Function scanNameSpaceForCTE

src/backend/parser/parse_relation.c:267–291

* Search the query's CTE namespace for a CTE matching the given unqualified * refname. Return the CTE (and its levelsup count) if a match, or NULL * if no match. We need not worry about multiple matches, since parse_cte.c * rejects WITH lists containing duplicate CTE names. */

 * rejects WITH lists containing duplicate CTE names.
 */
CommonTableExpr *
scanNameSpaceForCTE(ParseState *pstate, const char *refname,
					Index *ctelevelsup)
{
	Index		levelsup;

	for (levelsup = 0;
		 pstate != NULL;
		 pstate = pstate->parentParseState, levelsup++)
	{
		ListCell   *lc;

		foreach(lc, pstate->p_ctenamespace)
		{
			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);

			if (strcmp(cte->ctename, refname) == 0)
			{
				*ctelevelsup = levelsup;
				return cte;
			}
		}
	}
	return NULL;
}

/*
 * Search for a possible "future CTE", that is one that is not yet in scope