MySQL日期范围多列计数和按选择语句分组

Question

我有一个查询，我一直在努力了一段时间，但我似乎无法得到它。这里的其他答案适用于计算某个日期范围内的金额，然后按日期分组以获得计数。不过，我需要按日期对两列进行计数和分组。

比如这里是我试图去工作查询：

(SELECT COUNT(*) arrived, DATE(arrived) date, 'arrived' AS source 
FROM products 
WHERE arrived BETWEEN '2016-01-01' AND '2016-01-31' 
GROUP BY DATE(date) 
ORDER BY date ASC) 

UNION ALL 

(SELECT COUNT(*) released, DATE(released) date, 'released' AS source 
FROM products 
WHERE released BETWEEN '2016-01-01' AND '2016-01-31' 
GROUP BY DATE(date) 
ORDER BY date ASC) 

然而，这返回如下：

arrived date  source 
3  2016-01-12 arrived 
2  2016-01-28 arrived 
1  2016-01-29 arrived 
1  2016-01-05 released 

我所需要的是这样的：

date   arrived released 
2016-01-05  0   1 
2016-01-12  3   0 
2016-01-28  2   0 
2016-01-29  1   0 

有什么建议吗？谢谢。

Answer 1

你可以申请有条件聚集由一个UNION ALL操作所获得的派生表“到达”和“释放”日期：

SELECT `date`, 
     COUNT(CASE WHEN type = 'arrived' THEN 1 END) AS arrived, 
     COUNT(CASE WHEN type = 'released' THEN 1 END) AS released 
FROM (
    SELECT arrived AS `date`, 'arrived' as type 
    FROM products 
    WHERE arrived BETWEEN '2016-01-01' AND '2016-01-31' 

    UNION ALL 

    SELECT released AS `date`, 'released' as type 
    FROM products 
    WHERE released BETWEEN '2016-01-01' AND '2016-01-31') AS t 
GROUP BY `date` 

Demo here