Deveel.Data.Sql.Query.QueryPlanner.PlanGroup C# (CSharp) Method

        private IQueryPlanNode PlanGroup(IQueryPlanNode node, GroupInfo groupInfo)
        {
            // If there is more than 1 aggregate function or there is a group by
            // clause, then we must add a grouping plan.
            if (groupInfo.Columns.AggregateCount > 0 ||
                groupInfo.GroupByCount > 0) {
                // If there is no GROUP BY clause then assume the entire result is the
                // group.
                if (groupInfo.GroupByCount == 0) {
                    node = new GroupNode(node, groupInfo.GroupMax, groupInfo.FunctionExpressions, groupInfo.FunctionNames);
                } else {
                    // Do we have any group by functions that need to be planned first?
                    int gfsz = groupInfo.GroupByExpressions.Length;
                    if (gfsz > 0) {
                        var groupFunList = new SqlExpression[gfsz];
                        var groupFunName = new string[gfsz];
                        for (int i = 0; i < gfsz; ++i) {
                            groupFunList[i] = groupInfo.GroupByExpressions[i];
                            groupFunName[i] = "#GROUPBY-" + i;
                        }

                        node = new CreateFunctionsNode(node, groupFunList, groupFunName);
                    }

                    // Otherwise we provide the 'group_by_list' argument
                    node = new GroupNode(node, groupInfo.GroupByNames, groupInfo.GroupMax, groupInfo.FunctionExpressions, groupInfo.FunctionNames);
                }
            } else {
                // Otherwise no grouping is occurring.  We simply need create a function
                // node with any functions defined in the SELECT.
                // Plan a FunctionsNode with the functions defined in the SELECT.
                if (groupInfo.FunctionCount > 0)
                    node = new CreateFunctionsNode(node, groupInfo.FunctionExpressions, groupInfo.FunctionNames);
            }

            return node;
        }