sql server Right Outer Join用法

Right Outer Join 运算符返回满足第二个（底端）输入与第一个（顶端）输入的每个匹配行的联接的每行。此外，它还返回第二个输入中在第一个输入中没有匹配行的任何行，即与 NULL 联接。如果 Argument 列内不存在任何联接谓词，则每行都是一个匹配行。

一、联接（ join）

通过联接，可以根据各个表之间的逻辑关系从两个或多个表中检索数据。联接表示应如何使用一个表中的数据来选择另一个表中的行。

联接条件通过以下方法定义两个表在查询中的关联方式：

指定每个表中要用于联接的列。典型的联接条件在一个表中指定外键，在另一个表中指定与其关联的键。指定比较各列的值时要使用的逻辑运算符（=、 等）。

下面的 SQL 语句说明 titles 表和 publishers 表之间的左向外联接包括所有的书名，甚至包括那些没有出版商信息的书名： Use pubs    SELECT titles.title_id,    titles.title, publishers.pub_name    FROM titles LEFT OUTER JOIN publishers ON titles.pub_id = publishers.pub_id

实例

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>
4> * from employee;
5> 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> -- RIGHT OUTER JOIN includes all the information from the table on the right.
3>
4> SELECT e.id, e.name, j.title
5> FROM Employee e
6> RIGHT OUTER JOIN job j
7>              ON e.id = j.id
8> GO
id          name       title
----------- ---------- ----------
          1 Jason      Developer
          2 Robert     Tester
          3 Celia      Designer
          4 Linda      Programmer

(4 rows affected)
1>
2>
3> drop table employee;
4> drop table job;
5> GO
1>
2>

实例二 RIGHT OUTER JOIN

外连接（Outer join）语法

左外连接的语法为： SELECT 列 FROM 表1   LEFT   [OUTER]JOIN 表2 ON 表1.列1=表2.列2

右外连接的语法为： SELECT select_list FROM  表1 RIGHT[OUTER]JOIN 表2 ON 表1.列1=表2.列2

全外连接(完整外部联接)的语法为： SELECT select_list FROM  表1 FULL[OUTER]  JOIN  表2 ON 表1.列1=表2.列2

实例

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 e.name FROM Employee e
4> RIGHT OUTER JOIN job j
5>               ON e.id = j.id
6> WHERE e.id IS NOT NULL
7> GO
name
----------
Jason
Robert
Celia
Linda

(4 rows affected)
1>
2>
3> drop table employee;
4> drop table job;
5> GO
1>