Module pushdown_projections 

Projection pushdown to eliminate unused columns Projection Pushdown Module

This module provides functionality for removing unused column projections from SQL queries. When a subquery selects columns that are never used by the outer query, those columns can be eliminated to reduce data processing.

Ported from sqlglot’s optimizer/pushdown_projections.py

Functions

default_selection

Create a default selection when all others are removed

pushdown_projections

Rewrite SQL AST to remove unused column projections.