一、row_number() over (partition by col1 order by col2) 二、 count(*) over (partition by col1) 三、 ceil(row_number:: double precision / 6) 四、stddev 五、avg(col1) over(partition by login_id, bucket_no) (二)group by 和 partition by的区别 (四)left outer join v.s. left jo...
count(1) OVER(PARTITION BY a ORDER BY a) AS count,是按a进行分组且组内按a进行升序,统计组内记录的条数。 row_number() OVER(PARTITION BY a ORDER BY a) AS rownum,是按a进行分组且组内按a进行升序,返回组内行编号。 __EOF__
count(1) OVER (PARTITION BY i."产品代码") AS rk_ct, sum(i."数量") OVER (PARTITION BY i."产品代码" ORDER BY i."日期" NULLS FIRST, i."数量") AS "入_递增" FROM (t_product_inventory i LEFT JOIN ( SELECT t_product_out."产品代码", sum(t_product_out."数量") AS "出_汇总"...
lag() over() 与 lead() over() 函数是跟偏移量相关的两个分析函数，通过这两个函数可以在一次查询...
ROW_NUMBER()OVER ( PARTITION BY COURSE ORDER BY SCORE) AS RN, COUNT(*) OVER (PARTITION BY COURSE) AS CNT FROM SCORES ), B AS (SELECT * FROM A WHERE RN>(CNT-0.5)/2 AND RN<(CNT+2.5)/2 ) SELECT COURSE, AVG(SCORE) AS SCORE FROM B ...
常用的聚合函数,例如 AVG、SUM、COUNT 等,也可以作为窗口函数使用。上文我们已经列举了一些聚合窗口函数的示例,再来看一个使用 AVG 函数计算移动平均值的例子: SELECTsaledate,amount,avg(amount)OVER(ORDERBYsaledateROWSBETWEEN1PRECEDINGAND1FOLLOWING)FROMsales_dataWHEREproduct='桔子'ANDchannel='淘宝';saledate|am...
postgres=# select * from (select ctid,sid,crt_time,mdf_time, count(*) over(partition by sid,crt_time) as cnt from tbl_dup) t where t.cnt>=2;ctid |sid|crt_time|mdf_time|cnt ---+---+---+---+--- (0,11)|511|2016-12-29 17:42:13.935348|2016-12-29 17:33:43.092625|2 (...
注意:可以不指定 PARTITION BY ,会将这个表当成一个“大窗口”。 窗口函数应用场景 应用场景: (1)用于分区排序 (2)动态Group By (3)Top N (4)累计计算 (5)层次查询 窗口函数的种类 窗口函数大体可以分为以下两种: 1、能够作为窗口函数的聚合函数(SUM、AVG、COUNT、MAX、MIN)。
function_name ([expression [, expression ... ]]) [ FILTER ( WHERE filter_clause ) ] OVER ( window_definition ) 其中window_definition语法如下: [ existing_window_name ] [ PARTITION BY expression [, ...] ] [ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS { FIRST | LAS...
注意:可以不指定 PARTITION BY ,会将这个表当成一个“大窗口”。 窗口函数应用场景 应用场景: (1)用于分区排序 (2)动态Group By (3)Top N (4)累计计算 (5)层次查询 窗口函数的种类 窗口函数大体可以分为以下两种: 1、能够作为窗口函数的聚合函数(SUM、AVG、COUNT、MAX、MIN)。