VisualBasic中的内部联接,带有SQL字符串中的组合框值
当我尝试在SQL字符串中使用组合框值时,Visual Basic中的内部联接出现问题 此代码可用于:VisualBasic中的内部联接,带有SQL字符串中的组合框值,sql,visual-studio-2012,combobox,inner-join,Sql,Visual Studio 2012,Combobox,Inner Join,当我尝试在SQL字符串中使用组合框值时,Visual Basic中的内部联接出现问题 此代码可用于: { Private Sub ComboBoxMatricola_TextChanged(sender As Object, e As EventArgs) Handles ComboBoxMatricola.TextChanged Dim connection As New OleDb.OleDbConnection Dim command As New OleD
{
Private Sub ComboBoxMatricola_TextChanged(sender As Object, e As EventArgs) Handles ComboBoxMatricola.TextChanged
Dim connection As New OleDb.OleDbConnection
Dim command As New OleDb.OleDbCommand
connection.ConnectionString = "PROVIDER = Microsoft.ACE.OLEDB.12.0; Data Source = DBManutenzione.accdb"
connection.Open()
Dim SqlCmd = "SELECT DatiManutenzione.Fase, DatiManutenzione.IDGrandezza, DatiManutenzione.FrequenzaGrandezza, DatiManutenzione.Descrizione, DatiManutenzione.FrequenzaTemporale, Macchine.Matricola FROM Macchine INNER JOIN (DatiManutenzione INNER JOIN Manutenzione ON DatiManutenzione.ID = Manutenzione.IDManutenzioneProgrammata) ON Manutenzione.Matricola = Macchine.Matricola"
command = New OleDb.OleDbCommand(SqlCmd, connection)
Dim readerQuery As OleDb.OleDbDataReader
readerQuery = command.ExecuteReader()
Dim Count As Integer
Count = 0
While readerQuery.Read()
Count = Count + 1
End While
MsgBox(Count)
connection.Close()
End Sub
}
当我这样修改SqlCmd时:
...ON Manutenzione.Matricola ='" & ComboBoxMatricola.Text & "'"
我有一个错误:
不支持联接表达式
我必须从组合框中读取ON条件的值
请帮帮我 如果我没弄错的话,你不能在你的
SQL连接中直接这样做,但是在WHERE
条件下有什么方法可以这样做。。取决于您如何应用逻辑
类似于WHERE Macchine.Matricola=ComboBoxMatricola.Text