Add a temporary fix to grouping records with multi-value fields

Use a distinct count over primary key.

pkg/report/frame.go

@@ -360,6 +360,15 @@ func (cc FrameColumnSet) Find(name string) int {
 	return -1
 }
 
+func (cc FrameColumnSet) FirstPrimary() *FrameColumn {
+	for _, c := range cc {
+		if c.Primary {
+			return c
+		}
+	}
+	return nil
+}
+
 func (cc FrameColumnSet) String() string {
 	out := ""
 	for _, c := range cc {

store/rdbms/ast_transformer.go

@@ -160,6 +160,11 @@ var (
 			Result:  wrapRes("Number"),
 			Handler: makeGenericAggFncHandler("COUNT"),
 		},
+		"distinct": {
+			Args:    collectParams(true, "Any"),
+			Result:  wrapRes("Any"),
+			Handler: makeGenericAggFncHandler("DISTINCT"),
+		},
 		"sum": {
 			Args:    collectParams(true, "Any"),
 			Result:  wrapRes("Number"),

store/rdbms/compose_record_datasource.go

@@ -22,10 +22,6 @@ type (
 		name   string
 		module *types.Module
 
-		// @todo use these
-		supportedAggregationFunctions map[string]string
-		supportedFilterFunctions      map[string]bool
-
 		store *Store
 		rows  *sql.Rows
 
@@ -176,6 +172,19 @@ func (r *recordDatasource) Group(d report.GroupDefinition, name string) (bool, e
 
 		// - validate columns & functions
 		err = k.Def.Traverse(func(n *qlng.ASTNode) (bool, *qlng.ASTNode, error) {
+			if n.Ref == "count" && len(n.Args) == 0 {
+				pc := r.cols.FirstPrimary()
+				if pc == nil {
+					return false, nil, errors.New("cannot use count(): no primary key defined")
+				}
+				n.Args = append(n.Args, &qlng.ASTNode{
+					Ref: "distinct",
+					Args: qlng.ASTNodeSet{{
+						Symbol: pc.Name,
+					}},
+				})
+			}
+
 			if n.Symbol != "" {
 				if _, ok := auxLevelColumns[n.Symbol]; !ok {
 					return false, nil, fmt.Errorf("column %s does not exist on level %d", n.Symbol, r.nestLevel)
@@ -470,7 +479,6 @@ func (r *recordDatasource) baseQuery(f *report.Filter) (sqb squirrel.SelectBuild
 			Column(squirrel.Alias(squirrel.Expr(fmt.Sprintf(tcp, c.Name+".value")), c.Name))
 	}
 
-	// @todo this is temporary!!
 	sqb = squirrel.Select("*").
 		PlaceholderFormat(r.store.config.PlaceholderFormat).
 		FromSelect(sqb, "q_base")