Function project_aggregates

src/backend/executor/nodeAgg.c:1422–1442

* Project the result of a group (whose aggs have already been calculated by * finalize_aggregates). Returns the result slot, or NULL if no row is * projected (suppressed by qual). */

 * projected (suppressed by qual).
 */
static TupleTableSlot *
project_aggregates(AggState *aggstate)
{
	ExprContext *econtext = aggstate->ss.ps.ps_ExprContext;

	/*
	 * Check the qual (HAVING clause); if the group does not match, ignore it.
	 */
	if (ExecQual(aggstate->ss.ps.qual, econtext))
	{
		/*
		 * Form and return projection tuple using the aggregate results and
		 * the representative input tuple.
		 */
		return ExecProject(aggstate->ss.ps.ps_ProjInfo);
	}
	else
		InstrCountFiltered1(aggstate, 1);

	return NULL;
}

/*
 * Find input-tuple columns that are needed, dividing them into