fix: Single value non-additive pre-aggregation match in views

Author: paveltiunov

packages/cubejs-schema-compiler/src/adapter/PreAggregations.js

@@ -672,7 +672,7 @@ export class PreAggregations {
     return flattenDimensionMembers
       .map(member => (
         { [member.dimension]: PreAggregations.firstNonAliasMember(query, [member])[0] }
-      ));
+      )).reduce((a, b) => ({ ...a, ...b }), {});
   }
 
   static flattenDimensionMembers(query) {

packages/cubejs-schema-compiler/test/integration/postgres/pre-aggregations.test.ts

@@ -173,6 +173,13 @@ describe('PreAggregations', () => {
           timeDimensionReference: createdAt,
           granularity: 'day'
         },
+        uniqueSourceCountRollup: {
+          type: 'rollup',
+          measures: [uniqueSourceCount],
+          dimensions: [source],
+          timeDimension: createdAt,
+          granularity: 'day'
+        },
         forJoin: {
           type: 'rollup',
           dimensionReferences: [id, source]
@@ -458,7 +465,7 @@ describe('PreAggregations', () => {
     view('visitors_view', {
       cubes: [{
         join_path: visitors,
-        includes: ['uniqueSourceCount', 'ratio', 'createdAt', 'signedUpAt']
+        includes: ['uniqueSourceCount', 'ratio', 'createdAt', 'signedUpAt', 'source']
       }]
     });
     `);
@@ -645,6 +652,46 @@ describe('PreAggregations', () => {
     });
   }));
 
+  it('non-additive single value view filter', () => compiler.compile().then(() => {
+    const query = new PostgresQuery({ joinGraph, cubeEvaluator, compiler }, {
+      measures: [
+        'visitors_view.uniqueSourceCount'
+      ],
+      timeDimensions: [{
+        dimension: 'visitors_view.signedUpAt',
+        granularity: 'day',
+        dateRange: ['2017-01-01', '2017-01-30']
+      }],
+      filters: [{
+        dimension: 'visitors_view.source',
+        operator: 'equals',
+        values: ['google']
+      }],
+      timezone: 'America/Los_Angeles',
+      order: [{
+        id: 'visitors_view.createdAt'
+      }],
+      preAggregationsSchema: ''
+    });
+
+    const queryAndParams = query.buildSqlAndParams();
+    console.log(queryAndParams);
+    const preAggregationsDescription = query.preAggregations?.preAggregationsDescription();
+    console.log(preAggregationsDescription);
+    expect((<any>preAggregationsDescription)[0].loadSql[0]).toMatch(/visitors_unique_source_count/);
+
+    return dbRunner.evaluateQueryWithPreAggregations(query).then(res => {
+      expect(res).toEqual(
+        [
+          {
+            visitors_view__signed_up_at_day: '2017-01-05T00:00:00.000Z',
+            visitors_view__unique_source_count: '1'
+          }
+        ]
+      );
+    });
+  }));
+
   it('inherited original sql', () => compiler.compile().then(() => {
     const query = new PostgresQuery({ joinGraph, cubeEvaluator, compiler }, {
       measures: [