具有多列和工作日的 PostgreSQL 交叉表查询答案

【问题标题】：PostgreSQL crosstab query with multiple columns and week day具有多列和工作日的 PostgreSQL 交叉表查询
【发布时间】：2018-09-26 18:53:31
【问题描述】：

我正在尝试通过对几列进行分组来创建一个数据透视表：用户 ID、姓名、周数和当天的名称。当前请求没有给出期望的结果。我需要帮助。

这是我的桌子：

user_id name    week_number day_name    price
2       Luc     8           Sunday      10
2       Luc     8           Monday      15
2       Luc     8           Tuesday     8
2       Luc     8           Wednesday   2
2       Luc     8           Thursday    9
2       Luc     8           Friday      9
2       Luc     8           Saturday    11
2       Luc     9           Saturday    1
2       Luc     9           Friday      13
3       Mathieu 8           Sunday      22
3       Mathieu 8           Monday      13
3       Mathieu 8           Tuesday     9
3       Mathieu 8           Wednesday   3

这是我目前的要求：

SELECT *
FROM   crosstab(
'SELECT user_id, name, week_number,day_name,price
FROM   table_1
ORDER  BY 1,2,3,4' 
) AS ct (
"user_id" integer,
"day_name" text,
"Sunday" integer,   
"Monday" integer,   
"Tuesday" integer,  
"Wednesday" integer,    
"Thursday" integer, 
"Friday" integer,   
"Saturday" integer
);

这是我想要得到的结果。

【问题讨论】：

标签： postgresql pivot grouping pivot-table crosstab

【解决方案1】：

你可以只使用条件聚合：

SELECT user_id, name, week_number
       MAX(price) FILTER (WHERE day_name = 'Sunday') as Sunday,
       MAX(price) FILTER (WHERE day_name = 'Monday') as Monday,
       MAX(price) FILTER (WHERE day_name = 'Tuesday') as Tuesday,
       MAX(price) FILTER (WHERE day_name = 'Wednesday') as Wednesday,
       MAX(price) FILTER (WHERE day_name = 'Thursday') as Thursday,
       MAX(price) FILTER (WHERE day_name = 'Friday') as Friday,
       MAX(price) FILTER (WHERE day_name = 'Saturday') as Saturday
FROM table_1
GROUP BY user_id, name, week_number
ORDER BY user_id, name, week_number;

编辑：

不用FILTER也可以写同样的逻辑：

       MAX(CASE WHEN day_name = 'Sunday' THEN price END) as Sunday,

【讨论】：

感谢它适用于 PostgreSQL 9.4.4 版本。 PostgreSQL 9.3.22 版本是否有等效过滤器？
第二种解决方案也有效。感谢您的支持。