PostgreSQL查询以选择上周的数据？ [英] PostgreSQL Query to select data from last week?

问题描述

我有一张桌子，上面有我所有顾客的购买物。我想选择上周（从星期日开始的一周）中的所有条目。

I have a table which has all the purchases of my costumers. I want to select all entries from the last week, (week start from Sunday).

id    value  date
5907  1.20   "2015-06-05 09:08:34-03"
5908  120.00 "2015-06-09 07:58:12-03"

我已经尝试过：

SELECT id, valor, created, FROM compras WHERE created >= now() - interval '1 week' and parceiro_id= '1' 

但是我获得了上周的数据，包括本周的数据，我只想要上周的数据。

But I got the data from the last week including data from this week, I only want data from the last week.

如何仅从上周获得数据？

How to get data only from last week ?

推荐答案

此条件将返回上周日至周六的记录：

This condition will return records from Sunday till Saturday last week:

WHERE created BETWEEN
    NOW()::DATE-EXTRACT(DOW FROM NOW())::INTEGER-7 
    AND NOW()::DATE-EXTRACT(DOW from NOW())::INTEGER

有一个例子：

WITH compras AS (
    SELECT ( NOW() + (s::TEXT || ' day')::INTERVAL )::TIMESTAMP(0) AS created
    FROM generate_series(-20, 20, 1) AS s
)
SELECT to_char( created, 'DY'::TEXT), created
FROM compras
WHERE created BETWEEN
    NOW()::DATE-EXTRACT(DOW FROM NOW())::INTEGER-7 
    AND NOW()::DATE-EXTRACT(DOW from NOW())::INTEGER

@ d456：

不使用 BETWEEN 包括午夜

那右边， BETWEEN 包括午夜在间隔的两端的星期日。要在间隔结束时排除周日的午夜，必须使用运算符> = 和< ：

That right, BETWEEN includes midnight on Sunday at both ends of the interval. To exclude midnight on Sunday at end of interval it is necessary to use operators >= and <:

WITH compras AS (
    SELECT s as created
    FROM generate_series( -- this would produce timestamps with 20 minutes step
             (now() - '20 days'::interval)::date,
             (now() + '20 days'::interval)::date,
             '20 minutes'::interval) AS s
)
SELECT to_char( created, 'DY'::TEXT), created
FROM compras
WHERE TRUE
    AND created >= NOW()::DATE-EXTRACT(DOW FROM NOW())::INTEGER-7
    AND created <  NOW()::DATE-EXTRACT(DOW from NOW())::INTEGER

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