如何组合同一列中具有相同数据的多行？

Question

我的代码是：

SELECT datepart(year, request_created_date) AS request_year, 
    datepart(month, request_created_date) AS request_month, 
    datepart(week, request_created_date) AS request_week, 
    count(request_id) AS request_count 
FROM nyc311_requests 
GROUP BY request_created_date 
ORDER BY request_week 

在我得到的输出，我有两排，其中request_week是36个7行，其中它是37.我想要的是列一样，合并成一排。

Answer 1

如果你要使用GROUP BY子句，你将不得不包括所有其他比GROUP BY计算字段的字段：

SELECT datepart(year, request_created_date) AS request_year, 
    datepart(month, request_created_date) AS request_month, 
    datepart(week, request_created_date) AS request_week, 
    count(request_id) AS request_count 
FROM nyc311_requests 
GROUP BY datepart(year, request_created_date), 
    datepart(month, request_created_date), 
    datepart(week, request_created_date) 
ORDER BY request_week 

或者，如果你想有一个更清洁寻找查询：

SELECT M.*, count(*) AS request_count FROM 
(
    SELECT datepart(year, request_created_date) AS request_year, 
     datepart(month, request_created_date) AS request_month, 
     datepart(week, request_created_date) AS request_week 
    FROM nyc311_requests 
)AS M 
GROUP BY M.request_year, M.request_month, M.request_week 
ORDER BY M.request_week