Question

我的表应如下所示：

slno      sheetno   time_stamp
1         101       2018-05-27 11:16:58 
2         103       2018-05-27 11:20:18 
3         102       2018-05-27 11:24:39 
4         105       2018-05-27 11:27:44 
5         106       2018-05-27 11:34:03 
6         107       2018-05-27 11:51:32 
7         108       2018-05-27 12:41:34 
8         109       2018-05-27 12:48:13 
9         110       2018-05-27 12:52:40 
10        111       2018-05-27 13:18:59 
11        112       2018-05-27 14:13:07 
12        113       2018-05-27 14:18:04 
13        114       2018-05-27 14:21:12 
14        115       2018-05-27 14:54:01 
15        117       2018-05-27 14:55:14 
16        118       2018-05-27 14:57:31 
17        119       2018-05-27 15:05:30 
18        120       2018-05-27 15:30:44 
19        121       2018-05-27 15:46:38 
20        122       2018-05-27 16:02:16 
21        123       2018-05-28 11:32:10 
22        124       2018-05-28 11:38:18 
23        125       2018-05-28 11:49:45 
24        126       2018-05-28 11:52:09 
25        127       2018-05-28 12:21:00 
26        128       2018-05-28 12:24:33 
27        129       2018-05-28 13:04:56 
28        130       2018-05-28 14:10:07 
29        140       2018-05-28 14:18:47 
30        141       2018-05-28 14:22:09 
31        142       2018-05-28 14:28:04 
32        143       2018-05-28 14:37:53 
33        144       2018-05-28 15:06:27 
34        145       2018-05-28 15:33:05 
35        146       2018-05-28 15:35:44 
36        147       2018-05-28 15:53:41 
37        148       2018-05-28 16:13:16 
38        149       2018-05-28 16:27:51 
39        150       2018-05-28 16:38:54 
40        151       2018-05-28 16:44:54

我的输出应该是这样的：

From           To            Total No of days   FN   AN
27-05-2018     28-05-2018    2                  2    2

这是我的查询：

SELECT
    DATE_FORMAT(MIN(time_stamp), '%Y-%m-%d') AS min,
    DATE_FORMAT(MAX(time_stamp), '%Y-%m-%d') AS max,
    COUNT(DISTINCT DATE(time_stamp)) AS cnt,
    COUNT(CASE WHEN  TIME(time_stamp) < '12:00:00' THEN 1 END) AS FN,
    COUNT(CASE WHEN TIME(time_stamp) >= '12:00:00' THEN 1 END) AS AN 
FROM master_tab;

“ FN”，“ AN”的输出应分组。如何解决呢？我试图将DISTINCT放在显示我有价值的情况前面。

Answer 1

您似乎在正确的轨道上：

SELECT
    DATE_FORMAT(MIN(time_stamp), '%Y-%m-%d') AS min,
    DATE_FORMAT(MAX(time_stamp), '%Y-%m-%d') AS max,
    COUNT(DISTINCT DATE(time_stamp)) AS cnt,
    COUNT(CASE WHEN TIME(time_stamp) < '12:00:00' THEN 1 END) AS FN,
    COUNT(CASE WHEN TIME(time_stamp) >= '12:00:00' THEN 1 END) AS VA
FROM master_tab;

Demo

注意：

要选择最小/最大日期，没有必要进行额外的强制类型转换，因为DATE_FORMAT已经将这些值仅用作日期。
对于不同的日期计数也是如此；请注意，DISTINCT在MySQL中不是一个函数，而是一个关键字
FN（上午）和VA（晚上）时间的条件计数在存在匹配项时计数为1，否则计数NULL。请注意，NULL将忽略COUNT，因此我们仅对记录进行匹配。 ELSE条件（已省略）默认为NULL。

Answer 2

您可以尝试以下查询：

SELECT
    DATE_FORMAT(MIN(time_stamp), '%Y-%m-%d') AS min,
    DATE_FORMAT(MAX(time_stamp), '%Y-%m-%d') AS max,
    COUNT(DISTINCT DATE(time_stamp)) AS cnt,
    COUNT(DISTINCT CONCAT(DATE(time_stamp),(CASE WHEN TIME(time_stamp) < '12:00:00' THEN 1 END))) AS FN,
    COUNT(DISTINCT CONCAT(DATE(time_stamp),(CASE WHEN TIME(time_stamp) >= '12:00:00' THEN 1 END))) AS VA
FROM master_tab;

和输出

min         max         cnt FN  VA
2018-05-27  2018-05-28  2   2   2

Demo

如何根据输出编写一个mysql查询？

2 个答案:

Demo