n option named character classes, regular expressions names, regions natural joins NEG (negative) transition types negative (NEG) transition types nested group operations nested tables NEW_TIME function NEXT_DAY function NOCYCLE keyword nodes CONNECT_BY_ROOT operator existsNode( ) member hierarchical queries leaf, identifying paths, finding root 2nd non-equi-joins 2nd self nonaggregate expressions, GROUP BY clause nonaggregate functions, GROUP BY clause noncorrelated subqueries WITH clause nonprocedural languages NOT BETWEEN operator NOT IN operator multiple-row subqueries NOT operator pattern-matching and WHERE clause notation, path elements NTILE analytic function NULL expression NULL values aggregate functions analytic ranking functions cells, missing compound queries GROUP BY clause NVL function compared to GROUPING function testing for NULLIF function numbers, converting to dates numeric amounts, printing NUMTODSINTERVAL function NUMTOYMINTERVAL function NVL function averages NULL values, compared to GROUPING function syntax 2nd NVL2 function, syntax 2nd