QUERY PLAN
Aggregate (cost=8.19..8.20 rows=1 width=8)
-> Sort (cost=8.17..8.18 rows=1 width=370)
Sort Key: tbl_ledger_auxiliary_items.is_delete, tbl_ledger_auxiliary_items.sort, tbl_ledger_auxiliary_items.id
-> Index Scan using idx_tbl_ledger_auxiliary_items_ledger_serial_no on tbl_ledger_auxiliary_items (cost=0.14..8.16 rows=1 width=370)
Index Cond: ((ledger_id = 1) AND (type = '1'::smallint))