Multiple choice technology databases

The standard EMP table contains 14 records corresponding to the employess of the corporation.One of those records has a NULL value stored in the MGR column.If Issue the following command on the table: select count(mgr) from emp; What is the count?

  1. 14

  2. >14

  3. error

  4. <14

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The COUNT(column) function ignores NULL values. Since one of the 14 records has a NULL value in the mgr column, COUNT(mgr) will return 13, which is less than 14.