'System.IndexOutOfRangeException' followed by 'System.Reflection.TargetInvocationException' - mysql

Question

I always get this 2 errors when executing a query
A first chance exception of type 'System.IndexOutOfRangeException' occurred in MySql.Data.dll
Followed by
A first chance exception of type 'System.Reflection.TargetInvocationException' occurred in mscorlib.dll
This is how I execute my query
Sub Get_Teller_Num(hardware_Add As String)
Check_DB_Con() 'Check if the connection is okay
SQL_Query = "SELECT teller_info.teller_num, service_info.service_num " _
& "FROM service_info " _
& "JOIN teller_info " _
& "ON service_info.service_id = teller_info.teller_id " _
& "WHERE teller_info.hardware_add = " & hardware_Add
Dim MySQL_CMD As New MySqlCommand(SQL_Query, MysqlConn)
Try
MySQL_CMD.Connection.Open()
MySQL_Reader = MySQL_CMD.ExecuteReader()
While MySQL_Reader.Read
teller_Num = MySQL_Reader("teller_info.teller_num")
service_Num = MySQL_Reader("service_info.service_num")
End While
MySQL_Reader.Close()
Catch myerror As MySqlException
Console.WriteLine("Failed to run query: " & myerror.Message)
Finally
MysqlConn.Close()
MysqlConn.Dispose()
End Try
End Sub
As you can see, I am joining another table so I can get certain values to it.

Answer 1

It seems that by adding ALIAS or AS in my WHERE clause and reading it based on it solves the problem.
So instead of this query:
SQL_Query = "SELECT teller_info.teller_num, service_info.service_num " _
& "FROM service_info " _
& "JOIN teller_info " _
& "ON service_info.service_id = teller_info.teller_id " _
& "WHERE teller_info.hardware_add = " & hardware_Add
Change it to (Notice that I create an ALIAS for the fields that I want to get):
SQL_Query = "SELECT teller_info.teller_num AS Teller_Num, service_info.service_num AS Service_Num " _
& "FROM service_info " _
& "JOIN teller_info " _
& "ON service_info.service_id = teller_info.teller_id " _
& "WHERE teller_info.hardware_add = " & hardware_Add
Then, we also need to change the way we read data.
Instead of this:
While MySQL_Reader.Read
teller_Num = MySQL_Reader("teller_info.teller_num")
service_Num = MySQL_Reader("service_info.service_num")
End While
Change it to (Notice that I read them based on the ALIAS that I've given to them):
While MySQL_Reader.Read
teller_Num = MySQL_Reader("Teller_Num")
service_Num = MySQL_Reader("Service_Num")
End While