首页 > 代码库 > SQL

SQL


删除重复数据 :

DELETE FROM country_code 
WHERE
    country_code NOT IN (SELECT 
        *
    FROM
        (select max(country_code) from country_code group by country_name )as tmp
    );

根据一个表的数据,更新另一个表的数据 

UPDATE event_insert as a,country_code as b
SET 
    a.country_code = b.country_code
WHERE
    a.event_country_zh = b.country_name;

 

SQL