AQuery/engine/TODO.md

TODO:

1. double scans in projections

• first for special aggrigations and singular columns
• Then in group by node decide if we have special group by aggregations
• If sp_gb_agg exists, the entire groupby aggregation is done in C plugin
• If not, group by is done in SQL

2. ColRef supports multiple objects

• A.a = B.b then in projection A.a B.b will refer to same projection
• Colref::ProjEq(ColRef v) => this == v or v in this.proj_eqs