sql – 为具有分组的视图生成id行

create or replace view daily_transactions as
select 
    generate_series(1,count(t)) as id,t.ic,t.bio_id,t.wp,date_trunc('day',t.transaction_time)::date transaction_date,min(t.transaction_time)::time time_in,w.start_time wp_start,w.start_time - min(t.transaction_time)::time in_diff,max(t.transaction_time)::time time_out,w.end_time wp_end,max(t.transaction_time)::time - w.end_time out_diff,count(t) total_transactions,calc_att_status(date_trunc('day',t.transaction_time)::date,min(t.transaction_time)::time,max(t.transaction_time)::time,w.start_time,w.end_time ) status        
from transactions t
left join wp w  on (t.wp = w.wp_name)
group by ic,bio_id,transaction_time),w.end_time;

我最终得到了重复的行. SELECT DISTINCT也不起作用.有任何想法吗？

交易表：

create table transactions(
    id serial primary key,ic text references users(ic),wp text references wp(wp_name),serial_no integer,bio_id integer,node integer,finger integer,transaction_time timestamp,transaction_type text,transaction_status text        
 );

WP表：

create table wp(
    id serial unique,wp_name text primary key,start_time time,end_time time,description text,status text    
);

查看输出：

解决方法

CREATE OR REPLACE VIEW daily_transactions as
SELECT row_number() OVER () AS id,t.transaction_time::date AS transaction_date,min(t.transaction_time)::time AS time_in,w.start_time AS wp_start,w.start_time - min(t.transaction_time)::time AS in_diff,max(t.transaction_time)::time AS time_out,w.end_time AS wp_end,max(t.transaction_time)::time - w.end_time AS out_diff,count(*) AS total_transactions,calc_att_status(t.transaction_time::date,w.end_time) AS status
FROM   transactions t
LEFT   JOIN wp w ON t.wp = w.wp_name
GROUP  BY t.ic,t.transaction_time::date,w.end_time;

主要观点

> generate_series()在聚合函数之后应用,但会生成多行,从而将所有输出行相乘.
window function row_number()也在聚合函数之后应用,但每行只生成一个数字.你需要PostgreSQL 8.4或更高版本.

> date_trunc()在date_trunc(‘day’,t.transaction_time):: date中是多余的.
t.transaction_time :: date实现相同,简单和简单快点.
>使用count(*)代替count(t).这里的结果相同,但速度要快一些.

其他一些细微的变化.

（编辑：李大同）

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