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数据库编译中的As和on代表啥

SQL数据库中SELECT AS中的AS代表的是重命名列名或者表名。 其用法是 SELECT 列名1 AS 列1,列名2 AS 列1 FROM 表1 语句表示的意思是从表1中读取列名1和列名2的数据,并且为列名1和列名2分别重命名为列1和列2.

Inner join 内连接 as 别名 on 之后跟内连接的条件 这句话应该是: SELECT column_name(s) FROM table_name1 INNER JOIN table_name2 AS t2 (别名) ON table_name1.column_name=t2.column_name

hear from sb 的意思就是指“收到某人的来信”先排除掉; hear about 是听说; hear of 有听说的意思,也有允许,听从的意思 hear和to放在一起是不对的,这两个词表示的方向相反,排除掉。 ……on subject?你确定你没抄错吗? hear about和hear of ...

1、as a whole 整体来看; 普遍说来, 一般地说 例句: Is this true just in this country, or in the world as a whole? 只是在这个国家如此呢,还是就整个世界来看都这样? 2、on the whole 大体上,基本上,总的来看[说]; 大抵; 大致如此; 大...

join on 就是表连接. select * from table1 as t1 join table2 as t2 on(t1.a= t2.b) where t1.c = x order by t1.d desc; 等价于 select * from table 1 as t1 ,table2 as t2 where t1.a = t2.b and t1.c = x order by t1.d desc; 2个SQL语句对...

http://wenku.baidu.com/view/a3f522106edb6f1aff001fcc.html oracle 的正则表达式

upon是“接近,在上面”的意思,是介词, on 和opon一样,as soon as是“一···就”的意思是连词 on和upon是后面加doing或名词 as soon as 后面加句子,不能加单个词 as soon as 和upon 区别 as soon as 和upon 的区别是: as soon as 尽快 / 立即 / 马上 ...

没有显示错误就是说明程序正常执行完了,也许你的程序里并没有在控制台打印东西的语句,类似System.out.println("some thing");

1 select classname ,manager ,studentname,birthdate,idcard from classinfo join studentinfo on classinfo.classid=studentinfo.classid where classinfo.classid=15 order by studentinfo.birthdate DESC 2 select classname,count(studenti...

according as 根据,随……而定(后接从句); 如:Everyone contributes according as he is able.每个人根据自己的能力作出贡献. in proportion as 按…比例,依…程度而变; 如:Each of these traits, in proportion as it reinforces the chosen be...

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