generating XML documents global indexes global inline views greater than (>) operator greater than or equal to (>=) operator GREATEST function greediness (regular expressions) GROUP BY clause 2nd 3rd 4th composite columns concatenated groupings CUBE keyword errors filters and GROUPING SETS keyword partial CUBE partial rollups repeating column names ROLLUP keyword UNION operations group operations aggregate functions ALL keyword DISTINCT keyword NULLs EXPLAIN PLANs GROUP BY clause 2nd composite columns concatenated groupings CUBE keyword NULL values partial CUBE partial rollups repeating column names ROLLUP keyword WHERE clause GROUP_ID function GROUPING function GROUPING SETS concatenated groupings ROLLUP and CUBE as arguments GROUPING_ID function 2nd HAVING clause nested summary information, GROUPING SETS keyword UNION query GROUP_ID function overview grouping columns, concatenation scalar functions XMLAgg( ) function GROUPING function ordering GROUPING SETS keyword concatenated groupings ROLLUP and CUBE as arguments GROUPING_ID function ordering overview