How to make a query of the max month/year of a group of columns - sql

Question

I don't really know how to make a MySQL query where I get all the data(Columns) of the most present month + year.
Being a little bit more specific I need to group the columns (description, data1, data2, data3) and only get the one that has the highest month + year.
The table contains data like this one:
description data1 data2 data3 year month adddate
desc1 0 7 1 2019 5 2019-05-23
desc2 0 7 1 2019 5 2019-05-23
desc3 1 7 1 2019 5 2019-05-23
desc4 0 2 1 2018 12 2019-05-23
I've tried using max on the month, year and adddate.
select description, data1, data2, data3, max(year) as year, max(month) as month, max(adddate) as adddate
from tabledata
group by description, data1, data2, data3
But with this I'm getting that the max register is desc2 with the month 12 which is not correct since the month is desc2 is 6.

Answer 1

You need to get the max value of an expression like:
100 * year + month
or
12 * year + month
So do this:
select *
from tabledata
where 100 * year + month = (
select max(100 * year + month)
from tabledata
)
See the demo.
Results:
> description | data1 | data2 | data3 | year | month | adddate
> :---------- | ----: | ----: | ----: | ---: | ----: | :---------
> desc1 | 0 | 7 | 1 | 2019 | 5 | 23/05/2019
> desc2 | 0 | 7 | 1 | 2019 | 5 | 23/05/2019
> desc3 | 1 | 7 | 1 | 2019 | 5 | 23/05/2019

Answer 2

You need to find the max combination of year and month (MaxYearMonth) and then join to your table again to find all the rows that match that MaxYearMonth. Here is the solution for SQL Server...
IF OBJECT_ID('tempdb.dbo.#tabledata', 'U') IS NOT NULL DROP TABLE #tabledata;
CREATE TABLE #tabledata
(
description VARCHAR(10)
, data1 INT
, data2 INT
, data3 INT
, year INT
, month INT
, adddate DATE
);
INSERT INTO #tabledata VALUES ('desc1', 0, 7, 1, 2019, 5, '2019-05-23')
INSERT INTO #tabledata VALUES ('desc2', 0, 7, 1, 2019, 5, '2019-05-23')
INSERT INTO #tabledata VALUES ('desc3', 1, 7, 1, 2019, 5, '2019-05-23')
INSERT INTO #tabledata VALUES ('desc4', 0, 2, 1, 2018, 12, '2019-05-23')
select a.description, a.data1, a.data2, a.data3
from #tabledata a
inner join
(
select max(convert(char(4), year) + right('0' + convert(varchar(2), month), 2)) as [MaxYearMonth]
from #tabledata
) b on convert(char(4), a.year) + right('0' + convert(varchar(2), a.month), 2) = b.MaxYearMonth
Yields this...
description data1 data2 data3
----------- ----------- ----------- -----------
desc1 0 7 1
desc2 0 7 1
desc3 1 7 1
Click here to see it in action.
You mention "mysql" so if you are really using mySQL then the syntax will likely need to change a bit.