COUNT returns the total count of records in a column or the count for DISTINCT (unique) values selected by the query. : Count « Aggregate Functions « SQL Server / T-SQL Tutorial

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SQL Server / T-SQL Tutorial » Aggregate Functions » Count 




All NULL values are ignored in the total count.


9CREATE TABLE sales(
10>    stor_id        char(4)           NOT NULL,
11>    ord_num        varchar(20)       NOT NULL,
12>    ord_date       datetime          NOT NULL,
13>    qty            smallint          NOT NULL,
14>    payterms       varchar(12)       NOT NULL,
15>    title_id       varchar(80)
16)
17> GO
1insert sales values('1''QA7442.3', '09/13/94', 75'ON Billing','1')
2insert sales values('2''D4482',    '09/14/94', 10'Ne60',    '1')
3insert sales values('3''N914008',  '09/14/94', 20'Ne30',    '2')
4insert sales values('4''N914014',  '09/14/94', 25'Ne30',    '3')
5insert sales values('5''423LL922', '09/14/94', 15'ON Billing','3')
6insert sales values('6''423LL930', '09/14/94', 10'ON Billing','2')
7> GO

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)

(rows affected)
1>
2>
3select COUNT(qtyfrom sales;
4> GO

-----------
          6

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














9.3.Count
9.3.1.COUNT returns the total count of records in a column or the count for DISTINCT (unique) values selected by the query.
9.3.2.COUNT(*) returns the total count of all records (rows) in the column, including NULL values of selected records by the query.
9.3.3.Count function with column alias
9.3.4.Counting unique values.
9.3.5.A common mistake with DISTINCT is to code the DISTINCT statement before the COUNT statement.
9.3.6.Counting values including NULL values.
9.3.7.Using ISNULL to count all values including NULLs.
9.3.8.Count table row in dynamic sql
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