Table number contains many numbers in column num including duplicated ones.
Can you write a SQL query to find the biggest number, which only appears once.
+---+ |num| +---+ | 8 | | 8 | | 3 | | 3 | | 1 | | 4 | | 5 | | 6 |
For the sample data above, your query should return the following result:
+---+ |num| +---+ | 6 |
Note:
If there is no such number, just output null.
Code
SELECT MAX(num) as num FROM (SELECT num FROM number GROUP BY num HAVING COUNT(num) = 1) AS t # note : have to has AS t