oracle的 listagg() WITHIN GROUP () 函数使用
- 使用条件:数据统计行转列
– 查询部门为20的员工列表【显然是多列显示】
SELECT t.DEPTNO,t.ENAME FROM SCOTT.EMP t where t.DEPTNO = ‘20’ ; - 使用 listagg() WITHIN GROUP () 将多行合并成一行并以字符分割
SELECT
T .DEPTNO,
listagg (T .ENAME, ',') WITHIN GROUP (ORDER BY T .ENAME) names
FROM
SCOTT.EMP T
WHERE
T .DEPTNO = '20'
GROUP BY
T .DEPTNO
查询效果:
- 使用 listagg() within GROUP () over 将多行记录在一行显示(很少遇到过这种使用场景)
SELECT
T .DEPTNO,
listagg (T .ENAME, ',') WITHIN GROUP (ORDER BY T .ENAME) over(PARTITION BY T .DEPTNO)
FROM
SCOTT.EMP T
WHERE
T .DEPTNO = '20'
mysql相同效果的实现
https://blog.youkuaiyun.com/sinat_36257389/article/details/95052001
PostgreSQL 相同效果的实现
https://blog.youkuaiyun.com/sinat_36257389/article/details/95611686