我正在寻找一种方法,为我在Postgres中所有的表找到行数。我知道我可以一次做一张表:
SELECT count(*) FROM table_name;
但我想看看所有表的行数,然后按它排序,以了解所有表的大小。
我正在寻找一种方法,为我在Postgres中所有的表找到行数。我知道我可以一次做一张表:
SELECT count(*) FROM table_name;
但我想看看所有表的行数,然后按它排序,以了解所有表的大小。
当前回答
简单的两步:(注意:不需要改变任何东西-只是复制粘贴) 1. 创建函数
create function
cnt_rows(schema text, tablename text) returns integer
as
$body$
declare
result integer;
query varchar;
begin
query := 'SELECT count(1) FROM ' || schema || '.' || tablename;
execute query into result;
return result;
end;
$body$
language plpgsql;
2. 运行此查询获取所有表的行数
select sum(cnt_rows) as total_no_of_rows from (select
cnt_rows(table_schema, table_name)
from information_schema.tables
where
table_schema not in ('pg_catalog', 'information_schema')
and table_type='BASE TABLE') as subq;
或 按表获取行数
select
table_schema,
table_name,
cnt_rows(table_schema, table_name)
from information_schema.tables
where
table_schema not in ('pg_catalog', 'information_schema')
and table_type='BASE TABLE'
order by 3 desc;
其他回答
我喜欢Daniel Vérité的回答。 但是当你不能使用CREATE语句时,你可以使用bash解决方案,如果你是windows用户,可以使用powershell解决方案:
# You don't need this if you have pgpass.conf
$env:PGPASSWORD = "userpass"
# Get table list
$tables = & 'C:\Program Files\PostgreSQL\9.4\bin\psql.exe' -U user -w -d dbname -At -c "select table_name from information_schema.tables where table_type='BASE TABLE' AND table_schema='schema1'"
foreach ($table in $tables) {
& 'C:\path_to_postresql\bin\psql.exe' -U root -w -d dbname -At -c "select '$table', count(*) from $table"
}
这里有一个更简单的方法。
tables="$(echo '\dt' | psql -U "${PGUSER}" | tail -n +4 | head -n-2 | tr -d ' ' | cut -d '|' -f2)"
for table in $tables; do
printf "%s: %s\n" "$table" "$(echo "SELECT COUNT(*) FROM $table;" | psql -U "${PGUSER}" | tail -n +3 | head -n-2 | tr -d ' ')"
done
输出应该如下所示
auth_group: 0
auth_group_permissions: 0
auth_permission: 36
auth_user: 2
auth_user_groups: 0
auth_user_user_permissions: 0
authtoken_token: 2
django_admin_log: 0
django_content_type: 9
django_migrations: 22
django_session: 0
mydata_table1: 9011
mydata_table2: 3499
你可以根据需要更新psql -U "${PGUSER}"部分来访问你的数据库
注意,head -n-2语法可能在macOS中不起作用,你可以使用不同的实现
在CentOS 7下的psql (PostgreSQL) 11.2上测试
如果你想按表排序,那就用sort来包装它
for table in $tables; do
printf "%s: %s\n" "$table" "$(echo "SELECT COUNT(*) FROM $table;" | psql -U "${PGUSER}" | tail -n +3 | head -n-2 | tr -d ' ')"
done | sort -k 2,2nr
输出;
mydata_table1: 9011
mydata_table2: 3499
auth_permission: 36
django_migrations: 22
django_content_type: 9
authtoken_token: 2
auth_user: 2
auth_group: 0
auth_group_permissions: 0
auth_user_groups: 0
auth_user_user_permissions: 0
django_admin_log: 0
django_session: 0
我通常不依赖于统计数据,尤其是在PostgreSQL中。
SELECT table_name, dsql2('select count(*) from '||table_name) as rownum
FROM information_schema.tables
WHERE table_type='BASE TABLE'
AND table_schema='livescreen'
ORDER BY 2 DESC;
CREATE OR REPLACE FUNCTION dsql2(i_text text)
RETURNS int AS
$BODY$
Declare
v_val int;
BEGIN
execute i_text into v_val;
return v_val;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
您可以使用此查询生成所有表名及其计数
select ' select '''|| tablename ||''', count(*) from ' || tablename ||'
union' from pg_tables where schemaname='public';
上述查询的结果将是
select 'dim_date', count(*) from dim_date union
select 'dim_store', count(*) from dim_store union
select 'dim_product', count(*) from dim_product union
select 'dim_employee', count(*) from dim_employee union
您需要删除最后一个联合符,并在末尾添加分号!!
select 'dim_date', count(*) from dim_date union
select 'dim_store', count(*) from dim_store union
select 'dim_product', count(*) from dim_product union
select 'dim_employee', count(*) from dim_employee **;**
跑! !
简单的两步:(注意:不需要改变任何东西-只是复制粘贴) 1. 创建函数
create function
cnt_rows(schema text, tablename text) returns integer
as
$body$
declare
result integer;
query varchar;
begin
query := 'SELECT count(1) FROM ' || schema || '.' || tablename;
execute query into result;
return result;
end;
$body$
language plpgsql;
2. 运行此查询获取所有表的行数
select sum(cnt_rows) as total_no_of_rows from (select
cnt_rows(table_schema, table_name)
from information_schema.tables
where
table_schema not in ('pg_catalog', 'information_schema')
and table_type='BASE TABLE') as subq;
或 按表获取行数
select
table_schema,
table_name,
cnt_rows(table_schema, table_name)
from information_schema.tables
where
table_schema not in ('pg_catalog', 'information_schema')
and table_type='BASE TABLE'
order by 3 desc;