EXPLAIN SELECT MAX(cnt) FROM (SELECT count(*) as cnt FROM LINEITEM group by L_SUPPKEY);
┌─explain───────────────────────────────────────────────┐
│ Expression (Projection)                               │
│   Expression (Before ORDER BY and SELECT)             │
│     Aggregating                                       │
│       Expression (Before GROUP BY)                    │
│         Expression (Projection)                       │
│           Expression (Before ORDER BY and SELECT)     │
│             Aggregating                               │
│               Expression (Before GROUP BY)            │
│                 ReadFromStorage (Read from MergeTree) │
└───────────────────────────────────────────────────────┘