文章目录
文档用途
我们知道oracle里有一个系统表存的rownum。本文旨在介绍在HG数据库中简单方便的获取所有表的条数的方法。
详细信息
通过如下sql:
sql
select relname as 表名, reltuples as 条数 from pg_class where relkind = 'r' and relnamespace = (select oid from pg_namespace where nspname='highgo') order by 条数 desc;
效果如下:
sql
highgo=# select relname as 表名, reltuples as 条数 from pg_class where relkind = 'r' and relnamespace = (select oid from pg_namespace where nspname='highgo') order by 条数 desc;
表名 | 条数
-------------+--------
t1 | 0
aaa | 0
b | 0
test1 | 0
t | 0
d1 | 0
d2 | 0
product | 0
addressbook | 5
(9 rows)
在很多情况下这个值是一个参考值,想更新此值可以通过如下命令:
sql
highgo=# select * from t1;
a | b
---+---
3 | a
(1 row)
highgo=# analyze t1;
ANALYZE
效果如下:
sql
highgo=# select relname as 表名, reltuples as 条数 from pg_class where relkind = 'r' and relnamespace = (select oid from pg_namespace where nspname='highgo') order by 条数 desc;
表名 | 条数
-------------+--------
t1 | 1
aaa | 0
b | 0
test1 | 0
t | 0
d1 | 0
d2 | 0
product | 0
addressbook | 5
(9 rows)