The SUM() function ignores NULL . It means that SUM() doesn’t consider the NULL in calculation. If you use the DISTINCT option, the SUM() function calculates the sum of distinct values. For example, without the DISTINCT option, the SUM() of 1, 1, 8, and 2 will return 12.
Does sum return NULL?
If there are no rows, sum() will return null . It will also return null if all rows have a null balance.
How does sum handle NULL SQL?
- The aggregate functions in SQL ( SUM , COUNT , AVG , MAX , MIN ) do not handle NULL values and eliminate them before performing any calculations. …
- In the case of GROUP BY clause, if a column contains rows with NULL values, then those will be grouped into one group.
