--select

select * from student;

--all 查询所有

select all sex from student;

--distinct 过滤重复

select distinct sex from student;

--count 统计

select count(*) from student;

select count(sex) from student;

select count(distinct sex) from student;

--top 取前N条记录

select top 3 * from student;

--alias column name 列重命名

select id as 编号, name \'名称\', sex 性别 from student;

--alias table name 表重命名

select id, name, s.id, s.name from student s;

--column 列运算

select (age + id) col from student;

select s.name + \'-\' + c.name from classes c, student s where s.cid = c.id;

--where 条件

select * from student where id = 2;

select * from student where id > 7;

select * from student where id < 3;

select * from student where id <> 3;

select * from student where id >= 3;

select * from student where id <= 5;

select * from student where id !> 3;

select * from student where id !< 5;

--and 并且

select * from student where id > 2 and sex = 1;

--or 或者

select * from student where id = 2 or sex = 1;

--between ... and ... 相当于并且

select * from student where id between 2 and 5;

select * from student where id not between 2 and 5;

--like 模糊查询

select * from student where name like  \'%a%\';

select * from student where name like  \'%[a][o]%\';

select * from student where name not like  \'%a%\';

select * from student where name like \'ja%\';

select * from student where name not like \'%[j,n]%\';

select * from student where name like \'%[j,n,a]%\';

select * from student where name like \'%[^ja,as,on]%\';

select * from student where name like \'%[ja_on]%\';

--in 子查询

select * from student where id in (1, 2);

--not in 不在其中

select * from student where id not in (1, 2);

--is null 是空

select * from student where age is null;

--is not null 不为空

select * from student where age is not null;

--order by 排序

select * from student order by name;

select * from student order by name desc;

select * from student order by name asc;

--group by 分组

按照年龄进行分组统计

select count(age), age from student group by age;

按照性别进行分组统计

select count(*), sex from student group by sex;

按照年龄和性别组合分组统计，并排序

select count(*), sex from student group by sex, age order by age;

按照性别分组，并且是id大于2的记录最后按照性别排序

select count(*), sex from student where id > 2 group by sex order by sex;

查询id大于2的数据，并完成运算后的结果进行分组和排序

select count(*), (sex * id) new from student where id > 2 group by sex * id order by sex * id;

--group by all 所有分组

按照年龄分组，是所有的年龄

select count(*), age from student group by all age;

--having 分组过滤条件

按照年龄分组，过滤年龄为空的数据，并且统计分组的条数和现实年龄信息

select count(*), age from student group by age having age is not null;

按照年龄和cid组合分组，过滤条件是cid大于1的记录

select count(*), cid, sex from student group by cid, sex having cid > 1;

按照年龄分组，过滤条件是分组后的记录条数大于等于2

select count(*), age from student group by age having count(age) >= 2;

按照cid和性别组合分组，过滤条件是cid大于1，cid的最大值大于2

select count(*), cid, sex from student group by cid, sex having cid > 1 and max(cid) > 2;

将一个table的查询结果当做一个新表进行查询

select * from (

    select id, name from student where sex = 1

) t where t.id > 2;

查询班级信息，统计班级学生人生

select *, (select count(*) from student where cid = classes.id) as num 

from classes order by num;

查询班级id大于小于的这些班级的学生信息

select * from student where cid in (

    select id from classes where id > 2 and id < 4

);

查询不是班的学生信息

select * from student where cid not in (

    select id from classes where name = \'2班\'

)

查询存在班级id为的学生信息

select * from student where exists (

    select * from classes where id = student.cid and id = 3

);

查询没有分配班级的学生信息

select * from student where not exists (

    select * from classes where id = student.cid

);

查询班级的学生年龄大于班级的学生的年龄的信息

select * from student where cid = 5 and age > all (

    select age from student where cid = 3

);

select * from student where cid = 5 and age > any (

    select age from student where cid = 3

);

select * from student where cid = 5 and age > some (

    select age from student where cid = 3

);

select distinct sex from student;

select count(sex), count(distinct sex) from student;

对年龄大于的进行汇总

select age from student 

where age > 20 order by age compute sum(age) by age;

对年龄大于的按照性别进行分组汇总年龄信息

select id, sex, age from student 

where age > 20 order by sex, age compute sum(age) by sex;

按照年龄分组汇总

select age from student 

where age > 20 order by age, id compute sum(age);

