sql中姓名、性别、学号等数据类型和长度如何写??跪求。 SQL Server中姓名,学号,性别,院系都用什么数据类型...
\u6570\u636e\u5e93\u8bbe\u8ba1\u4e2d\u59d3\u540d\u6027\u522b\u5b66\u53f7\u73ed\u7ea7\u7b49\u7684\u6570\u636e\u7c7b\u578b\u8fd9\u8981\u770b\u4f60\u5b58\u50a8\u7684\u6570\u636e\u7684\u603b\u4f53\u60c5\u51b5\u6765\u770b\uff0c\u4e00\u822c
\u59d3\u540d\uff1avarchar\uff0850\uff09\u8003\u8651\u5c11\u6570\u6c11\u65cf\u4eba\u7684\u540d\u5b57\u7279\u522b\u957f
\u6027\u522b\uff1achar\uff082\uff09\u5982\u679c\u5199\u4e2d\u6587\u7537\u6216\u8005\u5973\uff0c\u4e00\u4e2a\u6c49\u5b57\u662f\u4e24\u4e2a\u5b57\u7b26\uff0c\u6240\u4ee5\u957f\u5ea6\u4e3a2\uff0c\u5982\u679c\u662f\u82f1\u6587F\uff08female\uff09M\uff08male\uff09\u8868\u793a\u90a3\u4e48\u7528char\uff081\uff09\u5c31\u591f\u4e86\uff0c\u5982\u679c\u7528\u5168\u79f0\u90a3\u5c31\u8981\u7528varchar\uff086\uff09\u4e86
\u5b66\u53f7\uff1a\u8981\u770b\u4f60\u8981\u5f55\u5165\u7684\u5b66\u53f7\u5177\u4f53\u6709\u591a\u957f\uff0c\u6bd4\u5982\u6709\u7684\u5b66\u6821\u7684\u5b66\u53f7\u662f2007111222333444\uff0c\u90a3\u5c31\u8981\u8981char\uff0816\uff09\uff0c\u73ed\u7ea7\u4e5f\u4e00\u6837
\u603b\u7684\u6765\u8bf4\u5c31\u8981\u770b\u4f60\u5b9e\u9645\u5b58\u50a8\u7684\u6570\u636e\u8981\u591a\u957f\u624d\u80fd\u77e5\u9053\u8981\u4ec0\u4e48\u6570\u636e\u7c7b\u578b
varchar(几位学号就是长度几);名字嘛就是varchar(15)一般不会超过8个汉字吧;性别如果要是规定好的话(比如只能是‘男’或者‘女’)的话就用定长char(2) check in(‘男’,‘女’),否如果不确定填什么的话,就用varchar(5)。一般不会超过两个汉字吧。
以下是最省空间的方法了:
create table student
(
学号 smallint,
姓名 nvarchar(4),-----------姓名不超过4个汉字
性别 bit ----------------只有男和女两种性别,所以可以用bit型
)
姓名 varchar(20)
性别 varchar(2) -- 男或 女
学号 varchar(30)
或者
姓名 varchar(20)
性别 tinyint(1) -- 1或者0
学号 bigint
给你个示例:
create table student
(
学号 int primary key
姓名 varchar(20),
性别 varchar(5) check (性别 in ('男','女'))
)
这个要看是使用什么数据库的,不同的数据库有些数据类型是不一样的
绛旓細select 瀛﹀彿,濮撳悕,鎬у埆=case when 鎬у埆=鈥樼敺鈥檛hen 'male' else 'female' end from 琛
绛旓細where s.鎬у埆='鐢' order by s.鍑虹敓鏃ユ湡 desc 2锛庝粠瀛︾敓琛ㄥ拰鎴愮哗琛ㄤ袱涓〃涓锛屾绱㈡墍鏈夋垚缁╁浜85鍒鐨勫鍙銆佸鍚嶃佽绋嬪彿銆佸鏈熷拰鎴愮哗銆俿elect s.瀛﹀彿,s.濮撳悕,c.璇剧▼鍙,c.瀛︽湡,c.鎴愮哗 from 瀛︾敓琛 s left join 鎴愮哗琛 c on s.瀛﹀彿=c.瀛﹀彿 where c.鎴愮哗>=85 3锛庣粺璁℃瘡涓笓涓氱殑瀛︾敓浜烘暟...
