高考问答关于孙悟空的新电影:SQL语句的问题,谁来帮我看看
来源：百度文库 编辑：高考问答 时间：2024/05/10 09:13:33
SQL="SELECT Class.ID,Class.Class,Class.Orders,Class.Orders AS corder,NClass.ID AS
NClassID,NClass.NClass,NClass.ParentID,NClass.Orders AS norder FROM "& TableClass &" Class LEFT JOIN "& TableNClass &" NClass
ON NClass.ParentID=Class.ID ORDER BY Class.Orders,NClass.Orders"
里边的Class.Orders AS corder这句是什么意思?
FROM "& TableClass &" Class LEFT JOIN "& TableNClass &" NClass ON NClass.ParentID=Class.ID
这句又是什么意思
有些看不懂!~
NClassID,NClass.NClass,NClass.ParentID,NClass.Orders AS norder FROM "& TableClass &" Class LEFT JOIN "& TableNClass &" NClass
ON NClass.ParentID=Class.ID ORDER BY Class.Orders,NClass.Orders"
里边的Class.Orders AS corder这句是什么意思?
FROM "& TableClass &" Class LEFT JOIN "& TableNClass &" NClass ON NClass.ParentID=Class.ID
这句又是什么意思
有些看不懂!~
Class.Orders AS corder 是在输出结果的时候把Class表的Orders列作为corder列输出
FROM "& TableClass &" Class LEFT JOIN "& TableNClass &" NClass ON NClass.ParentID=Class.ID
是表示数据从Class表和NClass表中获得，而且以NClass.ParentID=Class.ID为条件两个表内联
自己动手建立一个模拟数据库，建立两个表，加些纪录试验一下就会明白
Class.Orders AS corder做为一个新表处理
下面的是外链接