如何将数据库中的“ EndDate”与今天的当前日期进行比较？

Question

我想根据EndDate是否是<今天的日期来执行查询。这是我到目前为止的内容，我需要知道如何比较它们。谢谢！

 //Delete from DB Condition (EndDate) if (sqlCon.State == ConnectionState.Closed) sqlCon.Open(); SqlCommand sqlCmd = new SqlCommand("DeleteByDate", sqlCon); sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.ExecuteNonQuery(); sqlCon.Close(); Clear(); 

这是存储过程。

 ALTER PROC [dbo].[DeleteByDate] @AdvID int AS BEGIN UPDATE a SET a.Status = 0 FROM Advertisement a WHERE a.AdvID = @AdvID END 

Answer 1

您可以像这样从C＃或SQL处理它：

C＃

if(EndDate < DateTime.Now.Date)     // Assuming EndDate is already defined in your class 
{
    using(SqlConnection sqlCon = new SqlConnection(sqlCon.ConnectionString) )
    using(SqlCommand sqlCmd = new SqlCommand("DeleteByDate", sqlCon))
    {
        sqlCon.Open();
        sqlCmd.CommandType = CommandType.StoredProcedure;
        sqlCmd.Parameters.Add("@AdvID", SqlDbType.Int);
        sqlCmd.Parameters["@AdvID"].Value = AdvID //Assuming it's already defined;
        sqlCmd.ExecuteNonQuery();   
    }   
}

SQL：

ALTER PROC [dbo].[DeleteByDate]
@AdvID int
AS
BEGIN

    DECLARE @CurrentDate DATE = GETDATE() -- to get current date

    -- Assuming that Advertisement table has the column EndDate
    IF EXISTS (SELECT * FROM Advertisement a WHERE a.EndDate < @CurrentDate )
    BEGIN 
        UPDATE a SET a.Status = 0
        FROM Advertisement a
        WHERE a.AdvID = @AdvID  
    END 
END

如果使用C＃，它将直到满足条件时才触发sp，但是在SQL中，它将使C＃触发sp，并且sp会在每次代码运行时检查条件。

因此，这取决于您的应用程序结构，首先是应用程序还是数据库，这是您要走的路。