按照年龄分组，年龄汇总，id找最大值

select id, age from student 

where age > 20 order by age compute sum(age), max(id);

select count(*), sex from student group by sex with cube;

select count(*), age, sum(age) from student where age is not null group by age with cube;

排序函数 over([分组语句] 排序子句[desc][asc])

排序子句 order by 列名, 列名

分组子句 partition by 分组列, 分组列

按照名称排序的顺序递增

select s.id, s.name, cid, c.name, row_number() over(order by c.name) as number 

from student s, classes c where cid = c.id;

顺序递增

select id, name, rank() over(order by cid) as rank from student;

跳过相同递增

select s.id, s.name, cid, c.name, rank() over(order by c.name) as rank 

from student s, classes c where cid = c.id;

不跳过，直接递增

select s.id, s.name, cid, c.name, dense_rank() over(order by c.name) as dense 

from student s, classes c where cid = c.id;

利用partition by按照班级名称分组，学生id排序

select s.id, s.name, cid, c.name, row_number() over(partition by c.name order by s.id) as rank 

from student s, classes c where cid = c.id;

select s.id, s.name, cid, c.name, rank() over(partition by c.name order by s.id) as rank 

from student s, classes c where cid = c.id;

select s.id, s.name, cid, c.name, dense_rank() over(partition by c.name order by s.id) as rank 

from student s, classes c where cid = c.id;

select s.id, s.name, cid, c.name, 

ntile(5) over(order by c.name) as ntile 

from student s, classes c where cid = c.id;

--union 并集、不重复

select id, name from student where name like \'ja%\'

union

select id, name from student where id = 4;

--并集、重复

select * from student where name like \'ja%\'

union all

select * from student;

--交集（相同部分）

select * from student where name like \'ja%\'

intersect

select * from student;

--减集（除相同部分）

select * from student where name like \'ja%\'

except

select * from student where name like \'jas%\';

--表达式

with statNum(id, num) as 

(

    select cid, count(*) 

    from student 

    where id > 0

    group by cid

)

select id, num from statNum order by id;

with statNum(id, num) as 

(

    select cid, count(*) 

    from student 

    where id > 0

    group by cid

)

select max(id), avg(num) from statNum;

--简化联接查询

select s.id, s.name, c.id, c.name from student s, classes c where s.cid = c.id;

--左连接

select s.id, s.name, c.id, c.name from student s left join classes c on s.cid = c.id;

--右连接

select s.id, s.name, c.id, c.name from student s right join classes c on s.cid = c.id;

--内连接

select s.id, s.name, c.id, c.name from student s inner join classes c on s.cid = c.id;

--inner可以省略

select s.id, s.name, c.id, c.name from student s join classes c on s.cid = c.id;

--交叉联接查询，结果是一个笛卡儿乘积

select s.id, s.name, c.id, c.name from student s cross join classes c

--where s.cid = c.id;

--自连接

select distinct s.* from student s, student s1 where s.id <> s1.id and s.sex = s1.sex;

select 

    max(age) max_age, 

    min(age) min_age, 

    count(age) count_age, 

    avg(age) avg_age, 

    sum(age) sum_age, 

    var(age) var_age 

from student;

select dateAdd(day, 3, getDate());--加天

select dateAdd(year, 3, getDate());--加年

select dateAdd(hour, 3, getDate());--加小时

--返回跨两个指定日期的日期边界数和时间边界数

select dateDiff(day, \'2011-06-20\', getDate());

--相差秒数

select dateDiff(second, \'2011-06-22 11:00:00\', getDate());

--相差小时数

select dateDiff(hour, \'2011-06-22 10:00:00\', getDate());

select dateName(month, getDate());--当前月份

select dateName(minute, getDate());--当前分钟

select dateName(weekday, getDate());--当前星期

select datePart(month, getDate());--当前月份

select datePart(weekday, getDate());--当前星期

select datePart(second, getDate());--当前秒数

select day(getDate());--返回当前日期天数

select day(\'2011-06-30\');--返回当前日期天数

select month(getDate());--返回当前日期月份

select month(\'2011-11-10\');

select year(getDate());--返回当前日期年份

select year(\'2010-11-10\');

select getDate();--当前系统日期

select getUTCDate();--utc日期

select pi();--PI函数

select rand(100), rand(50), rand(), rand();--随机数

select round(rand(), 3), round(rand(100), 5);--精确小数位

--精确位数，负数表示小数点前

select round(123.456, 2), round(254.124, -2);

select round(123.4567, 1, 2);

select col_name(object_id(\'student\'), 1);--返回列名

select col_name(object_id(\'student\'), 2);

