獲取從列的求和值的總價值，MySQL的

Question

好吧，我3天前得知這個查詢： -

SELECT SUM(DTotal) AS Monthly FROM bdailytotal 

，但我要如何查看總和的總價值？我一直在尋找這個，但是我得到的大部分答案都是針對PHP的。有人可以告訴我如何將總價值分配給VB.NET中的變量嗎？

或教我如何將該總值分配給另一個表。

Answer 1

嘗試像這樣與ExecuteScalar()：

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()) 

Answer 2

嘗試以下操作：

While dr.Read() 
Dim monthly = dr("Monthly") 
End While 

MsgBox(monthly)