How do i sum fields inside a column? - mysql

Question

I have a table like this: Table Name: Accounting
year
acc
value
2018
in
500
2018
out
500
2019
in
600
2019
out
800
I need to show up to 10-year slots with the highest value (i.e in + out). For example, in this case, 2019 is the highest, my query should show
year
Max Value
2019
1400
My current SQL code is:
SELECT year,acc, MAX(value) as max_value
FROM Accounting
group by year,acc
LIMIT 10
How can I get the desired result?

Answer 1

You need SUM() and ORDER BY:
SELECT year,acc, SUM(value) as sum_value
FROM Accounting
GROUP BY year
ORDER BY sum_value DESC
LIMIT 1;
If you want only ten years to be considered, you need a WHERE clause, for instance:
SELECT year, SUM(value) as sum_value
FROM Accounting
WHERE year >= 2010
GROUP BY year
ORDER BY sum_value DESC
LIMIT 1;

Answer 2

I may be misunderstanding your question, but what it appears you are attempting to complete the following steps.
You are trying to SUM by year, regardless of account type, the amount in the value column.
You are trying to show only the years with the 10 highest summed values over some specified period of time.
One way to approach this would be as follows
SELECT year, SUM(value) as annual_value
FROM Accounting
GROUP BY year
ORDER BY annual_value desc
LIMIT 10

Answer 3

You have to use the SUM() not the MAX(), because you don't want only the highest value, but the total, and then you only have to GROUP BY them by year
SELECT year,sum(value) as max_value
FROM Accounting
group by year
LIMIT 10;
Here's the result:
+------+-----------+
| year | max_value |
+------+-----------+
| 2018 | 1000 |
| 2019 | 1400 |
+------+-----------+