SQL Server/T-SQL/Table Joins/INNER JOIN
Содержание
Inner join with condition on joined field
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int )
5> GO
1>
2> create table job(
3> ID int,
4> title nvarchar (10),
5> averageSalary int)
6> GO
1>
2>
3> insert into employee (ID, name, salary) values (1, "Jason", 1234)
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (2, "Robert", 4321)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (3, "Celia", 5432)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (4, "Linda", 3456)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (5, "David", 7654)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (6, "James", 4567)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (7, "Alison", 8744)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (8, "Chris", 9875)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (9, "Mary", 2345)
2> GO
(1 rows affected)
1>
2> insert into job(ID, title, averageSalary) values(1,"Developer",3000)
3> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(2,"Tester", 4000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(3,"Designer", 5000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(4,"Programmer", 6000)
2> GO
(1 rows affected)
1>
2>
3> select * from employee;
4> GO
ID name salary
----------- ---------- -----------
1 Jason 1234
2 Robert 4321
3 Celia 5432
4 Linda 3456
5 David 7654
6 James 4567
7 Alison 8744
8 Chris 9875
9 Mary 2345
(9 rows affected)
1> select * from job;
2> GO
ID title averageSalary
----------- ---------- -------------
1 Developer 3000
2 Tester 4000
3 Designer 5000
4 Programmer 6000
(4 rows affected)
1>
2>
3> SELECT p.ID, s.title, p.Name
4> FROM Employee p
5> INNER JOIN Job s
6> ON p.ID = s.ID
7> WHERE p.ID < 4
8> GO
ID title Name
----------- ---------- ----------
1 Developer Jason
2 Tester Robert
3 Designer Celia
(3 rows affected)
1>
2>
3>
4> drop table employee;
5> drop table job;
6> GO
1>
2>
"INNER JOIN" with different syntax
1>
2>
3> create table employee(
4> ID int,
5> name nvarchar (10),
6> salary int )
7> GO
1>
2> create table job(
3> ID int,
4> title nvarchar (10),
5> averageSalary int)
6> GO
1>
2>
3> insert into employee (ID, name, salary) values (1, "Jason", 1234)
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (2, "Robert", 4321)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (3, "Celia", 5432)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (4, "Linda", 3456)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (5, "David", 7654)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (6, "James", 4567)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (7, "Alison", 8744)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (8, "Chris", 9875)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (9, "Mary", 2345)
2> GO
(1 rows affected)
1>
2> insert into job(ID, title, averageSalary) values(1,"Developer",3000)
3> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(2,"Tester", 4000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(3,"Designer", 5000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(4,"Programmer", 6000)
2> GO
(1 rows affected)
1>
2>
3> select * from employee;
4> GO
ID name salary
----------- ---------- -----------
1 Jason 1234
2 Robert 4321
3 Celia 5432
4 Linda 3456
5 David 7654
6 James 4567
7 Alison 8744
8 Chris 9875
9 Mary 2345
(9 rows affected)
1> select * from job;
2> GO
ID title averageSalary
----------- ---------- -------------
1 Developer 3000
2 Tester 4000
3 Designer 5000
4 Programmer 6000
(4 rows affected)
1>
2>
3> -- INNER JOINs
4>
5> SELECT * FROM Employee
6> INNER JOIN job
7> ON Employee.ID = Job.ID
8>
9> GO
ID name salary ID title averageSalary
----------- ---------- ----------- ----------- ---------- -------------
1 Jason 1234 1 Developer 3000
2 Robert 4321 2 Tester 4000
3 Celia 5432 3 Designer 5000
4 Linda 3456 4 Programmer 6000
(4 rows affected)
1>
2>
3>
4> drop table employee;
5> drop table job;
6> GO
1>
Using the * operator to reference entire row
1>
2> create table employee(
3> ID int,
4> name nvarchar (10),
5> salary int )
6> GO
1>
2> create table job(
3> ID int,
4> title nvarchar (10),
5> averageSalary int)
6> GO
1>
2>
3> insert into employee (ID, name, salary) values (1, "Jason", 1234)
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (2, "Robert", 4321)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (3, "Celia", 5432)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (4, "Linda", 3456)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (5, "David", 7654)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (6, "James", 4567)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (7, "Alison", 8744)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (8, "Chris", 9875)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (9, "Mary", 2345)
2> GO
(1 rows affected)
1>
2> insert into job(ID, title, averageSalary) values(1,"Developer",3000)
3> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(2,"Tester", 4000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(3,"Designer", 5000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(4,"Programmer", 6000)
2> GO
(1 rows affected)
1>
2>
3> select * from employee;
4> GO
ID name salary
----------- ---------- -----------
1 Jason 1234
2 Robert 4321
3 Celia 5432
4 Linda 3456
5 David 7654
6 James 4567
7 Alison 8744
8 Chris 9875
9 Mary 2345
(9 rows affected)
1> select * from job;
2> GO
ID title averageSalary
----------- ---------- -------------
1 Developer 3000
2 Tester 4000
3 Designer 5000
4 Programmer 6000
(4 rows affected)
1>
2> -- Using the * operator
3>
4>
5> SELECT Employee.* FROM Employee
6> INNER JOIN Job
7> ON Employee.ID = Job.ID
8> GO
ID name salary
----------- ---------- -----------
1 Jason 1234
2 Robert 4321
3 Celia 5432
4 Linda 3456
(4 rows affected)
1>
2>
3> drop table employee;
4> drop table job;
5> GO
1>
Working with "INNER JOIN"
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int )
5> GO
1>
2> create table job(
3> ID int,
4> title nvarchar (10),
5> averageSalary int)
6> GO
1>
2>
3> insert into employee (ID, name, salary) values (1, "Jason", 1234)
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (2, "Robert", 4321)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (3, "Celia", 5432)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (4, "Linda", 3456)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (5, "David", 7654)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (6, "James", 4567)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (7, "Alison", 8744)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (8, "Chris", 9875)
2> GO
(1 rows affected)
1> insert into employee (ID, name, salary) values (9, "Mary", 2345)
2> GO
(1 rows affected)
1>
2>
3> insert into job(ID, title, averageSalary) values(1,"Developer",3000)
4> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(2,"Tester", 4000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(3,"Designer", 5000)
2> GO
(1 rows affected)
1> insert into job(ID, title, averageSalary) values(4,"Programmer", 6000)
2> GO
(1 rows affected)
1>
2> select * from employee;
3> GO
ID name salary
----------- ---------- -----------
1 Jason 1234
2 Robert 4321
3 Celia 5432
4 Linda 3456
5 David 7654
6 James 4567
7 Alison 8744
8 Chris 9875
9 Mary 2345
(9 rows affected)
1> select * from job;
2> GO
ID title averageSalary
----------- ---------- -------------
1 Developer 3000
2 Tester 4000
3 Designer 5000
4 Programmer 6000
(4 rows affected)
1>
2>
3> SELECT e.ID, e.Name, j.title
4> FROM Employee e INNER JOIN Job j
5> ON e.Id = j.ID
6> GO
ID Name title
----------- ---------- ----------
1 Jason Developer
2 Robert Tester
3 Celia Designer
4 Linda Programmer
(4 rows affected)
1>
2>
3>
4> drop table employee;
5> drop table job;
6> GO
1>