Gordon Linoff
2020-12-22 20:06:02
Impala introduced the group by modifiers in 7.2.2:
Added support for GROUP BY ROLLUP, CUBE and GROUPING SETS. The GROUP BY ROLLUP clause creates a group for each combination of column expressions. The CUBE clause creates groups for all possible combinations of columns. The GROUPING SETS just lets you list out the combinations of expressions that you want to GROUP BY.
This is explained in the documentation for GROUP BY starting with that version.