I'm sure the guy knew that. He was curious, as I am, to know where you can buy the cable itself. I don't want to pay iFixit's huge markup for some tools I already have and a glorified paper clip (I mean, "Logic Board Removal Tool").
Update: the part number is 922-9560, available for $30-40 online. If you don't already have the tools, the kit might not be a bad idea.
That cable can be found included in the Mac Mini Dual Hard Drive Kit.
Add a second hard drive to your 2011 or 2012 Mac Mini. Kit includes: SATA Hard Drive Cable, Mounting Grommets, Mounting Screws, Logic Board Removal Tool, 26 Bit Driver Kit, and ESD-Safe Spudger. Compatible with 2.3, 2.5, or 2.7 GHz 2011 Mac Minis (Model A — 50+ available at 29.95 each.