Selecting titles that sell more than the average. : AVG « Aggregate Functions « SQL Server / T-SQL Tutorial






3>
4>
5> CREATE TABLE titles(
6>    title_id       varchar(20),
7>    title          varchar(80)       NOT NULL,
8>    type           char(12)          NOT NULL,
9>    pub_id         char(4)               NULL,
10>    price          money                 NULL,
11>    advance        money                 NULL,
12>    royalty        int                   NULL,
13>    ytd_sales      int                   NULL,
14>    notes          varchar(200)          NULL,
15>    pubdate        datetime          NOT NULL
16> )
17> GO
1>
2> insert titles values ('1', 'Secrets',   'popular_comp', '1389', $20.00, $8000.00, 10, 4095,'Note 1','06/12/94')
3> insert titles values ('2', 'The',       'business',     '1389', $19.99, $5000.00, 10, 4095,'Note 2','06/12/91')
4> insert titles values ('3', 'Emotional', 'psychology',   '0736', $7.99,  $4000.00, 10, 3336,'Note 3','06/12/91')
5> insert titles values ('4', 'Prolonged', 'psychology',   '0736', $19.99, $2000.00, 10, 4072,'Note 4','06/12/91')
6> insert titles values ('5', 'With',      'business',     '1389', $11.95, $5000.00, 10, 3876,'Note 5','06/09/91')
7> insert titles values ('6', 'Valley',    'mod_cook',     '0877', $19.99, $0.00,    12, 2032,'Note 6','06/09/91')
8> insert titles values ('7', 'Any?',      'trad_cook',    '0877', $14.99, $8000.00, 10, 4095,'Note 7','06/12/91')
9> insert titles values ('8', 'Fifty',     'trad_cook',    '0877', $11.95, $4000.00, 14, 1509,'Note 8','06/12/91')
10> GO

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)
1>
2> CREATE TABLE sales(
3>    stor_id        char(4)           NOT NULL,
4>    ord_num        varchar(20)       NOT NULL,
5>    ord_date       datetime          NOT NULL,
6>    qty            smallint          NOT NULL,
7>    payterms       varchar(12)       NOT NULL,
8>    title_id       varchar(80)
9> )
10> 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>      SELECT    titles.title, titles.price
3>      FROM      titles JOIN sales ON sales.title_id = titles.title_id
4>      WHERE     sales.qty >
5>                (SELECT AVG(qty)
6>                FROM sales)
7> GO
title                                                                            price
-------------------------------------------------------------------------------- ---------------------
Secrets                                                                                        20.0000

(1 rows affected)
1>
2> drop table sales;
3> drop table titles;
4> GO








9.2.AVG
9.2.1.AVG calculates the average for selected records of numeric data in a column or the average for DISTINCT (unique) values of the selected records.
9.2.2.Using DISTINCT in Aggregate Functions
9.2.3.A summary query that uses the COUNT, AVG, and SUM functions
9.2.4.adds the WHERE statement to calculate the average
9.2.5.Selecting titles that sell more than the average.
9.2.6.CAST(AVG(dec1) AS dec(5,2))