row_number() over(PARTITION by 某某字段 order by 排序字段) as rn from table 例子: select * from ( select *, row_number() over(PARTITION by 某某字段 order by 排序字段) as rn from table )as t1 where t1.rn = 1
SELECT dense_rank()over(partition by road_id ORDER BY len) param,road_id from rs; -- count() over(partition by ... order by ...) SELECT count() over(partition by road_id) param,road_id from rs;
解释PARTITION BY在OVER()子句中的作用: PARTITION BY子句在OVER()子句内部使用,用于将结果集划分为多个分区。每个分区都独立地应用窗口函数。PARTITION BY后面跟着一个或多个列名,这些列的值相同的行将被分到同一个分区中。分区内的行可以进一步通过ORDER BY子句进行排序,但这对于first_value()等某些窗口函数来说不...
last_value 不能忽略 ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING first_value(取值字段) OVER ( PARTITION BY 分组字段 ORDER BY 排序字段 ) as firstInfo, last_value(取值字段) OVER ( PARTITION BY 分组字段 ORDER BY 排序字段 ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING ) as las...
PG row_num over partition by 构造数据 create table student(id serial,name character varying,course character varying,score integer); insert into student (name,course,score) values('周润发','语文',89); insert into student (name,course,score) values('周润发','数学',99);...
SELECT ROW_NUMBER() OVER (partition by discontinued_log.park_code ORDER BY discontinued_log.time desc) AS rownum, from discontinued_log ) as te where te.rownum <2 略微讲解: partition by discontinued_log.park_code discontinued_log.park_code这个是要分组的字段 ...
insert into tbl select ctid,user_name, tel, id_no from (select ctid , user_name, tel, id_no , row_number() over (partition by user_name, tel order by tel<>id_no ) as rn from user_info ) t where rn=1 on conflict (rowid) do nothing; insert into tbl select ctid,user_name,...
LEAD(sales_amount) OVER (PARTITION BY product_id ORDER BY year) as next_year_sales FROM sales; 在这个例子中,我们按product_id对数据进行分区,并在每个分区内按year排序。然后,我们使用LEAD函数来获取每个产品在同一年份的下一年的销售额。 注意事项: 当使用LEAD函数时,确保在查询中包含适当的ORDER BY子句...
select b.* into poi_hn_edit_clean_2 from ( select row_number() over (partition by hn_id order by hn_id) as repeat_number, * from poi_hn_edit_clean) b where b.repeat_number = 1 ; with subset as ( select row_number() over (partition by source_id order by id) as repeat_time...
WITH inactive_connections AS ( SELECT pid, rank() over (partition by client_addr order by backend_start ASC) as rank FROM pg_stat_activity WHERE pid <> pg_backend_pid( ) AND application_name !~ '(?:psql)|(?:pgAdmin.+)' AND datname = current_database() AND usename = current_user...