宁波优化seo软件公司,兰州做网站优化,科技动态,上往建站在Oralce中实现select top N#xff1a;由于Oracle不支持select top 语句#xff0c;所以在oracle中经常是用order by 跟rownum的组合来实现select top n的查询。 方法1#xff1a;
SELECT *
FROM (SELECT * FROM EMP ORDER BY SAL DESC)
WHERE ROWNUM 5 --抽取处记录…在Oralce中实现select top N由于Oracle不支持select top 语句所以在oracle中经常是用order by 跟rownum的组合来实现select top n的查询。 方法1
SELECT *
FROM (SELECT * FROM EMP ORDER BY SAL DESC)
WHERE ROWNUM 5 --抽取处记录数方法2分组排序语法row_number() over(partition by 分组字段A,分组字段B,… order by 排序字段) RN_
SELECT *
FROM (SELECT A.EMPNO,
A.ENAME,
A.SAL,
ROW_NUMBER() OVER( /PARTITION BY EMPNO/ ORDER BY SAL DESC) AS RN_
FROM EMP A)
WHERE RN_ 5附取10-15条数据的方法 1、最接选择利用分析函数row_number() over(partition by 分组字段A,分组字段B,… order by 排序字段) RN_
SELECT *
FROM (SELECT A.EMPNO,
A.ENAME,
A.SAL,
ROW_NUMBER() OVER( /PARTITION BY EMPNO/ ORDER BY SAL DESC) AS RN_
FROM EMP A)
WHERE RN_ BETWEEN 10 AND 152、使用rownum虚列
SELECT *
FROM (SELECT A.EMPNO, A.ENAME, A.SAL, ROWNUM AS RN
FROM (SELECT A.EMPNO, A.ENAME, A.SAL FROM EMP A ORDER BY SAL DESC) A)
WHERE RN BETWEEN 10 AND 15;
