feat(query): support GROUP BY GROUPING SETS clause.

[RinChanNOWWW]

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Summary

Basic implementation of GROUP BY GROUPING SETS.

Main idea:

Add a new PhysicalPlan: PhysicalPlan::AggregateExpand and its corresponding Transform: TransformExpandGroupingSets.

If the query is a GROUP BY GROUPING SETS clause, PhysicalPlan::AggregateExpand will be added to the front of PhysicalPlan::AggregatePartial. And the plan will be built into TransformExpandGroupingSets.

TransformExpandGroupingSets will expand the input DataBlock for each grouping set. It will fill NULLs if the group-by columns are not found in the grouping set.

Tacking in #10492

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1 Ignored Deployment

Name	Status	Preview	Comments	Updated
databend	⬜️ Ignored (Inspect)			Mar 15, 2023 at 4:42AM (UTC)

[sundy-li]

TransformExpandGroupingSets will expand the input DataBlock for each grouping set. It will fill NULLs if the group-by columns are not found in the grouping set.

What if the original column has nulls? Seem they share the same hashmap here.

[RinChanNOWWW]

What if the original column has nulls? Seem they share the same hashmap here.

There are the same when grouping.

We can distinguish this two kinds of NULLs by aggregate function grouping.

If grouping sets make it become NULL, grouping will return 1, else 0.

grouping will be implemented in later PR.

[sundy-li]

Rest Looks good to me.

[RinChanNOWWW]

cc @BohuTANG