SQL使用ROW_NUMBER()OVER函数生成序列号
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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