I'm new to mysql. I'm trying to write a query to calculate the total and difference for multiple rows, and then put them in specific columns.
Eg. I want to sum all Entity'A' of Type'1' then subtract from the result, the sum of Entity'A' of type'0'. While simultaneously populating a table to show where this difference is positive or negative.
Sample table:
Entity Type Value
A 1 200
B 1 500
C 0 350
B 0 150
C 1 100
A 1 50
A 1 350
Expected Output:
Entity Diff-Positive Diff-Negative
A 600
B 350
C 250
Note that Entity'A' for example may not have an entry for Type'0'
This is basically aggregation. You need a conditional to split the values into separate columns. One way uses greatest()
:
select entity,
greatest(sum(case when type = 1 then value else - value end), 0) as diff_positive,
greatest(sum(case when type = 0 then value else - value end), 0) as diff_positive
from t
group by entity;
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.