difference between inner join and outer join

From: http://www.cnblogs.com/kevinGaoblog/archive/2012/07/05/2577410.html--Execute in Query Analyzer:--Build Table Table1,table2:CREATE TABLE table1 (ID int,name varchar (10))CREATE TABLE table2 (ID int,score int)INSERT INTO table1 Select 1, ' Lee 'INSERT INTO Table1 Select 2, ' Zhang 'INSERT INTO table1 Select 4, ' Wang 'Insert INTO table2 Select 1,90Insert INTO table2 Select 2,100Insert INTO table2 select 3,70such as table-------------------------------------------------Table1 | Table2--------

The combination of Inner Join and Left Join and condition, innerjoin When using relational databases, table join and filtering of result sets are essential query skills. Do you understand their usage? Let's try again. Table creation and initialization: Inner

MySQL learning footprint record 13 -- JOIN table -- inner join... ON learning database join table this section content almost vomit blood, read ON the introduction and Baidu to the content, always feel a blank face ..... maybe I have a poor understanding. But I am a person who won't give up easily. After studying for h

In fact, I also found this problem, However, junevoful has already been detailed. I will add two points: 1. Data in the second table cannot be referenced using exists join, indicating that the condition is met once the data in the second table exists, however, using inner join can reference the data in the second table, which is an internal

20060324034 a20050114 4 2006032404Null null 8 2006032408(The number of affected rows is 5) Result description:After careful observation, we will find that the result of left join is exactly the opposite. This time, it is based on the right table (B) and is filled with null when table A is insufficient. 3. Inner joinThe SQL statement is as follows:Select * from Innerjoin B On a. Aid = B. Bid The result is a

Query the four tables aspnet_membership, aspnet_users, users, and userroles. 1. Do not use inner join for four table join queries Declare @ username nvarchar (100) 2. Join a four-table join query using inner Declare @ username n

Label:There are currently two tables, Sgroup and Sgroupuser, which are associated by Gkey, while the Sgroup table records the group, and the Sgroupuser record is the user in the group, so there is no data in the Sgroupuser. You need to use the left join to get the data: The LINQ syntax is as follows: var sg = ( from the dc.sgroup in dc.sgroupuser on G.gkey equals Gu.gkey into L from in l.defaultifempty ()

Entity class User, Dept. Each user has a dept attribute on the -----------------------------------------------------------Model Class-------------------------------------------------------- ------------------ public class User implements Serializable { /** * Serialization ID ID * / private static final long Serialversionuid = 1L; Private Integer ID; User name private String userName; Password private String password; Private Dept Dept;

The outer join in the query from statement can be simplified in many cases;In the parsing phase, the right outer JOIN operation can be turned into an ode value containing the left JOIN operation, in general, the transition: Right JOIN