如何在vb.net中显示数据库中的总行数

Question

编辑我尝试了从helo Ween的评论RecCount，它显示了这个异常RecCount

这是我的代码，x轴工作，但y轴显示这个错误:异常的y轴

我试图使x轴与特定列中的所有相同值。y轴为数据库中的总行数

Dim READER As OleDbDataReader
Try
Dim query As String
query = "SELECT ID, purok  FROM Household"
cmd = New OleDbCommand(query, con)
READER = cmd.ExecuteReader
Dim dT As New DataTable
dT.Load(READER)

Dim counter As String
counter = dT.Rows.Count.ToString

'Dim countrow = Convert.ToInt16(cmd.ExecuteScalar)
'Label3.Text = countrow
Chart1.Series("Purok").XValueMember = "Purok"
Chart1.Series("Purok").YValueMembers = counter
Chart1.DataSource = dT
Chart1.DataBind()
con.Close()
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try

Answer 1

感谢Hel O'Ween的评论和这个线程:"你试图执行一个不包含指定聚合函数的查询";现在修好了。我只是调整并在FROM语句后添加了GROUP BY。

这是结果图表

Dim READER As OleDbDataReader
Try
Dim query As String
query = "SELECT purok, COUNT(*) As RecCount FROM Household GROUP BY purok"
cmd = New OleDbCommand(query, con)
READER = cmd.ExecuteReader
Dim dT As New DataTable
dT.Load(READER)


Chart1.Series("Purok").XValueMember = "purok"
Chart1.Series("Purok").YValueMembers = "RecCount"
Chart1.DataSource = dT
Chart1.DataBind()
con.Close()
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try