绛旓細select 鍒楀悕锛瀛﹀彿锛夛紝鍒楀悕锛濮撳悕锛夛紝鍒楀悕锛堝勾榫勶級from table_name where 鍒楀悕锛鎬у埆锛=鐢锋сSQL 鏄竴绉嶈绠楁満璇█锛岀敤鏉ュ瓨鍌ㄣ佹绱㈠拰淇敼鍏崇郴鍨嬫暟鎹簱涓瓨鍌鐨勬暟鎹銆
绛旓細瀛︾敓琛細create table student(stu_no int primary key,stu_name varchar(10),stu_sex varchar(10),stu_class varchar(10),stu_born varchar(10),stu_address varchar(20),stu_remarks varchar(20));insert into student values(1,'鐜嬫槑','鐢','澶氬獟浣061','1987-10-4','鍗椾含','濂');in...
绛旓細create table student (瀛﹀彿 int identity(1,1) not null,濮撳悕 varchar(20) primary key ,骞撮緞 tinyint,)鎴栬 create table student (瀛﹀彿 int identity(1,1) not null primary key,濮撳悕 varchar(20) unique ,骞撮緞 tinyint,)鍏卞悓瀛︿範锛
绛旓細1 select 濮撳悕,骞撮緞 from 瀛︾敓琛 where 鎬у埆 = '鐢'2 select 瀛﹀彿 from 鎴愮哗琛 where 鎴愮哗 < 60 3 select 濮撳悕,璇剧▼鍚,鎴愮哗 from 瀛︾敓琛 inner join 鎴愮哗琛 on 瀛︾敓琛.瀛﹀彿 = 鎴愮哗琛.瀛﹀彿
绛旓細浣犳槸鏍规嵁浠涔堟潯浠舵煡璇㈠憿锛屽鏋滄病鏈夋潯浠鐨璇濓紝鐩存帴鍐檚elect 瀛﹀彿锛屽鍚嶏紝涓撲笟锛屽嚭鐢熸棩鏈 from 琛ㄥ悕杩欐牱鐨勫舰寮忓氨琛屼簡锛佸氨鏄竴鏉℃渶鍩烘湰鐨凷elect璇彞
绛旓細鍒涘缓琛 create table studen ( 瀛﹀彿 varchar(30), 濮撳悕 varchar(20), 鎬у埆 char(1), 韬珮 varchar(10), 韬唤璇佸彿 varchar(18))go 鍒涘缓杩炴帴--鏈夊緢澶氫腑鏂规硶锛屽鏋滀笉鎯硍eb涓厤缃殑璇 SqlConnection conn=new SqlConnection("server=鏈嶅姟鍣紙鏈湴鐢.琛ㄧず锛;database=鏁版嵁搴;uid=sa;...
绛旓細1. select * from 鐮旂┒鐢 where 濮撳悕 like '椹%'2. insert 鐮旂┒鐢(瀛﹀彿,濮撳悕,鎬у埆,鍏ュ鏃ユ湡, 鍏ュ鍒嗘暟) values('201002001','寮犻箯','鐢','2010-9-15',400)3. select * from 鐮旂┒鐢 where 鍏ュ鍒嗘暟<400 order by 鍏ュ鍒嗘暟 desc 4. delete 鐮旂┒鐢 where 濮撳悕='寮犱笁'...
绛旓細select SNO锛孲NAME from S where SSESX='鐢'涓嬮潰鐨浣犳病璐村嚭璇︾粏鐨勮〃缁撴瀯锛屾病浜哄府浣犱簡 娆㈣繋閲囩撼鎴