# Module mz_expr::canonicalize

source · ## Expand description

Utility functions to transform parts of a single `MirRelationExpr`

into canonical form.

## Functions§

- Canonicalize only the equivalence classes of a join.
- Canonicalize equivalence classes of a join and expressions contained in them.
- Canonicalize predicates of a filter.
- For each equivalence class, it finds the simplest expression, which will be the canonical one. Returns a Map that maps from each expression in each equivalence class to the canonical expression in the same equivalence class.