All NULL values are ignored in the computation for the total and the record count.
computes the average on the rows selected by the query, or the DISTINCT rows.
The return datatype is the same datatype as the column being averaged.
Only the numeric datatypes can be used with the AVG function.
6> CREATE TABLE sales(
7> stor_id char(4) NOT NULL,
8> ord_num varchar(20) NOT NULL,
9> ord_date datetime NOT NULL,
10> qty smallint NOT NULL,
11> payterms varchar(12) NOT NULL,
12> title_id varchar(80)
13> )
14> GO
1> insert sales values('1', 'QA7442.3', '09/13/94', 75, 'ON Billing','1')
2> insert sales values('2', 'D4482', '09/14/94', 10, 'Net 60', '1')
3> insert sales values('3', 'N914008', '09/14/94', 20, 'Net 30', '2')
4> insert sales values('4', 'N914014', '09/14/94', 25, 'Net 30', '3')
5> insert sales values('5', '423LL922', '09/14/94', 15, 'ON Billing','3')
6> insert sales values('6', '423LL930', '09/14/94', 10, 'ON Billing','2')
7> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2>
3> select avg(qty) from sales;
4> GO
-----------
25
(1 rows affected)
1>
2> drop table sales;
3>
4> GO
1>