www.fltk.net > Mysql数据库中多条重复数据,如何只删除一条?

Mysql数据库中多条重复数据,如何只删除一条?

列出要保留的记录ID,可以把这个结果写到一个临时表t1中: SELECT MAX(id) AS max_id FROM pedigree GROUP BY number 然后:DELETE FROM pedigree WHERE id NOT IN (SELECT id FROM t1) 也就是:delete from pedigree where id not in(select * ...

delete from shop_sell_logs where log_id >=200 and log_id=200 and log_id

-- 保留相同A值的最小id行 select * from table_a a where not exists ( select 1 from table_a b where b.A = a.A and b.id < a.id )

select * from table ###where not exists (select * from table ###where # = #and ## < ##) 在使用mysql时,有时需要查询出某个字段不重复的记录,虽然mysql提供 有distinct这个关键字来过滤掉多余的重复记录只保留一条,但往往只用它来返回不...

表名 table_name 要操作的字段名 field_name 如果删除字段的值,可以将所有值清空: UPDATE table_name SET field_name = ''; 如果删除字段(这个字段从此就没有了): ALTER TABLE table_name DROP COLUMN field_name;

delete from 表名 where id in (1,3,5)

-- 保留相同A值的最小id行 select * from table_a a where not exists ( select 1 from table_a b where b.A = a.A and b.id < a.id )

inner join 会兼顾两张表,应该是你另一个表里面那个主键的数据有两条;;;先确定主表,用left join 或者right join 就会只有一条了

delete from `mygame_article` where title in (select title from `mygame_article` group by id having count(title) > 1) and id not in (select max(id) from `mygame_article` group by title having count(title) > 1); 随手写了个,前半...

大侠,group by 一下不就行了, select * from question group by question_type

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