Mysql - SQL Aggregate Over Range of Values

bvowe
September 29, 2022
174 views
2 votes
4 Answers

I have T1 which is formatted as

STUDENT SCORE   DATE
1   6   2022-02-01
1   0   2022-03-12
1   5   2022-04-30
1   1   2022-04-30
1   1   2022-05-14
1   1   2022-05-19
1   8   2022-05-26
2   9   2022-01-02
2   10  2022-04-11
2   2   2022-04-12
2   0   2022-04-17
2   7   2022-05-08
2   4   2022-05-12
3   10  2022-01-09
3   2   2022-02-11
3   6   2022-03-16
3   3   2022-03-18
3   2   2022-04-02
3   9   2022-04-27
4   4   2022-02-24
4   0   2022-02-26
4   9   2022-02-28
4   2   2022-03-27
4   8   2022-04-02
4   4   2022-04-14
5   3   2022-01-28
5   5   2022-02-12
5   6   2022-02-18
5   0   2022-02-21
5   4   2022-04-05
XX  0.711094564 2022-02-28
XX  0.60584994  2022-03-31
XX  0.087965016 2022-04-30
YY  0.497937992 2022-02-28
YY  0.727796963 2022-03-31
YY  0.974471085 2022-04-30
YY  0.780187398 2022-05-30

First I wish to extract the UNIQUE values of DATE when STUDENT equals to XX and YY. There are some duplicates. These are the trimester ending dates.

Then I wish to SUM up the SCORE values for each STUDENT across the date ranges from Step 1:

And together I wish to generate this table T2

STUDENT SCORE   DATE.START  DATE.END
1   6   2022-01-01  2022-02-28
1   0   2022-03-01  2022-03-31
1   6   2022-04-01  2022-04-30
1   10  2022-05-01  2022-05-30
2   9   2022-01-01  2022-02-28
2   NA  2022-03-01  2022-03-31
2   12  2022-04-01  2022-04-30
2   11  2022-05-01  2022-05-30
3   12  2022-01-01  2022-02-28
3   9   2022-03-01  2022-03-31
3   11  2022-04-01  2022-04-30
3   NA  2022-05-01  2022-05-30
4   13  2022-01-01  2022-02-28
4   2   2022-03-01  2022-03-31
4   12  2022-04-01  2022-04-30
4   NA  2022-05-01  2022-05-30
5   14  2022-01-01  2022-02-28
5   NA  2022-03-01  2022-03-31
5   4   2022-04-01  2022-04-30
5   NA  2022-05-01  2022-05-30

And I try this,

WITH T2 AS(
SELECT DISTINCT(DATE),
COALESCE(LEAD(DATE) OVER(ORDER BY DATE) AS DATE.START,
ROW_NUMBER() OVER (ORDER BY DATE) AS DATE.END
FROM T1 WHERE (STUDENT = 'XX' OR STUDENT = 'YY')
)
SELECT STUDENT, SUM(SCORE), DATE.START, DATE.END
FROM T1 JOIN T2 ON T1.DATE.START BETWEEN DATE.START AND DATE.END

Tags: mysql sql

Answers

- Barmar
- September 30, 2022 at 12:51 am
- 0 votes
0
Your date ranges are just month boundaries, so you can use ordinary GROUP BY
```
SELECT student, DATE_FORMAT(date, '%Y-%m') AS year_month, SUM(score) AS score
FROM T1
WHERE student IN ('XX', 'YY')
GROUP BY student, year_month
```
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In this one we’re looking at score by month so we don’t really need the bottom half of the information. In fact, it makes it better not to have it cause then we won’t be able to save student and score as int.

