fix(clickhouse): preserve grouped aggregate dimensions

Author: dosco

core/internal/dialect/clickhouse.go

@@ -300,6 +300,15 @@ func (b *chBuilder) collectFields(sel *qcode.Select, n *chNode) error {
 			n.Aggregates = append(n.Aggregates, chAggregate{Fn: f.Func.Name, Col: col, Alias: f.FieldName})
 		}
 	}
+	// Mixed dimension+aggregate selections use the same grouping columns the
+	// shared compiler calculated for SQL dialects. Without this, ClickHouse's
+	// aggregate projection drops regular fields and silently collapses the
+	// result to a single global aggregate row.
+	if sel.GroupCols && !sel.GlobalAgg && len(n.Aggregates) > 0 {
+		for _, col := range sel.BCols {
+			n.GroupBy = ensureCol(n.GroupBy, col.Col.Name)
+		}
+	}
 	for _, dc := range sel.DistinctOn {
 		add(dc.Name)
 		n.GroupBy = append(n.GroupBy, dc.Name)

core/internal/dialect/clickhouse_test.go

@@ -0,0 +1,50 @@
+package dialect
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/dosco/graphjin/core/v3/internal/qcode"
+	"github.com/dosco/graphjin/core/v3/internal/sdata"
+)
+
+func TestClickHouseCollectFieldsGroupsCompilerBaseColumns(t *testing.T) {
+	nameCol := sdata.DBColumn{Name: "name"}
+	sel := &qcode.Select{
+		GroupCols: true,
+		Fields: []qcode.Field{
+			{Type: qcode.FieldTypeCol, Col: nameCol, FieldName: "name"},
+			{Type: qcode.FieldTypeFunc, Func: sdata.DBFunction{Name: "count", Agg: true}, FieldName: "count_id"},
+		},
+		BCols: []qcode.Column{{Col: nameCol}},
+	}
+
+	node := &chNode{}
+	if err := (&chBuilder{}).collectFields(sel, node); err != nil {
+		t.Fatal(err)
+	}
+	if want := []string{"name"}; !reflect.DeepEqual(node.GroupBy, want) {
+		t.Fatalf("group_by = %v, want %v", node.GroupBy, want)
+	}
+	if len(node.Aggregates) != 1 || node.Aggregates[0].Alias != "count_id" {
+		t.Fatalf("aggregates = %+v", node.Aggregates)
+	}
+}
+
+func TestClickHouseCollectFieldsKeepsGlobalAggregateUngrouped(t *testing.T) {
+	sel := &qcode.Select{
+		GroupCols: true,
+		GlobalAgg: true,
+		Fields: []qcode.Field{
+			{Type: qcode.FieldTypeFunc, Func: sdata.DBFunction{Name: "count", Agg: true}, FieldName: "count_id"},
+		},
+	}
+
+	node := &chNode{}
+	if err := (&chBuilder{}).collectFields(sel, node); err != nil {
+		t.Fatal(err)
+	}
+	if len(node.GroupBy) != 0 {
+		t.Fatalf("global aggregate group_by = %v, want none", node.GroupBy)
+	}
+}

tests/query_test.go

@@ -2683,8 +2683,8 @@ func TestResultTruncatedRoots(t *testing.T) {
 		t.Fatalf("limit-clamped list not flagged: %+v", truncated)
 	}
 
-	if dbType == "mongodb" {
-		return // aggregate functions are not supported on the MongoDB harness
+	if dbType == "mongodb" || dbType == "cassandra" {
+		return // aggregate/group queries are not supported on these harnesses
 	}
 
 	res, err = gj.GraphQL(context.Background(),