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

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! !

其他回答

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

对于那些试图评估他们需要哪一个Heroku计划,又不能等待Heroku的慢行计数器刷新的人来说,一个简单实用的答案是:

基本上你想在psql中运行\dt,将结果复制到你最喜欢的文本编辑器中(它看起来像这样:

 public | auth_group                     | table | axrsosvelhutvw
 public | auth_group_permissions         | table | axrsosvelhutvw
 public | auth_permission                | table | axrsosvelhutvw
 public | auth_user                      | table | axrsosvelhutvw
 public | auth_user_groups               | table | axrsosvelhutvw
 public | auth_user_user_permissions     | table | axrsosvelhutvw
 public | background_task                | table | axrsosvelhutvw
 public | django_admin_log               | table | axrsosvelhutvw
 public | django_content_type            | table | axrsosvelhutvw
 public | django_migrations              | table | axrsosvelhutvw
 public | django_session                 | table | axrsosvelhutvw
 public | exercises_assignment           | table | axrsosvelhutvw

),然后运行regex搜索并替换,如下所示:

^[^|]*\|\s+([^|]*?)\s+\| table \|.*$

to:

select '\1', count(*) from \1 union/g

这将会给你一个非常类似的结果:

select 'auth_group', count(*) from auth_group union
select 'auth_group_permissions', count(*) from auth_group_permissions union
select 'auth_permission', count(*) from auth_permission union
select 'auth_user', count(*) from auth_user union
select 'auth_user_groups', count(*) from auth_user_groups union
select 'auth_user_user_permissions', count(*) from auth_user_user_permissions union
select 'background_task', count(*) from background_task union
select 'django_admin_log', count(*) from django_admin_log union
select 'django_content_type', count(*) from django_content_type union
select 'django_migrations', count(*) from django_migrations union
select 'django_session', count(*) from django_session
;

(您需要删除最后一个联合,并手动在末尾添加分号)

在psql中运行它,就完成了。

            ?column?            | count
--------------------------------+-------
 auth_group_permissions         |     0
 auth_user_user_permissions     |     0
 django_session                 |  1306
 django_content_type            |    17
 auth_user_groups               |   162
 django_admin_log               |  9106
 django_migrations              |    19
[..]

我不记得我收集这个的URL了。但希望这能帮助到你:

CREATE TYPE table_count AS (table_name TEXT, num_rows INTEGER); 

CREATE OR REPLACE FUNCTION count_em_all () RETURNS SETOF table_count  AS '
DECLARE 
    the_count RECORD; 
    t_name RECORD; 
    r table_count%ROWTYPE; 

BEGIN
    FOR t_name IN 
        SELECT 
            c.relname
        FROM
            pg_catalog.pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
        WHERE 
            c.relkind = ''r''
            AND n.nspname = ''public'' 
        ORDER BY 1 
        LOOP
            FOR the_count IN EXECUTE ''SELECT COUNT(*) AS "count" FROM '' || t_name.relname 
            LOOP 
            END LOOP; 

            r.table_name := t_name.relname; 
            r.num_rows := the_count.count; 
            RETURN NEXT r; 
        END LOOP; 
        RETURN; 
END;
' LANGUAGE plpgsql; 

执行select count_em_all();应该得到所有表的行数。

摘自我在GregSmith的回答中的评论,使其更具可读性:

with tbl as (
  SELECT table_schema,table_name 
  FROM information_schema.tables
  WHERE table_name not like 'pg_%' AND table_schema IN ('public')
)
SELECT 
  table_schema, 
  table_name, 
  (xpath('/row/c/text()', 
    query_to_xml(format('select count(*) AS c from %I.%I', table_schema, table_name), 
    false, 
    true, 
    '')))[1]::text::int AS rows_n 
FROM tbl ORDER BY 3 DESC;

感谢@ a_horis_with_no_name

下面的查询将给出每个表的行数和大小

选择table_schema, table_name, pg_relation_size('“' | | table_schema | |”“。”“| | table_name | |”“”)/ 1024/1024 size_MB, (xpath('/row/c/text()', query_to_xml(format('select count(*) AS c from %I.)%I', table_schema, table_name), false, true, ")))[1]::text::int AS rows_n 从information_schema.tables order by size_MB