sql server基本语句

–选择数据库
–use ywh_database
///////测试表里有age name height id 4列
–查找表中全部数据
–select * from student
–查找表中某些列的值
–select name,id from student
–返回唯一不同的值,列和列可以进行组合,如name,id，但此时name和id是看作一个整体的
–select distinct name,id from student
–select distinct name from student
–有条件的从表中选取数据
–select name from student where name=‘cmr’
–select name from student where age<>12 – <>是不等于符号
–select name from student where age>=10
–select name from student where age between 10 and 13
–select * from student where name=‘ywh’ and age>10
–select * from student where name=‘ywh’ or age>10
–select * from student where (name=‘ywh’ or age>10) and id=2000
–对结果进行排序,默认升序
–select * from student order by age
–有多列时，按照查找时给定的顺序进行排序，若前面的列存在重复值，后面的列可以按照自己给定的方式排序
–elect name,id from student order by name desc,id asc
–插入元素,可以指定列，未给定值的列将被初始化为默认值
–insert into student values (10,‘yyl’,124,2004)
–insert into student(name,id) values (‘yhl’,2005)
–修改表中数据
–update student set age =16,height=170 where name=‘yhl’
–删除表中的某一行,删除所有行但不删除表
–delete from student where name=‘ywh’
–delete from student
–top子句用于规定要返回的记录的数目。
–select top 2 * from student where id>5 --返回前2条查询命令
–select top 50 percent name from student
–like 操作符用于在 WHERE 子句中搜索列中的指定模式
–select * from student where name like ‘%e’ --以e结尾的名字
–select * from student where name not like ‘e%’ --不是以e开始的名字
–通配符
– %代表任意字符， -代表一个字符 [charlist] 字符列表中的任意单一字符 [^charlist]/[!charlist] 不在字符列表中的任意单一字符
–select * from student where name like ‘a%’
–select * from student where name like ‘a__’
–select * from student where name like ‘[abcdefg]%’
–select * from student where name like ‘[^edc]%’ --我用[!edc]查出来不对，版本是2014
–in操作
–select * from student where id in(1,2,3,4)
–select into 语句从一个表中选取数据，然后把数据插入另一个表中
–select * into student3 from student where id>5
–删除表
–drop table student2
–删除表中的内容但不删除表
–truncate table student3
–alter语句用于在已有的表中添加、修改或删除列。
–alter table student3 add birthday date
–alter table student3 drop column birthday
–alter table student3 add birthday date
–alter table student3 alter column birthday datetime