oracle ROW_NUMBER() OVER

row_number() OVER (PARTITION BY COL1 ORDER BY COL2) 

表示根据COL1分组，在分组内部根据COL2排序，而此函数计算的值就表示每组内部排序后的顺序编号

select departmentid,workcode
       ,ROW_NUMBER() OVER (partition by departmentid ORDER BY workcode asc) line
from hrmresource

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