(一个SQL数据库的简单问题）
\u4e00\u4e2aSQL\u6570\u636e\u5e93\u7684\u7b80\u5355\u95ee\u9898\u524d\u9762\u7684\u7b54\u6848\u6b63\u786e\uff0c\u4e0d\u80fd\u6700\u540e\u90a3\u6837\u5199\uff0c\u8fd9\u662f\u89c4\u5b9a\u7684\u3002
column \u7684\u610f\u601d\u662f\u5217\u3002
1 \u7565
2 \u7565
3 insert into BookInfo (BookId,BookName,Publish,Author) values ('001','\u8fd9\u672c\u4e66\u662f\u4ec0\u4e48\u4e66','\u65e0\u77e5\u8005\u65e0\u754f\u51fa\u7248\u793e',\u2018\u65e0\u540d\u6c0f')
4 Delete from BookInfo where BookName='\u67e5\u65e0\u6b64\u4e66'
5 Update ReaderInfo set Institute=\u2018\u8ba1\u7b97\u673a\u5b66\u9662' where ReadId=1
6 select * from ReadInfo where left(grade,4)='2012'
7 create view vw_myview1
as
select a.ReadId,c.BookName,b.LentDate,b.ReturnDate from ReaderInfo a
left join ReaderBook b
on a.ReaderId=b.ReadId
left join BookInfo c
on b.BookId=c.BookId
where a.deleamark=0 and b.returnSign=0
8 create procedure DropD
as
Drop Database Library
二、一般情况下，对于姓名、性别这样的字段，没有使用VARCHAR的必要，就用CHAR就可以，而对于家庭地址这样的字段，使用VARCHAR可以大大节省存储空间。
三、对于一个表，如果有一个字段是VARCHAR，那么所有的CHAR类型字段，实际上都是按照VARCHAR处理的。
用varchar(8)如果输入的没有8个字符。占用的空间只有你输入的字符宽度大小
而char(8)如果输入的只有5个字符。自动会用空格补到8个字符的大小,这样就会造成你取值的时候出错。一定要加空格才会匹配
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