如何根据输出编写一个mysql查询？

Question

My table should be like this:

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

My output should be like this:

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

This is my query :

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;

The output of 'FN' ,'AN' should be grouped. How to solve this? I've tried to put DISTINCT in front of case it shows i value.

Answer 1

You seem to be on the right track:

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

Notes:

• To select the min/max dates, there is no sense in doing an extra cast to date, because DATE_FORMAT will already these values as dates only.
• Same is true for the distinct date count; note that DISTINCT is not a function in MySQL, but rather a keyword
• The conditional counts for FN (morning) and VA (evening) times count the number 1 when there is a match, and count NULL otherwise. Note that NULL is ignored by COUNT , so we only tally matching records. The ELSE condition, which is omitted, defaults to NULL .

Answer 2

You can try following query:

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;

And the output

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

Demo