统计mysql和pgsql库和表占用大小方式

use information_schema;
select table_schema,round(sum(data_length/1024/1024),2) as data from tables group by table_schema order by data desc;

use information_schema;
select table_name,round(sum(data_length/1024/1024),2) as data from tables where table_schema='db_name' group by table_name order by data desc;

SELECT 
    nspname AS table_schema,
    ROUND(SUM(pg_total_relation_size(c.oid)) / 1024.0 / 1024.0, 2) AS total_mb
FROM 
    pg_class c
JOIN 
    pg_namespace n ON c.relnamespace = n.oid
WHERE 
    c.relkind = 'r'
GROUP BY 
    nspname
ORDER BY 
    total_mb DESC;

SELECT 
    relname AS table_name,
    ROUND(pg_relation_size(c.oid) / 1024.0 / 1024.0, 2) AS data_mb  -- 表数据大小（MB）
FROM 
    pg_class c
JOIN 
    pg_namespace n ON c.relnamespace = n.oid
WHERE 
    n.nspname = 'schema_name'  -- 指定schema名称
    AND c.relkind = 'r'  -- 只统计普通表
ORDER BY 
    data_mb DESC;