Returns the numeric average of all (distinct) values.
avg([all | distinct] expression)
applies avg to all values. all is the default.
eliminates duplicate values before avg is applied. distinct is optional.
is a column name, constant, function, any combination of column names, constants, and functions connected by arithmetic or bitwise operators, or a subquery. With aggregates, an expression is usually a column name. For more information, see “Expressions”.
Calculates the average advance and the sum of total sales for all business books. Each of these aggregate functions produces a single summary value for all of the retrieved rows:
select avg(advance), sum(total_sales) from titles where type = "business"
------------------------ ----------- 6,281.25 30788
Used with a group by clause, the aggregate functions produce single values for each group, rather than for the whole table. This statement produces summary values for each type of book:
select type, avg(advance), sum(total_sales) from titles group by type
type ------------ ------------------------ ----------- UNDECIDED NULL NULL business 6,281.25 30788 mod_cook 7,500.00 24278 popular_comp 7,500.00 12875 psychology 4,255.00 9939 trad_cook 6,333.33 19566
Groups the titles table by publishers and includes only those groups of publishers who have paid more than $25,000 in total advances and whose books average more than $15 in price:
select pub_id, sum(advance), avg(price) from titles group by pub_id having sum(advance) > $25000 and avg(price) > $15
pub_id ------ -------------------- -------------------- 0877 41,000.00 15.41 1389 30,000.00 18.98
avg, an aggregate function, finds the average of the values in a column. avg can only be used on numeric (integer, floating point, or money) datatypes. Null values are ignored in calculating averages.
For general information about aggregate functions, see “Aggregate functions”.
When you average integer data, Adaptive Server treats the result as an int value, even if the datatype of the column is smallint or tinyint. To avoid overflow errors in DB-Library programs, declare all variables for results of averages or sums as type int.
You cannot use avg() with the binary datatypes.
Since the average value is only defined on numeric datatypes, use with Unicode expressions generates an error.
SQL92 – Compliance level: Transact-SQL extension.
Any user can execute avg.
