postgresql取第一行数据_postgresql-从表中随机获取一条记录

postgresql如何从表中高效的随机获取一条记录

select C_BH from db_scld.t_scld_cprscjl order by `random()` LIMIT 1;

select c_jdrybm from db_scld.t_jdry

where c_bmbm = v_scdd and c_sfyx ='1' and c_ryzszt not in ('05','12','11','07','09','13') order by `random()` limit 1

db_jdsjpt=# explain analyze select C_BH from db_scld.t_scld_cprscjl order by random() LIMIT 1;

QUERY PLAN

---------------------------------------------------------------------------------------------------

Limit (cost=61029.94..61029.94 rows=1 width=41) (actual time=587.193..587.193 rows=1 loops=1)

-> Sort (cost=61029.94..63172.22 rows=856911 width=41) (actual time=587.185..587.185 rows=1 loops=1)

Sort Key: (random())

Sort Method: top-N heapsort Memory: 25kB

-> Seq Scan on