--该列数据类型长度

select col_length(\'student\', col_name(object_id(\'student\'), 2)); 

--该列数据类型长度

select col_length(\'student\', col_name(object_id(\'student\'), 1)); 

--返回类型名称、类型id

select type_name(type_id(\'varchar\')), type_id(\'varchar\');

--返回列类型长度

select columnProperty(object_id(\'student\'), \'name\', \'PRECISION\');

--返回列所在索引位置

select columnProperty(object_id(\'student\'), \'sex\', \'ColumnId\');

select ascii(\'a\');--字符转换ascii值

select ascii(\'A\');

select char(97);--ascii值转换字符

select char(65);

select nchar(65);

select nchar(45231);

select nchar(32993);--unicode转换字符

select unicode(\'A\'), unicode(\'中\');--返回unicode编码值

select soundex(\'hello\'), soundex(\'world\'), soundex(\'word\');

select patindex(\'%a\', \'ta\'), patindex(\'%ac%\', \'jack\'), patindex(\'dex%\', \'dexjack\');--匹配字符索引

select \'a\' + space(2) + \'b\', \'c\' + space(5) + \'d\';--输出空格

select charIndex(\'o\', \'hello world\');--查找索引

select charIndex(\'o\', \'hello world\', 6);--查找索引

select quoteName(\'abc[]def\'), quoteName(\'123]45\');

--精确数字

select str(123.456, 2), str(123.456, 3), str(123.456, 4);

select str(123.456, 9, 2), str(123.456, 9, 3), str(123.456, 6, 1), str(123.456, 9, 6);

select difference(\'hello\', \'helloWorld\');--比较字符串相同

select difference(\'hello\', \'world\');

select difference(\'hello\', \'llo\');

select difference(\'hello\', \'hel\');

select difference(\'hello\', \'hello\');

select replace(\'abcedef\', \'e\', \'E\');--替换字符串

select stuff(\'hello world\', 3, 4, \'ABC\');--指定位置替换字符串

select replicate(\'abc#\', 3);--重复字符串

select subString(\'abc\', 1, 1), subString(\'abc\', 1, 2), subString(\'hello Wrold\', 7, 5);--截取字符串

select len(\'abc\');--返回长度

select reverse(\'sqlServer\');--反转字符串

select left(\'leftString\', 4);--取左边字符串

select left(\'leftString\', 7);

select right(\'leftString\', 6);--取右边字符串

select right(\'leftString\', 3);

select lower(\'aBc\'), lower(\'ABC\');--小写

select upper(\'aBc\'), upper(\'abc\');--大写

--去掉左边空格

select ltrim(\' abc\'), ltrim(\'# abc#\'), ltrim(\'  abc\');

--去掉右边空格

select rtrim(\' abc    \'), rtrim(\'# abc#   \'), rtrim(\'abc\');

select current_user;

select user;

select user_id(), user_id(\'dbo\'), user_id(\'public\'), user_id(\'guest\');

select user_name(), user_name(1), user_name(0), user_name(2);

select session_user;

select suser_id(\'sa\');

select suser_sid(), suser_sid(\'sa\'), suser_sid(\'sysadmin\'), suser_sid(\'serveradmin\');

select is_member(\'dbo\'), is_member(\'public\');

select suser_name(), suser_name(1), suser_name(2), suser_name(3);

select suser_sname(), suser_sname(0x01), suser_sname(0x02), suser_sname(0x03);

select is_srvRoleMember(\'sysadmin\'), is_srvRoleMember(\'serveradmin\');

select permissions(object_id(\'student\'));

select system_user;

select schema_id(), schema_id(\'dbo\'), schema_id(\'guest\');

select schema_name(), schema_name(1), schema_name(2), schema_name(3);

select app_name();--当前会话的应用程序名称

select cast(2011 as datetime), cast(\'10\' as money), cast(\'0\' as varbinary);--类型转换

select convert(datetime, \'2011\');--类型转换

select coalesce(null, \'a\'), coalesce(\'123\', \'a\');--返回其参数中第一个非空表达式

select collationProperty(\'Traditional_Spanish_CS_AS_KS_WS\', \'CodePage\');

