Question

这就是我所拥有的。

cmd = New SqlCeCommand("SELECT SUBSTRING(column, 10, 4) AS serial FROM main1 WHERE (SUBSTRING(column, 1, 3) = 'CAR')", cnx)
If cnx.State = ConnectionState.Closed Then cnx.Open()
Dim SerialStr As String
Dim SerialList As New List(Of Integer)
Using sdr As SqlCeDataReader = cmd.ExecuteReader()
    While sdr.Read()
        SerialList.Add(sdr.GetInt32(sdr.GetOrdinal("serial"))) 'I got this from a forum, not sure if it is what I need
    End While
    SerialStr = SerialList.Item(SerialList.Count).ToString
End Using

我尝试从中获取数据的列是主键，这是格式：

CAR2014-S0001

CAR2014-S0007

PAR2014-S0001

CAR2014-S0004

PAR2014-S0002

等

正如您所看到的，他们并没有按顺序排列。我需要从查询中获取每个数字的最后四位数，对它们进行排序，得到最后一个并将其分配给变量。

Answer 1

这样做：

cmd = New SqlCeCommand("SELECT max(right(column, 4)) AS serial FROM main1 WHERE (SUBSTRING(column, 1, 3) = 'CAR')", cnx)
If cnx.State = ConnectionState.Closed Then cnx.Open()
Dim SerialStr As String = cmd.ExecuteScalar()

我需要从SQL查询中获取最大值并将其保存到变量中

1 个答案: