Hi Anna,

Joining tables always happens on a fixed column, so you'll need to create a column that always contains the value you want to join on.

If like Sebastian suggests only 1 of the Carrier columns is filled in for each row, you can use the Column Manipulations > Concatenate operation. Then select your 4 Carrier columns and use format {0}{1}{2}{3} to get the new value to join on.

If multiple Carrier columns in a row can have a value, you can write a custom operator to add a new column and fill it in with the correct Carrier value based on the Uplink Port column. This tutorial shows the basics of creating a custom operator: DataMiner Docs Custom Operator Tutorial

The code for this custom operator could look something like this:

(Note this is untested code)

[GQIMetaData(Name = "Select carrier")] public class SelectCarrierOperator : IGQIColumnOperator, IGQIRowOperator, IGQIInputArguments
{
// Define input arguments
private readonly GQIColumnDropdownArgument _portColumnArgument = new GQIColumnDropdownArgument("Port column")
{
Types = new[] { GQIColumnType.String },
};

private readonly GQIColumnListArgument _carrierColumnsArgument = new GQIColumnListArgument("Carrier columns")
{
Types = new[] { GQIColumnType.String },
};

// Define output column
private readonly GQIStringColumn _selectedCarrierColumn = new GQIStringColumn("Selected carrier");

// Variables to store the input argument values
private GQIColumn<string> _portColumn;
private GQIColumn<string>[] _carrierColumns;

// Provide the arguments
public GQIArgument[] GetInputArguments() => new GQIArgument[] { _portColumnArgument, _carrierColumnsArgument };

// Retrieve the argument values
public OnArgumentsProcessedOutputArgs OnArgumentsProcessed(OnArgumentsProcessedInputArgs args)
{
_portColumn = (GQIColumn<string>)args.GetArgumentValue(_portColumnArgument);
_carrierColumns = args.GetArgumentValue(_carrierColumnsArgument)
.Cast<GQIColumn<string>>()
.ToArray();

// Do some validation of the argument values
if (_carrierColumns.Length != 4)
throw new GenIfException("Expected exactly 4 carrier columns.");

return default;
}

// Add the output column
public void HandleColumns(GQIEditableHeader header) => header.AddColumns(_selectedCarrierColumn);

public void HandleRow(GQIEditableRow row)
{
// Determine carrier column to use based on the port column
var port = row.GetValue(_portColumn);
var carrierColumn = GetCarrierColumn(port);

// Copy the carrier value to use to the output column
var carrier = row.GetValue(carrierColumn);
row.SetValue(_selectedCarrierColumn, carrier);
}

private GQIColumn<string> GetCarrierColumn(string port)
{
switch (port)
{
case "1": return _carrierColumns[0];
case "2": return _carrierColumns[1];
case "3": return _carrierColumns[2];
default: return _carrierColumns[3];
}
}
}