fix(griffin): when forming execution plan group-by key could get ignored in sub-queries (#752)

core/src/main/java/io/questdb/griffin/SqlOptimiser.java

@@ -2177,6 +2177,18 @@ class SqlOptimiser {
             }
         }
 
+        // If this is group by model we need to add all non-selected keys, only if this is sub-query
+        // For top level models top-down column list will be empty
+        if (model.getSelectModelType() == QueryModel.SELECT_MODEL_GROUP_BY && model.getTopDownColumns().size() > 0) {
+            final ObjList<QueryColumn> bottomUpColumns = model.getBottomUpColumns();
+            for (int i = 0, n = bottomUpColumns.size(); i < n; i++) {
+                QueryColumn qc = bottomUpColumns.getQuick(i);
+                if (qc.getAst().type != FUNCTION || !functionParser.isGroupBy(qc.getAst().token)) {
+                    model.addTopDownColumn(qc, qc.getAlias());
+                }
+            }
+        }
+
         // latest by
         emitLiteralsTopDown(model.getLatestBy(), model);
 

core/src/test/java/io/questdb/griffin/SqlParserTest.java

@@ -49,6 +49,15 @@ public class SqlParserTest extends AbstractGriffinTest {
         );
     }
 
+    @Test
+    public void testGroupByTimeInSubQuery() throws SqlException {
+        assertQuery(
+                "select-group-by min(s) min, max(s) max, avg(s) avg from (select-group-by [sum(value) s, ts] ts, sum(value) s from (select [value, ts] from erdem_x timestamp (ts)))",
+                "select min(s), max(s), avg(s) from (select ts, sum(value) s from erdem_x)",
+                modelOf("erdem_x").timestamp("ts").col("value", ColumnType.LONG)
+        );
+    }
+
     @Test
     public void testAliasWithSpace() throws Exception {
         assertQuery("select-choose x from (select [x] from x 'b a' where x > 1) 'b a'",
@@ -4674,7 +4683,7 @@ public class SqlParserTest extends AbstractGriffinTest {
 
     @Test
     public void testSelectGroupByUnion() throws SqlException {
-        assertQuery("select-choose b from (select-group-by [sum(b) b] a, sum(b) b from (select [b] from trips) union all select-group-by [avg(d) b] c, avg(d) b from (select [d] from trips))",
+        assertQuery("select-choose b from (select-group-by [sum(b) b, a] a, sum(b) b from (select [b, a] from trips) union all select-group-by [avg(d) b, c] c, avg(d) b from (select [d, c] from trips))",
                 "select b from (select a, sum(b) b from trips union all select c, avg(d) b from trips)",
                 modelOf("trips")
                         .col("a", ColumnType.INT)