选择最小日期值并计算日期值？

Question

我有一个名为 "SUMMARYDATA" 的表，其中包含 "STATUSIN,STATUSOUT,LATECOME" 列，我想在“STATUSIN”列上选择最小值。并提出条件：IF MIN(STATUSIN) > "08.00 AM" Then LATECOME = MIN(STATUSIN) - "08.00 AM"。如何选择最小日期值？以及如何计算MIN(STATUSIN) - "08.00 AM"？

这是我显示数据库数据的代码：

    <asp:Repeater ID="rptrSUMMARYDATA" runat="server">
        <HeaderTemplate>
            <table class="table">
                <thead>
                    <tr>
                        <th>IN</th>
                        <th>OUT</th>
                        <th>LATECOME</th>
                    </tr>
                </thead>
                <tbody>
        </HeaderTemplate>
        <ItemTemplate>
            <tr>
                <td><%# Eval("STATUSIN") %></td>
                <td><%# Eval("STATUSOUT") %></td>
                <td><%# Eval("LATECOME") %></td>
            </tr>
        </ItemTemplate>
        <FooterTemplate>
                </tbody>
            </table>
        </FooterTemplate>
    </asp:Repeater>  

这是我在后端的代码：

     private void BindSUMMARYDATARptr()
    {
        String CS = ConfigurationManager.ConnectionStrings["MANHOURConnectionString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(CS))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT * FROM SUMMARYDATA", con))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    DataTable dtDaily = new DataTable();
                    sda.Fill(dtDaily);

                    rptrSUMMARYDATA.DataSource = dtDaily;
                    rptrSUMMARYDATA.DataBind();
                }

            }

        }
    }

Answer 1

你能试试这个吗..

  SELECT  STATUSIN,STATUSOUT, CASE WHEN CAST(STATUSIN AS TIME) > CAST('08:00:00' AS TIME) 
           THEN CONVERT(varchar, dateadd(s, -28800 ,STATUSIN), 108)  END AS LATECOME 
  FROM SUMMARYDATA

Answer 2

从datatable 获取MIN 并使用DateTime.Subtract

var minIN = Convert.ToDateTime(dt.AsEnumerable().Min(row => row["IN"]));
Console.WriteLine($"LATECOME {minIN.Subtract(minIN.Date + new TimeSpan(8, 0, 0))}");

注意：AsEnumerable 是System.Data.DataSetExtensions 的一部分。从 nuget 安装这个包

直接在数据库中更新（我不建议这样做，除非绝对需要）

UPDATE SUMMARYDATA 
  SET LATECOME =  CASE WHEN DATEDIFF(s,DATEADD(HOUR, 8, CAST(CAST((select MIN(STATUSIN) from SUMMARYDATA)  AS DATE) AS DATETIME)),(select MIN(STATUSIN) from SUMMARYDATA)) > 0 THEN
  (CONVERT(TIME,(select MIN(STATUSIN) from SUMMARYDATA)-DATEADD(HOUR, 8, CAST(CAST((select MIN(STATUSIN) from SUMMARYDATA)  AS DATE) AS DATETIME)))) ELSE NULL END

Answer 3

select DATEADD(minute, -iif(CAST(STATUSIN as time) > CAST('08:00' as time), DATEDIFF(MINUTE,CAST('08:00' as time),CAST(STATUSIN as time)) ,0) , STATUSIN) as LATECOME
from SUMMARYDATA

Answer 4

试试这个：

select STATUSIN,STATUSOUT,case when CAST(STATUSIN as time) > CAST('08:00' as time) then 
DATEDIFF(MINUTE,CAST('08:00' as time),CAST(STATUSIN as time)) 
end as LATECOME from test;