Function ExecTypeFromTLInternal

src/backend/executor/execTuples.c:1972–2005

}

static TupleDesc
ExecTypeFromTLInternal(List *targetList, bool skipjunk)
{
	TupleDesc	typeInfo;
	ListCell   *l;
	int			len;
	int			cur_resno = 1;

	if (skipjunk)
		len = ExecCleanTargetListLength(targetList);
	else
		len = ExecTargetListLength(targetList);
	typeInfo = CreateTemplateTupleDesc(len);

	foreach(l, targetList)
	{
		TargetEntry *tle = lfirst(l);

		if (skipjunk && tle->resjunk)
			continue;
		TupleDescInitEntry(typeInfo,
						   cur_resno,
						   tle->resname,
						   exprType((Node *) tle->expr),
						   exprTypmod((Node *) tle->expr),
						   0);
		TupleDescInitEntryCollation(typeInfo,
									cur_resno,
									exprCollation((Node *) tle->expr));
		cur_resno++;
	}

	return typeInfo;
}

/*
 * ExecTypeFromExprList - build a tuple descriptor from a list of Exprs