摘要：
left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记录right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录inner join(等值连接) 只返回两个表中联结字段相等的行举例如下： -------------------------------------------- 表A记录如下： aID aNum 1 a20050111 2 a20050112 3 a20050113 4 a20050114 5 a20050115 表B记录如下: bID bName 1 2006032401 2 2006032402 3 2006032403 4 阅读全文
摘要：
Stored Procedures and triggers within a database are similar constructs. They can both perform the same SQL statements. The biggest difference between the two is how they are executed. A stored procedure has to be executed by a user, while a trigger is executed by the system as the result of an even 阅读全文