|
This form of COUNT does not count rows with null values for the column.
4>
5>
6> CREATE TABLE employee(
7> id INTEGER NOT NULL PRIMARY KEY,
8> first_name VARCHAR(10),
9> last_name VARCHAR(10),
10> salary DECIMAL(10,2),
11> start_Date DATETIME,
12> region VARCHAR(10),
13> city VARCHAR(20),
14> managerid INTEGER
15> );
16> GO
1> INSERT INTO employee VALUES (1, 'Jason' , 'Martin', 5890,'2005-03-22','North','Vancouver',3);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (2, 'Alison', 'Mathews',4789,'2003-07-21','South','Utown',4);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (3, 'James' , 'Smith', 6678,'2001-12-01','North','Paris',5);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (4, 'Celia' , 'Rice', 5567,'2006-03-03','South','London',6);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (5, 'Robert', 'Black', 4467,'2004-07-02','East','Newton',7);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (6, 'Linda' , 'Green' , 6456,'2002-05-19','East','Calgary',8);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (7, 'David' , 'Larry', 5345,'2008-03-18','West','New York',9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (8, 'James' , 'Cat', 4234,'2007-07-17','West','Regina',9);
2> GO
(1 rows affected)
1> INSERT INTO employee VALUES (9, 'Joan' , 'Act', 6123,'2001-04-16','North','Toronto',10);
2> GO
(1 rows affected)
1>
2> select * from employee;
3> GO
id first_name last_name salary start_Date region city managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
1 Jason Martin 5890.00 2005-03-22 00:00:00.000 North Vancouver 3
2 Alison Mathews 4789.00 2003-07-21 00:00:00.000 South Utown 4
3 James Smith 6678.00 2001-12-01 00:00:00.000 North Paris 5
4 Celia Rice 5567.00 2006-03-03 00:00:00.000 South London 6
5 Robert Black 4467.00 2004-07-02 00:00:00.000 East Newton 7
6 Linda Green 6456.00 2002-05-19 00:00:00.000 East Calgary 8
7 David Larry 5345.00 2008-03-18 00:00:00.000 West New York 9
8 James Cat 4234.00 2007-07-17 00:00:00.000 West Regina 9
9 Joan Act 6123.00 2001-04-16 00:00:00.000 North Toronto 10
(9 rows affected)
1>
2> SELECT region, COUNT(DISTINCT region) job_count
3> FROM employee
4> GROUP BY region
5> GO
region job_count
---------- -----------
East 1
North 1
South 1
West 1
(4 rows affected)
1> drop table employee;
2> GO
|