SELECT 
    COUNT(*)
FROM
    table_name;

SELECT 
    'tablename1' tablename, 
     COUNT(*) rows
FROM
    table_name1
UNION 
SELECT 
    'tablename2' tablename, 
     COUNT(*) rows
FROM
    table_name2;

3.獲取某個資料庫的所有表的行數（information_schema 方法有時候不準確）

use information_schema;

select table_name,table_rows from tables 
where TABLE_SCHEMA = 'db.name' 
order by table_rows desc;