select current_timestamp;--当前时间戳

select current_user;

select isDate(getDate()), isDate(\'abc\'), isNumeric(1), isNumeric(\'a\');

select dataLength(\'abc\');

select host_id();

select host_name();

select db_name();

select ident_current(\'student\'), ident_current(\'classes\');--返回主键id的最大值

select ident_incr(\'student\'), ident_incr(\'classes\');--id的增量值

select ident_seed(\'student\'), ident_seed(\'classes\');

select @@identity;--最后一次自增的值

select identity(int, 1, 1) as id into tab from student;--将studeng表的烈属，以/1自增形式创建一个tab

select * from tab;

select @@rowcount;--影响行数

select @@cursor_rows;--返回连接上打开的游标的当前限定行的数目

select @@error;--T-SQL的错误号

select @@procid;

set datefirst 7;--设置每周的第一天，表示周日

select @@datefirst as \'星期的第一天\', datepart(dw, getDate()) AS \'今天是星期\';

select @@dbts;--返回当前数据库唯一时间戳

set language \'Italian\';

select @@langId as \'Language ID\';--返回语言id

select @@language as \'Language Name\';--返回当前语言名称

select @@lock_timeout;--返回当前会话的当前锁定超时设置（毫秒）

select @@max_connections;--返回SQL Server 实例允许同时进行的最大用户连接数

select @@MAX_PRECISION AS \'Max Precision\';--返回decimal 和numeric 数据类型所用的精度级别

select @@SERVERNAME;--SQL Server 的本地服务器的名称

select @@SERVICENAME;--服务名

select @@SPID;--当前会话进程id

select @@textSize;

select @@version;--当前数据库版本信息

select @@CONNECTIONS;--连接数

select @@PACK_RECEIVED;

select @@CPU_BUSY;

select @@PACK_SENT;

select @@TIMETICKS;

select @@IDLE;

select @@TOTAL_ERRORS;

select @@IO_BUSY;

select @@TOTAL_READ;--读取磁盘次数

select @@PACKET_ERRORS;--发生的网络数据包错误数

select @@TOTAL_WRITE;--sqlserver执行的磁盘写入次数

select patIndex(\'%soft%\', \'microsoft SqlServer\');

select patIndex(\'soft%\', \'software SqlServer\');

select patIndex(\'%soft\', \'SqlServer microsoft\');

select patIndex(\'%so_gr%\', \'Jsonisprogram\');

--查询所有已创建函数

select definition,* from sys.sql_modules m join sys.objects o on m.object_id = o.object_id

and type in(\'fn\', \'if\', \'tf\');

if (object_id(\'fun_add\', \'fn\') is not null)

    drop function fun_add

go

create function fun_add(@num1 int, @num2 int)

    returns int

with execute as caller

as

    begin

        declare @result int;

        if (@num1 is null)

            set @num1 = 0;

        if (@num2 is null)

            set @num2 = 0;

        set @result = @num1 + @num2;

        return @result;

    end

go

调用函数

select dbo.fun_add(id, age) from student;

--自定义函数，字符串连接

if (object_id(\'fun_append\', \'fn\') is not null)

    drop function fun_append

go

create function fun_append(@args nvarchar(1024), @args2 nvarchar(1024))

    returns nvarchar(2048)

as

    begin

        return @args + @args2;

    end

go

select dbo.fun_append(name, \'abc\') from student;

alter function fun_append(@args nvarchar(1024), @args2 nvarchar(1024))

    returns nvarchar(1024)

as

    begin

        declare @result varchar(1024);    

        --coalesce返回第一个不为null的值    

        set @args = coalesce(@args, \'\');

        set @args2 = coalesce(@args2, \'\');;

        set @result = @args + @args2;

        return @result;

    end

go

select dbo.fun_append(name, \'#abc\') from student;

--返回table对象函数

select name, object_id, type from sys.objects where type in (\'fn\', \'if\', \'tf\') or type like \'%f%\';

if (exists (select * from sys.objects where type in (\'fn\', \'if\', \'tf\') and name = \'fun_find_stuRecord\'))

    drop function fun_find_stuRecord

go

create function fun_find_stuRecord(@id int)

    returns table

as

    return (select * from student where id = @id);

go

select * from dbo.fun_find_stuRecord(2);