difference between inner join and outer join

. The Inner join combines the records in these tables only if there is a matching value on the public field of the two tables.The ability to use INNER JOIN for departments and Employees tables to select all employees in each department. Instead, you can create an outer

[Test @ ora1] SQL> select * From A; No. Name ---- ---------- 1000 Zhang San 2000 Li Si 3000 Wang Wu [test @ ora1] SQL> select * from B; product NO. ---- ---------- 1000 TV set 2000 video recorder 4000 bicycle [test @ ora1] SQL> set null Null Value -- Here I define null as [null value] [test @ ora1] SQL> select. *, B. * From a inner join B on. no. = B. no.; No. name No. Product ---- ---------- 1000 Zhang San

Connections include: internal connection, external connection, and cross connection.1. Internal Connection-the most commonDefinition:Only the rows in the two tables that meet the connection conditions are combined as the result set.In the internal join, only matching rows in two tables can appear in the result set.Keywords:INNER JOINFormat:SELECT column table FROM table name 1 [INNER]

SQL left join, right join, and inner join Today, I chatted with a friend about a small problem in their company. As follows: Table A device table stores MAC addresses, provinces, cities, and zones.Table B Software Table, which stores MAC addresses and software names.You can query the Software List by province, city, or

Outer Join, left Outer Join Definition: Used to query records that meet the connection conditions and do not meet the connection conditions. Query emp table records SELECT * FROM emp;Empno ename job mgr hiredate sal comm deptno1 7369 smith clerk 7902 800.00 202 7499 allen salesman 7698 1600.00 300.00 303 7521 ward sale

In the following post, innerjoin = where = join Http://baike.360.cn/4241488/12057813.html Http://z.baidu.com/question/46996912.html? SI = 1 The connection statement used in the WHERE clause is called a recessive connection in the database language. Inner join ...... The connection generated by the on clause is called an explicit connection. (Other

1 LEFT JOIN: The query results are based on the left table data. If the left table has four data, the right table has three data, the query result is four, and all the data in the left table.For example:EMP Table:Sal table:Left connection Select * from EMP left join SAL on EMP. ename = SAL.ename; Left JOIN, the table EMP is the primary table, so the q

in Table A and table B is like this. a b id name id stock 1 a 1 15 2 b 2 50 3 c select * from a inner join b on a.id=b.id This syntax is an internal join in the connection query.

Connections include: internal connection, external connection, and cross connection.1. Internal Connection-the most commonDefinition:Only the rows in the two tables that meet the connection conditions are combined as the result set.In the internal join, only matching rows in two tables can appear in the result set.Keywords:INNER JOINFormat:SELECT column table FROM table name 1 [INNER]

Data Table connection (left join, right join, inner join, Cartesian) -- Query analyzer execution:-- Create Table Table1, Table2:Create Table Table1 (ID int, name varchar (10 ))Create Table Table2 (ID int, score INT)Insert into Table1 select 1, 'lil'Insert into Table1 select 2, 'zhang'Insert into Table1 select

1. The connection statement used in the WHERE clause, in the database language, is called an implicit connection. INNER JOIN ... An ON clause produces a connection called a dominant connection. (Other join parameters are also dominant connections) the connection between the WHERE and the inner