[ORACLE] 分組依序編號：row_number()

Base Data:
    DEPTNO ENAME
---------- ----------
        A ASMITH
        A BALLEN
        A CWARD
        B DJONES
        B EMARTIN
        C FBLAKE
        C GCLARK
        C HSCOTT


↓↓↓↓  想要分組有編號


    DEPTNO ENAME SEQ
---------- ------  ----
        A ASMITH 1
        A BALLEN 2
        A CWARD 3
        B DJONES 1
        B EMARTIN 2
        C FBLAKE 1
        C GCLARK 2
        C HSCOTT 3


SELECT DEPTNO, ENAME,row_number() over(partition by DEPTNO ORDER BY ENAME)SEQ FROM XXX

partition by DEPTNO←←依DEPTNO分組

如果沒要分組可省略partition by