sql left join with where clause

Tags: record val not first A20 values error action equalHere is an example analysisTable A records the following:AID Anum1 a200501112 a200501123 a200501134 a200501145 a20050115Table B records the following:BID bname1 20060324012 20060324023 20060324034 20060324048 2006032408Create these two table SQL statements as follows:CREATE TABLE AAID Int (1) auto_increment PRIMARY KEY,Anum Char (20))CREATE TABLE B (BID Int (1) not NULL auto_increment PRIMARY KEY

Label:Here is an example analysisTable A records the following:AID Anum1 a200501112 a200501123 a200501134 a200501145 a20050115Table B records the following:BID bname1 20060324012 20060324023 20060324034 20060324048 2006032408Create these two table SQL statements as follows:CREATE TABLE AAID Int (1) auto_increment PRIMARY KEY,Anum Char (20))CREATE TABLE B (BID Int (1) not NULL auto_increment PRIMARY KEY,Bname Char (20))INSERT into aVALUES (1, ' a200501

Inner join on, left join on, right join on, innerjoin 1. Definition: Inner join: only records with equal join fields in two tables are returned. Left

Left join returns records that include all records in the left table and join fields in the right table.Right join returns records that include all records in the right table and the joined fields in the left table.Inner

Mysql Syntax: left join, right join, inner joinTest TABLE user: www.2cto.com test TABLE password TABLE pwd: www.2cto.com 1. CREATE user TABLE: 1 create table 'user' (2 'id' int (11) not null auto_increment, 3 'name' varchar (255) default NULL, 4 'Password' varchar (255) default NULL, 5 primary key ('id') 6) ENGINE = InnoDB default charset = utf8; 2. CREATE a pwd

left join returns records that include all records in the left table and the equivalent of the junction fields in the right table. The right join returns records that include all records in the right table and the equivalent of the junction fields in the left table inner

A good memory is better than a bad penThere are three kinds of SQL connection: Inner connection, outer connection, cross connection.Inner connection includes: equivalent connection, non-equivalent connection, natural connectionOuter connection includes: Left join (left outer connection), right connection (right outer c

ArticleFrom: http://www.cnblogs.com/c-jquery-linq-sql-net-problem/archive/2011/01/17/LINQ_Inner_Join_Group_Join_Left_Join.html We often use inner join, left join, Cartesian Product, and so on during SQL queries. I don't need to explain the concept of the connection method

Usage of the join keyword in the LINQ query expression: Here I will first create an experiment case: class Customer{ public int CustomerId { get; set; } public string Name { get; set; } public int Age { get; set; }}class Product{ public int ProductId { get; set; } public string Name { get; set; } public string Origin { get; set; }}class Order{ public int OrderId { get; set; } public int CustomerId { get; set; } public List

insufficient are null. 2. Right JoinThe SQL statement is as follows:SELECT * from ARight JOIN BOn a.aid = B.bidThe results are as follows:AID Anum BID bname1 a20050111 1 20060324012 a20050112 2 20060324023 a20050113 3 20060324034 a20050114 4 2006032404NULL NULL 8 2006032408(The number of rows affected is 5 rows) Results show:With a closer look, you will find that the result of the

are being compared, they must have consistent data types.The FROM clause of the SELECT statement can specify the following types of connections:Result set corresponding to the FROM clause keywordCROSSJOINCartesian Product (all possible row pairs)INNERJOINOnly columns in CROSS that meet the connection conditionsLEFTOUTERJOINRows in one table that meet the conditions, and all rows in the other tableRIGHTOUTE

081219 -- Retrieve the public part Select * From t_goods a inner join t_storein BOnA.Gid = B.GID -- All the tables on the right are retrieved, and the tables on the left are matched. Select * From t_goods a right join t_storein BOnA.Gid = B.GID -- Retrieve all tables on the left and matched tables o

Organize the inner join, left JOIN, right join,Two main tables: dept, EMPOne is the department, one is the employee table structure is as follows:These two tables dept is the primary table EMP is the child table, the associated column is deptnodept performance has dataEMP Performance has dataInner

Table AAid Adate1 A12 A23 A3TableBBid Bdate1 B12 B24 B4Two tables A, B connected, to remove fields with the same IDSELECT * from a INNER join B on a.aid = B.bid This is only the matching data is taken out.At this point, the removal is:1 A1 B12 A2 B2Then the left join means:SELECT * from a LEFT

Joins are divided into:INNER JOIN???????????????????????? [INNER JOIN]Outer JOIN???????? (left outer join, right outer join)???????? [Left Join