| Aggregate [a#0, spark_grouping_id#0L], [a#0, max(a#0) AS max(a)#0, count(a#0) AS count(a)#0L] | |
| +- Expand [[id#0L, a#0, b#0, a#0, 0], [id#0L, a#0, b#0, null, 1]], [id#0L, a#0, b#0, a#0, spark_grouping_id#0L] | |
| +- Project [id#0L, a#0, b#0, a#0 AS a#0] | |
| +- LocalRelation <empty>, [id#0L, a#0, b#0] |