SQL query

Question

when we calculated avg fun in sql then we exclude the null value or not in count (sum/count)

somewhere it consider null vlaue also in count soomwher not??

wht is actual procedure

Answer 1

The COUNT(column_name) function returns the number of values (NULL values will not be counted) of the specified column.

The COUNT(*) function returns the number of records in a table either null or non null.

The COUNT(DISTINCT column_name) function returns the number of distinct non null values of the specified column.

Answer 2

The COUNT(column_name) function returns the number of values (NULL values will not be counted) of the specified column.

The COUNT(*) function returns the number of records in a table either null or non null.

So average salary = sum(salary)/ count (salary).

if a value is null out of 4  then count (salary) will give 3
so average will be sum / 3 while actually result should be divided by 4