QUERY PLAN
Aggregate (cost=66.14..66.15 rows=1 width=8)
-> Sort (cost=65.63..65.71 rows=34 width=231)
Sort Key: s.status, u.pinyin_shortcut, s.target_completed_at, s.updated_at DESC
-> HashAggregate (cost=64.42..64.76 rows=34 width=231)
Group Key: s.id, u.id
-> Hash Left Join (cost=18.24..64.25 rows=34 width=29)
Hash Cond: (s.head_of = u.id)
-> Seq Scan on tbl_tasks s (cost=0.00..45.92 rows=34 width=34)
Filter: ((parent_id IS NULL) AND (task_group_id = 106))
-> Hash (cost=16.44..16.44 rows=144 width=7)
-> Seq Scan on tbl_users u (cost=0.00..16.44 rows=144 width=7)