exec sql left join
select T1.2,T1.3,T1.4,T1.5,T2.2,T3.3,T4.4,T5.5 from T1 left join T2 on T1.2=T2.2 left join T3 on T1.3=T3.3 left join T4 on T1.4=T4.4 left join T5 on T1.5=T5.5 我想查询得结果应该是T1的记录条数 但是是T1的条数×T2×T3。。 这个怎么改呀:o
by RockJack - SQL server - 2007-09-19 10:05:44 阅读（2855） 回复（1）
已知文件1，2，得出文件3 文件1：file1 aaa!111!AA bbb!222!FF ccc!333!EE ddd!444!FEE 文件2：file2 bbb!ab ccc|de 获取文件3：file3 aaa!111!AA! bbb!222!FF!ab ccc!333!EE!de ddd!444!FEE!
表A记录如下：aID aNum1 a200501112 a200501123 a200501134 a200501145 a20050115表B记录如下:bID bName1 20060324012 20060324023 20060324034 20060324048 2006032408 创建这两个表sql语句如下：CREATE TABLE a aID int( 1 ) AUTO_INCREMENT PRIMARY KEY , aNum char( 20 ) ) CREATE TABLE b( bID int(...
Mysql支持下列用于SELECT语句的join句法： table_reference, table_reference table_reference [CROSS] join table_reference table_reference INNER join table_reference table_reference STRAIGHT_join table_reference table_reference left [OUTER] join table_reference ON conditional_expr table_reference left [OUTER] join table_reference USING (column_list) table_reference NATURAL left [OUTER] join table_ref...
mysql> select * from emp; +-------+-------+--------+------+ | empno | ename | deptno | age | +-------+-------+--------+------+ | 1001 | wang | 10 | 20 | | 1002 | ang | 20 | 30 | | 1003 | ng | 10 | 20 | | 1004 | ling | 30 | 40 | | 1004 | dong | 40 | 40 | +-------+-------+--------+------+ 5 rows in set (0.00 sec) mysql> select * from dept; +--------+-----...
本文转自： http://www.wellho.net/archives/2004/12/index.html#000158 Mysql - left join and RIGHT join, INNER join and OUTER join In a database such as Mysql, data is divided into a series of tables (the "why" is beyond what I'm writing today) which are then connected together in SELECT commands to generate the output required. I find when I'm running Mysql training , people often get confused b...
示例表如下： select * from emp; +----+-----------+ | id | name | +----+-----------+ | 1 | Dennis-1 | | 2 | Dennis-2 | | 3 | Dennis-3 | | 4 | Dennis-4 | | 5 | Dennis-5 | | 6 | Dennis-6 | | 7 | Dennis-7 | | 8 | Dennis-8 | | 9 | Dennis-9 | | 10 | Dennis-10 | select * from emp_dept; +---------+--------+----------+ | dept_id | emp_id | emp_name | +---------+--------+----------+...
假设有下面的表和数据： [code] use test; drop table if exists leftjoinTest_QATemplate; create table leftjoinTest_QATemplate (`考核项` varchar(20), `结果` enum('好','差'), `得分` int, primary key (`考核项`, `结果`)) comment '考核项模板'; drop table if exists leftjoinTest_QAResult; create table leftjoinTest_QAResult (`姓名` varchar(10), `考核项` varchar(20), `结果` enum('好','差'), primary key (`姓...
excel中使用导入excel外部数据，从多个excel工作表中查询数据（见：经验交流：excel中多表格sql查询 ）： select * from `表1$` a,`表2$` b where a.`aaa`=b.`a2` 如何使用left join？ 我试了： select * from `表1$` a , outer `表2$` b where a.`aaa`=b.`a2` 或 select * from `表1$` a left join `表2$` b where a.`aaa`=b.`a2` 语法不通过 select * from `表1$` a full join `表2$` b where a.`aaa`=b.`a2` 提示数据库无法打...