select    student
         ,sum(score)                              as total_score
         ,max(dateadd(day, 1, eomonth(date, -1))) as "DATE.START"
         ,max(eomonth(date))                      as "DATE.END"
from      t
group  by student, year(date), month(date)

student	total_score	DATE.START	DATE.END
1	6	2022-02-01	2022-02-28
1	0	2022-03-01	2022-03-31
1	6	2022-04-01	2022-04-30
1	10	2022-05-01	2022-05-31
2	9	2022-01-01	2022-01-31
2	12	2022-04-01	2022-04-30
2	11	2022-05-01	2022-05-31
3	10	2022-01-01	2022-01-31
3	2	2022-02-01	2022-02-28
3	9	2022-03-01	2022-03-31
3	11	2022-04-01	2022-04-30
4	13	2022-02-01	2022-02-28
4	2	2022-03-01	2022-03-31
4	12	2022-04-01	2022-04-30
5	3	2022-01-01	2022-01-31
5	11	2022-02-01	2022-02-28
5	4	2022-04-01	2022-04-30

Fiddle

Here we create a calendar divided to trimesters and join it with our table matching each date to the correct trimester in the calendar.

DECLARE @Year INT = '2019';
DECLARE @YearCnt INT = 4 ;
DECLARE @StartDate DATE = DATEFROMPARTS(@Year, 01, 01)
DECLARE @EndDate DATE = DATEADD(DAY, -1, DATEADD(YEAR, @YearCnt, @StartDate));

;WITH Cal(n) AS
(
SELECT 0 UNION ALL SELECT n + 4 FROM Cal
WHERE n < DATEDIFF(month, @StartDate, @EndDate)
),
FnlDt(d) AS
(
SELECT DATEADD(month, n, @StartDate) FROM Cal
),
FinalCte AS
(
SELECT
[Date] = CONVERT(DATE,d)

FROM FnlDt
)
select     STUDENT
          ,sum(score) as total_score
          ,semester_start
          ,semester_end
          
from       (
           select   date                                             as semester_start
                   ,lead(dateadd(day, -1, date)) over(order by date) as semester_end
           from     finalCte 
           ) t2 join t on t.date between semester_start and semester_end   
group by   STUDENT, semester_start, semester_end

STUDENT	total_score	semester_start	semester_end
1	12	2022-01-01	2022-04-30
1	10	2022-05-01	2022-08-31
2	21	2022-01-01	2022-04-30
2	11	2022-05-01	2022-08-31
3	32	2022-01-01	2022-04-30
4	27	2022-01-01	2022-04-30
5	18	2022-01-01	2022-04-30

Fiddle

This answer is EXACTLY what the question was asking for, including the hacks to accommodate for the ill-posed specifications. Here it goes…

Select Distinct Date From t1 Where Student = 'XX' or Student = 'YY' Order By date

Select t2.STUDENT as STUDENT,
   COALESCE(CAST(Sum(Case When (t1.DATE is null) Then null
                          When (t1.DATE >= t2.di and t1.DATE <= t2.df) Then t1.SCORE
                          Else 0
        End) AS DECIMAL(2,0)), 'NA') as SCORE, 
   di as "Date.START",
   df as "Date.END"
   From (Select STUDENT, di, df 
                From (Select Distinct STUDENT From t1 Where STUDENT <> 'XX' and STUDENT <> 'YY') as ta,
                     (Select Distinct Case When MONTH(t1.DATE) = 2 Then DATE_SUB(DATE_SUB(t1.DATE,INTERVAL DAYOFMONTH(t1.DATE) - 1 DAY), INTERVAL 31 DAY)
                                           Else DATE_SUB(t1.DATE,INTERVAL DAYOFMONTH(t1.DATE) - 1 DAY)
                                      End as di,
                                       t1.DATE as df
                                  from t1 where STUDENT = 'XX' or STUDENT = 'YY') as tb
         ) as t2
   Left Join t1
         On t2.STUDENT = t1.STUDENT and t1.DATE >= t2.di and t1.DATE <= t2.df 
   Group By t2.STUDENT, t2.df 
   Order By t2.STUDENT, t2.df

In case anyone wants to play with the query, here goes a link to a Fiddle page.

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Mysql – SQL Aggregate Over Range of Values

Answers