I’m looking to include a goal line in a graph I’m building, but instead of having a static line in my query (‘78’ as “Goal”) I want a linear line showing changing volume from 0-7800 over 1 month so sort of like (‘y=mx+b’ as ‘Goal’) not sure if this is possible but thought I’d ask!

If your data source is a database like PostgreSQL, you can express your goal as another query you UNION ALL with or as a column in your dataset – depends on how your data looks like.