SQL query : select max of 2 columns of same row

I would use order by:

select column1, column2
from t
order by column1 desc, column2 desc
fetch first 1 row only;

I see you are using MS Access, so this is phrased as:

select top (1) column1, column2
from t
order by column1 desc, column2 desc;

The only challenge with this approach is that is might return multiple rows, if you have duplicates in the data. If this is an issue, either include a unique id as the last key in the order by:

order by column1 desc, column2 desc, id;

Or use aggregation:

select max(column1), max(column2)
from (select top (1) column1, column2
      from t
      order by column1 desc, column2 desc
     ) as t;

The max() only serves to reduce the result set to a single row (in the event of duplicates). Because all the values from the subquery would be the same, almost any aggregation function would work.

For your sample data, this will work:

SELECT Column1, Column2
FROM yourTable
WHERE Column1 = (SELECT MAX(Column1) FROM yourTable)

Based on your comment

and after that the max of column2

You probably want this instead:

SELECT Column1, MAX(Column2) as Column2
FROM yourTable
WHERE Column1 = (SELECT MAX(Column1) FROM yourTable)
GROUP BY Column1

This handles cases where there are multiple rows with the MAX(Column1), and only returns the row among those with MAX(Column2)

If you want the whole row that has the max value of column1, try this...

SELECT TOP 1 * 
FROM   tablename 
ORDER  BY column1 DESC 

Sample Date

+---------+---------+
| Column1 | Column2 |
+---------+---------+
| 1       |       1 |
| 3       |       2 |
| 1       |       3 |
| 2       |       1 |
| 2       |       4 |
+---------+---------+

Output

+----------+----------+
| Column1  |  Column2 |
+----------+----------+
| 3        |        2 |
+----------+----------+

if you want the max values of both column1 and column2, try this...

SELECT MAX(column1) as column1, 
       MAX(column2) as column2
FROM   tablename 

Sample Date

+---------+---------+
| Column1 | Column2 |
+---------+---------+
| 1       |       1 |
| 3       |       2 |
| 1       |       3 |
| 2       |       1 |
| 2       |       4 |
+---------+---------+

Output

+----------+----------+
| Column1  |  Column2 |
+----------+----------+
| 3        |        4 |
+----------+----------+

I'm hard time to interpret your table but there are built-in functions in SQL that would help in your queries.

SELECT MAX(column1), MAX(column2)
FROM table_name
WHERE condition;