postgresql 分组排序 partion

在postgresql8.4以后，postgresql添加了window函数。

像rank(),row_number(),partion等等，用法和slqserver一模一样。

SELECT *, ROW_NUMBER()   
        over   
        (PARTITION By task_id   
        order by ACTION_TIME ) as rowId 
		FROM CAMPAIGN_TASK_LOG where CAMPAIGN_TASK_LOG.AFTER_state in('10','15','21','22','23','24') 
		and ACTION_TYPE='surveysubmit'  

refurl:http://my.oschina.net/Kenyon/blog/79543