PG: Support for multiple projection in aggregate (#4469)

Author: dplewis

spec/ParseQuery.Aggregate.spec.js

@@ -254,7 +254,8 @@ describe('Parse.Query Aggregate testing', () => {
     rp.get(Parse.serverURL + '/aggregate/TestObject', options)
       .then((resp) => {
         resp.results.forEach((result) => {
-          expect(result.name !== undefined).toBe(true);
+          expect(result.objectId).not.toBe(undefined);
+          expect(result.name).not.toBe(undefined);
           expect(result.sender).toBe(undefined);
           expect(result.size).toBe(undefined);
           expect(result.score).toBe(undefined);
@@ -263,6 +264,25 @@ describe('Parse.Query Aggregate testing', () => {
       }).catch(done.fail);
   });
 
+  it('multiple project query', (done) => {
+    const options = Object.assign({}, masterKeyOptions, {
+      body: {
+        project: { name: 1, score: 1, sender: 1 },
+      }
+    });
+    rp.get(Parse.serverURL + '/aggregate/TestObject', options)
+      .then((resp) => {
+        resp.results.forEach((result) => {
+          expect(result.objectId).not.toBe(undefined);
+          expect(result.name).not.toBe(undefined);
+          expect(result.score).not.toBe(undefined);
+          expect(result.sender).not.toBe(undefined);
+          expect(result.size).toBe(undefined);
+        });
+        done();
+      }).catch(done.fail);
+  });
+
   it('project with group query', (done) => {
     const options = Object.assign({}, masterKeyOptions, {
       body: {

src/Adapters/Storage/Postgres/PostgresStorageAdapter.js

@@ -1552,7 +1552,7 @@ export class PostgresStorageAdapter implements StorageAdapter {
       }
     }
 
-    const qs = `SELECT ${columns.join(',')} FROM $1:name ${wherePattern} ${sortPattern} ${limitPattern} ${skipPattern} ${groupPattern}`;
+    const qs = `SELECT ${columns.join()} FROM $1:name ${wherePattern} ${sortPattern} ${limitPattern} ${skipPattern} ${groupPattern}`;
     debug(qs, values);
     return this._client.map(qs, values, a => this.postgresObjectToParseObject(className, a, schema))
       .then(results => {