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
不确定bash中的答案对您来说是否可以接受,但FWIW…
PGCOMMAND=" psql -h localhost -U fred -d mydb -At -c \"
SELECT table_name
FROM information_schema.tables
WHERE table_type='BASE TABLE'
AND table_schema='public'
\""
TABLENAMES=$(export PGPASSWORD=test; eval "$PGCOMMAND")
for TABLENAME in $TABLENAMES; do
PGCOMMAND=" psql -h localhost -U fred -d mydb -At -c \"
SELECT '$TABLENAME',
count(*)
FROM $TABLENAME
\""
eval "$PGCOMMAND"
done
其他回答
这对我很有效
SELECT schemaname,relname,n_live_tup FROM pg_stat_user_tables ORDER BY n_live_tup DESC;
如果您在psql shell中,使用\gexec允许您执行syed的答案和Aur的答案中描述的语法,而无需在外部文本编辑器中手动编辑。
with x (y) as (
select
'select count(*), '''||
tablename||
''' as "tablename" from '||
tablename||' '
from pg_tables
where schemaname='public'
)
select
string_agg(y,' union all '||chr(10)) || ' order by tablename'
from x \gexec
注意,string_agg()既用于分隔所有语句之间的联合,也用于将分隔的数据箭头粉碎为一个单元,以便传递到缓冲区。
\ gexec 将当前查询缓冲区发送到服务器,然后将查询输出的每一行的每一列(如果有的话)视为要执行的SQL语句。
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;
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;
不确定bash中的答案对您来说是否可以接受,但FWIW…
PGCOMMAND=" psql -h localhost -U fred -d mydb -At -c \"
SELECT table_name
FROM information_schema.tables
WHERE table_type='BASE TABLE'
AND table_schema='public'
\""
TABLENAMES=$(export PGPASSWORD=test; eval "$PGCOMMAND")
for TABLENAME in $TABLENAMES; do
PGCOMMAND=" psql -h localhost -U fred -d mydb -At -c \"
SELECT '$TABLENAME',
count(*)
FROM $TABLENAME
\""
eval "$PGCOMMAND"
done