สอบถามการ Join สองตาราง VB.net กับฐานข้อมูล Mysql จะทำอย่างไร

SELECT * FROM tbCustomers inner join tbstep on tbCustomers.Step_id= tbstep.Step_id 

         Me._condb.connectDB()
        sb.Remove(0, sb.Length)
        sb.Append(" SELECT * FROM  tbCustomers inner join tbstep on tbCustomers.Step_id = tbstep.Step_id  ")
        Me._condb.da = New MySqlDataAdapter(sb.ToString(), Me._condb.con)
        Me._condb.da.Fill(dsUser, "tbCustomers ")
     

        TbCustomersDataGridView.DataSource = dsUser.Tables("tbCustomers") 'แสดงใน DataGridView

SELECT * FROM tbCustomers inner join tbstep on tbCustomers.Step_id = tbstep.Step_id

Imports MySql.Data
Imports MySql.Data.MySqlClient
Public Class ConnectionDBClass
    Public con As New MySqlConnection
    'Public com As New MySqlCommand
    'Public da As New MySqlDataAdapter
    'Public tr As MySqlTransaction
    'Private Dr As MySqlDataReader
    'Private ds As DataSet
    'Private dt As DataTable
    Public Function connectDB() As Boolean

        If con.State = ConnectionState.Open Then con.Close()

        con.ConnectionString = "Server=localhost;User Id=root; Password=654321; Database=Maintenance; Pooling=false"
        con.Open()
        Return (True)

    End Function
End Class

            Try
               Me._condb.da = New MySqlDataAdapter(sb.ToString(), Me._condb.con)
               Me._condb.da.Fill(dsUser, "tbCustomers ")
            Catch ex As Exception
               msgbox( ex.Message)
            End Try

SELECT * FROM  tbCustomers inner join tbstep on tbCustomers.Step_id = tbstep.Step_id

SELECT * FROM  tbCustomers LEFT JOIN tbstep on tbCustomers.Step_id = tbstep.Step_id