SQL> set linesize 200 SQL> select * from (select a.* ,row_number() over( order by empno) rn from emp a) where rn=1 2 3 ; EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO DNAME RN ---------- ---------- --------- ---
SELECT * FROM tab_init WHERE id IN ( --根据Data分类获取数据最小ID列表 select max(id) from tab_init group by a,b ) 先找出重复数据的 最大的Id ( group by 后面可跟多列, 根据规则找到重复数据), 取出 id 最大或最小的 Id, 然后使用 in查询,就可以得到不重复的数据
select * from table_a where id in (select min(id) from table_a group by a) )) SUBSTRING_INDEX(cids,',',1))截取字符串 group by 按照什么分组 select min(id) from table_a group by a 根据a来分组找出最小的id
select s.* from ( select *, row_number() over (partition by PersonnelAccount order BY PersonnelID) as group_idx from AUX_SpecialPersonnel ) swhere s.group_idx > 1
delete from test where id not in ( select a.id from (select min(id) as id from test group by form_id ) as a ) 一百天记录 SELECT *FROM table_name where date_sub(curdate(), INTERVAL 100 DAY)>=date(FROM_UNIXTIME(add_time))
背景: A表.B表两表关联,关联出来的结果里B表有不止一条,需求是只要B表结果中的某一条(按某字段排序) 首先想到了直接写个带排序的子查询去匹配外围的值,从这个结果集中只要第一条,但是经过验证发现,里边的条件是获取不到外层的值的,因此此方案不可行. 经过百度,发现 row_number() over函数可用,以下是数据环境及结果. 创建数据环境 )); insert into A values('alan'); insert into A values('Alee'); insert into
查询 text 表中,user_name字段值重复的数据及重复次数 select user_name,count(*) as count from text 删除 text 表中,重复出现的数据只保留 ID 最大的一条数据,没有重复的数据不删除. AND id not in( select id from (select max(id) as id,count(user_name) as count from text order by count desc) as tab) AND id no
如何用SQL排除重复结果只取字段最大值的记录?要求得到的结果(即是PID相同的记录只取ID值最大的那一条). select * from [Sheet1$] a from [Sheet1$] where PID=a.PID and ID>a.ID) select a.* from [Sheet1$] a inner join (select PID,max(ID) as max_id from [Sheet1$] group by PID) b on a.PID=b.PID and a.ID=b
删除表中重复数据,留下ID比较小的行 delete from 表 where [重复字段] in (select [重复字段] from 表 group by 字段 having count([字段]) > 1) and ID not in (select min(ID) from [表] group by [字段] having count([字段])> 1)
