vb.net 使用 VB 从 Access 数据库中检索一列工资的总和
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Using VB to retrieve the sum of a column of salaries from an Access database
提问by user2155190
I have been sitting here with five other guys trying out how to total values from a column. We have scoured Google, but none of the code we've found works.
我和其他五个人坐在这里，尝试如何从一列中求和。我们已经搜索过谷歌，但我们发现的代码都不起作用。
Here is my form:
这是我的表格：
Here is the code I have thus far:
这是我迄今为止的代码：
Public Class frmTotal
Dim dt As New DataTable()
Dim rowindex As Integer = 0
Dim connstr As String = "provider=microsoft.jet.oledb.4.0;" & "data source=valleyfair.mdb"
Dim sqlstr As String = "select * from employee"
Private Sub btnTotal_Click(sender As System.Object, e As System.EventArgs) Handles btnTotal.Click
End Sub
Private Sub frmTotal_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
dt.Clear()
Dim dataAdapter As New OleDb.OleDbDataAdapter(sqlstr, connstr)
dataAdapter.Fill(dt)
dataAdapter.Dispose()
End Sub
End Class
回答by Mitch Wheat
You can either sum in the TSQL or in code. Here's the TSQL version:
您可以在 TSQL 或代码中求和。这是 TSQL 版本：
select *, SUM(MyColumnName) AS TotalMyColumnName
from employee
If you only want the sum then only retrieve the sum and not the other columns
如果您只想要总和，则只检索总和而不是其他列
select SUM(MyColumnName) AS TotalMyColumnName
from employee
回答by Simon Jensen
I'm a rookie at SQL but this is one way i imagine it to be done: 1: Declare variables needed. 2: Fetch needed data from database and save it in a database container. The code only gets values in the column salary. (Unsure what you named it but you could just edit it) 3: using a for loop to add all the numbers together.
我是 SQL 的新手，但这是我想象的一种方法：1：声明需要的变量。2：从数据库中获取需要的数据并保存在数据库容器中。该代码只获取列salary 中的值。（不确定你的名字是什么，但你可以编辑它） 3：使用 for 循环将所有数字加在一起。
If you are using oleDB just change whenever it says SQL to OleDB and it should work just the same
如果您使用的是 oleDB，只需在它对 OleDB 说 SQL 时进行更改，它的工作方式应该相同
Dim Result As Integer = 0
Dim salaryDB As New DataTable
Dim sSQL As String = String.Empty
Dim conn As New SqlClient.SqlConnection
Dim cmd As New SqlClient.SqlCommand
Dim da As New SqlClient.SqlDataAdapter
Public Sub GetSum()
Try
conn = New SqlClient.SqlConnection(Constr)
conn.Open()
cmd.Connection = conn
cmd.CommandType = CommandType.Text
sSQL = "SELECT salary FROM Employee"
cmd.CommandText = sSQL
da.SelectCommand = cmd
da.Fill(salaryDB)
If dtActive.Rows.Count = 0 Then
MsgBox("No record found!")
End If
Catch ex As Exception
MsgBox(ErrorToString)
Finally
conn.Close()
End Try
For Each Row As DataRow In salaryDB.Rows
Result = Result + row(0) 'row is the current row selected and 0 is the column number
Next
End Sub
