Question

我有一个游戏，在数据库中我按日期和时间保存用户操作。时间。

CREATE TABLE user_actions
(
    aId BIGSERIAL PRIMARY KEY NOT NULL,
    userId BIGINT NOT NULL REFERENCES users(uId) DEFERRABLE INITIALLY DEFERRED,
    aDate TIMESTAMP without time zone DEFAULT now(),
    aType INTEGER NOT NULL DEFAULT 0
);

我的用户通过电子邮件识别

CREATE TABLE users(
   uId BIGSERIAL PRIMARY KEY NOT NULL,
   uName VARCHAR (50) NOT NULL,
   uEmail VARCHAR (75) UNIQUE  NULL
);

每天新增奖品每天都有不同数量的奖品

CREATE TABLE prizes(
   pId BIGSERIAL PRIMARY KEY NOT NULL,
   pDate TIMESTAMP without time zone DEFAULT now(),
   pType INTEGER NULL
   pSize INTEGER NULL
);

此查询列出了userId及其每个用户的上一个操作日期

select distinct userId, max(aDate) from user_actions GROUP BY userId order by userId;

我想创建一个查询，该查询将计算自每个用户上次操作以来添加的奖品数量。

我正在跑步：

操作系统：Debian
DB：Postgresql
代码：Django

Answer 1

我想我会使用CTE虽然尚未经过测试

WITH last_actions AS (
SELECT DISTINCT userId, MAX(aDate) as last_logged 
 FROM user_actions 
 GROUP BY userId ORDER BY userId)

SELECT a.userId, COUNT(b.pDate) 
 FROM last_actions a, prizes b 
 WHERE b.pDate >= a.last_logged      
 GROUP BY a.userId;

复杂的SQL语法

1 个答案: