mysql - 从列的求和值中获取总值，MySQL

Question

好的，我两天前了解到这个查询:-

SELECT SUM(DTotal) AS Monthly FROM bdailytotal

但是我如何查看总和的总值(value)？我一直在寻找这个，但我得到的大多数答案都是针对 PHP 的。有人可以告诉我如何将该总值分配给 VB.NET 中的变量吗？

或者教我如何将该总值(value)分配给另一个表。

Answer 1

使用 ExecuteScalar() 尝试类似的操作:

Dim objConn As MySql.Data.MySqlClient.MySqlConnection
Dim objCmd As MySql.Data.MySqlClient.MySqlCommand
Dim strConnString,strSQL As String

strConnString = "Server=localhost;User Id=root; Password=root; Database=mydatabase;"
objConn = New MySql.Data.MySqlClient.MySqlConnection(strConnString)
objConn.Open()

strSQL = "SELECT SUM(DTotal) AS Monthly FROM bdailytotal"

objCmd = New MySql.Data.MySqlClient.MySqlCommand()
With objCmd
.Connection = objConn
.CommandType = CommandType.Text
.CommandText = strSQL
End With

Dim myScalar As Integer = Convert.ToInt32(objCmd.ExecuteScalar())