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经常遇到一种应用场景，将部分行的内容进行汇总、比较、排序。
比如数据表名称test.test2
select num,province from test.test2
得到结果：
1828;"黑龙江" 137;"黑龙江" 184;"黑龙江" 183;"福建" 125;"福建" 143;"福建" 119;"海南" 109;"海南" 132;"海南"
那么我希望将内容按照省份来排序，那么需要：
select province, num, sum(num) over (partition by province order by num desc ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) as all_num from test.test2
得到结果：
"海南";132;132 "海南";119;251 "海南";109;360 "福建";183;183 "福建";143;326 "福建";125;451 "黑龙江";1828;1828 "黑龙江";184;2012 "黑龙江";137;2149
如果还要看每行占整个省份的百分比，那么需要
with tmp as( select province, num, sum(num) over (partition by province order by num desc ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) as curr_num, sum(num) over (partition by province ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) as all_num from test.test2 ) select province, num, all_num, curr_num/all_num from tmp
结果如下
"海南";132;360;0.36666666666666666667 "海南";119;360;0.69722222222222222222 "海南";109;360;1.00000000000000000000 "福建";183;451;0.40576496674057649667 "福建";143;451;0.72283813747228381375 "福建";125;451;1.00000000000000000000 "黑龙江";1828;2149;0.85062819916240111680 "黑龙江";184;2149;0.93624941833410888785 "黑龙江";137;2149;1.00000000000000000000
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原文地址：http://www.cnblogs.com/liqiu/p/4273513.html
