Function LookupOperName

src/backend/parser/parse_oper.c:100–137

* LookupOperName * Given a possibly-qualified operator name and exact input datatypes, * look up the operator. * * Pass oprleft = InvalidOid for a prefix op. * * If the operator name is not schema-qualified, it is sought in the current * namespace search path. * * If the operator is not found, we return InvalidOid if noError is true, * else raise an error. pstate and location are used

 * error position; pass NULL/-1 if not available.
 */
Oid
LookupOperName(ParseState *pstate, List *opername, Oid oprleft, Oid oprright,
			   bool noError, int location)
{
	Oid			result;

	result = OpernameGetOprid(opername, oprleft, oprright);
	if (OidIsValid(result))
		return result;

	/* we don't use op_error here because only an exact match is wanted */
	if (!noError)
	{
		char		oprkind;

		if (!OidIsValid(oprleft))
			oprkind = 'l';
		else if (OidIsValid(oprright))
			oprkind = 'b';
		else
		{
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("postfix operators are not supported"),
					 parser_errposition(pstate, location)));
			oprkind = 0;		/* keep compiler quiet */
		}

		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("operator does not exist: %s",
						op_signature_string(opername, oprkind,
											oprleft, oprright)),
				 parser_errposition(pstate, location)));
	}

	return InvalidOid;
}

/*
 * LookupOperWithArgs