuery);
int iTotalRows = dtc.Rows.Count;

否则，要从数据库中获取计数，您可以使用sqlcommand.ExecuteScalar()

计算sql行

3 个答案: