I was trying to avoid putting everything in the group by, which why i put the invoice_lines columns in a nested select. I orginally had it with the invoice_head columns...

This might be "Concatenating values when the number of items is not known" never done that before.

I worked it out, the problem was the string were delceared as variables.

This works,

([DivisionCode]=="MV"?"Mediavest":([DivisionCode]=="SC"?"Starcom - Non Tech":[DivisionCode]=="SP"?"Starcom - P&G":[DivisionCode]=="ST"?"Starcom - Tech":"Starcom - Non Tech"))