How to Join to first row
I'll use a concrete, but hypothetical, example.
Each Order normally has only one line item:
Orders:
OrderGUID OrderNumber
========= ============
{FFB2...} STL-7442-1
{3EC6...} MPT-9931-8A
LineItems:
LineItemGUID Order ID Quantity Description
============ ======== ======== =================================
{098FBE3...} 1 7 prefabulated amulite
{1609B09...} 2 32 spurving bearing
But occasionally there …