语法:row_number() over(partition by column order by column)
简单的说
row_number()
从1开始,为每一条分组记录返回一个数字,这里的row_number() over (order by cylh desc)
是先把xlh列降序,再为降序以后的每条cylh记录返回一个序号。
示例:
分析: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(组内连续的唯一的)
也可这样使用:row_number() over (order by col2)
例子:
建立测试表,并插入测试数据
create table test_row_number_01( cmzh varchar(10) not null, cylh varchar(10) null, mje money null, );
insert into test_row_number_01(cmzh,cylh,mje) values (2106000011,20281997,10.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000010,20281996,10.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000008,20281995,0.00) insert into test_row_number_01(cmzh,cylh,mje) values(2106000006,20281994,9.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000004,20281993,5.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000001,20281992,10.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000002,20281992,10.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000007,20217280,0.00) insert into test_row_number_01(cmzh,cylh,mje) values(2106000009,20172458,5.50) insert into test_row_number_01(cmzh,cylh,mje) values(2106000005,20121813,0.00)
执行脚本自动生成行号并按cylh进行排序(滑动查看代码)
select row_number()over(order by cylh desc) as rownum,* from test_row_number_01
结果如下:
注意:在使用over
等开窗函数时,over
里头的分组及排序的执行晚于“where
,group by
,order by
”的执行。
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