QUERY PLAN
Group (cost=2704.48..2706.53 rows=163 width=4)
Group Key: out_device
-> Sort (cost=2704.48..2705.51 rows=410 width=4)
Sort Key: out_device
-> Seq Scan on tbl_punch (cost=0.00..2686.69 rows=410 width=4)
Filter: ((out_device IS NOT NULL) AND (user_id = 1001))