mysql - 只显示一列 Datagridview mysql vb.net

Question

我有数据库表 schedule，它有 7 列(ID、Reserve_No、Lastname、Firstname、Service、PhoneNumber、Date_Time)我只想显示列 Date_Time。

这是我在 Datagridview 上显示数据库的代码

Dim DataAdapter As New MySqlDataAdapter
        Dim DataTable As New DataTable
        Dim cmd As New MySqlCommand
        MySqlConn.Open()
        With cmd
            .Connection = MySqlConn
            .CommandText = "SELECT * FROM schedule"
        End With
        DataAdapter.SelectCommand = cmd
        DataTable.Clear()
        DataAdapter.Fill(DataTable)
        DataGridView1.DataSource = DataTable
        MySqlConn.Close()

Answer 1

从 MySQL 表中选择列:

If you do not want to see entire rows from your table, just name the columns in which you are interested, separated by commas.

更改您的查询以选择一列:

    Dim DataAdapter As New MySqlDataAdapter
    Dim DataTable As New DataTable
    Dim cmd As New MySqlCommand
    MySqlConn.Open()
    With cmd
        .Connection = MySqlConn
        .CommandText = "SELECT Date_Time FROM schedule"
    End With
    DataAdapter.SelectCommand = cmd
    DataTable.Clear()
    DataAdapter.Fill(DataTable)
    DataGridView1.DataSource = DataTable
    MySqlConn.Close()

Also you can to minimize the output, retrieve each unique output record just once by adding the keyword DISTINCT.

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