Merge pull request #272 from Qrlew/full_outer_join_afteragg

remove coalsce of PU and change to LEFT JOIN after clipping

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Changed
+- removing the coalesce of the privacy unit with since it looses the UNIQUE property and changing the JOIN to left instead of INNER after the clipping.
 
 ## [0.9.14] - 2024-01-30
 ### Added

src/differential_privacy/aggregates.rs

@@ -176,14 +176,11 @@ impl PupRelation {
         let mut input_builder = Map::builder()
             .with((
                 self.privacy_unit(),
-                Expr::coalesce(
-                    Expr::cast_as_text(Expr::col(self.privacy_unit())),
-                    Expr::val(self.privacy_unit_default().to_string()),
-                ),
+                Expr::col(self.privacy_unit())
             ))
             .with((
                 self.privacy_unit_weight(),
-                Expr::coalesce(Expr::col(self.privacy_unit_weight()), Expr::val(0.)),
+                Expr::col(self.privacy_unit_weight())
             ));
 
         let mut group_by_names = vec![];

src/relation/rewriting.rs

@@ -463,7 +463,7 @@ impl Relation {
     pub fn scale(self, entities: &str, named_values: &[(&str, &str)], scale_factors: Relation) -> Self {
         // Join the two relations on the entity column
         let join: Relation = Relation::join()
-            .inner(Expr::val(true))
+            .left_outer(Expr::val(true))
             .on_eq(entities, entities)
             .left_names(
                 self.fields()