• sql中的字符串匹配、函数大全


    1.语法基础

    http://www.jianshu.com/p/d8cf42a96cd5

    2.高级语法编程

    http://www.imooc.com/article/1415

    3.高级查询

    http://www.cnblogs.com/hoojo/archive/2011/07/16/2108129.html

    高级查询在数据库中用得是最频繁的,也是应用最广泛的。
    
    Ø 基本常用查询
    
    --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;
    Ø 嵌套子查询
    
        子查询是一个嵌套在select、insert、update或delete语句或其他子查询中的查询。任何允许使用表达式的地方都可以使用子查询。子查询也称为内部查询或内部选择,而包含子查询的语句也成为外部查询或外部选择。
    
     
    
    # from (selecttable)示例
    
    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;
    上面括号中的语句,就是子查询语句(内部查询)。在外面的是外部查询,其中外部查询可以包含以下语句:
    
         1、 包含常规选择列表组件的常规select查询
    
         2、 包含一个或多个表或视图名称的常规from语句
    
         3、 可选的where子句
    
         4、 可选的group by子句
    
         5、 可选的having子句
    
     
    
    # 示例
    
    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;
     
    
    # in, not in子句查询示例
    
    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'
    )
    innot in 后面的子句返回的结果必须是一列,这一列的结果将会作为查询条件对应前面的条件。如cid对应子句的id;
    
     
    
    # exists和not exists子句查询示例
    
    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
    );
    exists和not exists查询需要内部查询和外部查询进行一个关联的条件,如果没有这个条件将是查询到的所有信息。如:id等于student.id;
    
     
    
    # someany、all子句查询示例
    
    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
    );
     
    
    Ø 聚合查询
    
    1、 distinct去掉重复数据
    
    select distinct sex from student;
    select count(sex), count(distinct sex) from student;
     
    
    2、 compute和compute by汇总查询
    
    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);
    compute进行汇总前面是查询的结果,后面一条结果集就是汇总的信息。compute子句中可以添加多个汇总表达式,可以添加的信息如下:
    
         a、 可选by关键字。它是每一列计算指定的行聚合
    
         b、 行聚合函数名称。包括sum、avgminmax、count等
    
         c、 要对其执行聚合函数的列
    
         compute by适合做先分组后汇总的业务。compute by后面的列一定要是order by中出现的列。
    
     
    
    3、 cube汇总
    
    cube汇总和compute效果类似,但语法较简洁,而且返回的是一个结果集。
    
    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;
    cube要结合group by语句完成分组汇总
    
     
    
    Ø 排序函数
    
       排序在很多地方需要用到,需要对查询结果进行排序并且给出序号。比如:
    
       1、 对某张表进行排序,序号需要递增不重复的
    
       2、 对学生的成绩进行排序,得出名次,名次可以并列,但名次的序号是连续递增的
    
       3、 在某些排序的情况下,需要跳空序号,虽然是并列
    
    基本语法
    
    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
     
    
    # row_number函数
    
    根据排序子句给出递增连续序号
    
    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;
     
    
    # rank函数函数
    
    根据排序子句给出递增的序号,但是存在并列并且跳空
    
    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;
     
    
    # dense_rank函数
    
    根据排序子句给出递增的序号,但是存在并列不跳空
    
    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;
     
    
    # partition by分组子句
    
    可以完成对分组的数据进行增加排序,partition by可以与以上三个函数联合使用。
    
    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;
     
    
    # ntile平均排序函数
    
    将要排序的数据进行平分,然后按照等分排序。ntile中的参数代表分成多少等分。
    
    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;
     
    
    Ø 集合运算
    
    操作两组查询结果,进行交集、并集、减集运算
    
    1、 union和union all进行并集运算
    
    --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;
     
    
    2、 intersect进行交集运算
    
    --交集(相同部分)
    select * from student where name like 'ja%'
    intersect
    select * from student;
     
    
    3、 except进行减集运算
    
    --减集(除相同部分)
    select * from student where name like 'ja%'
    except
    select * from student where name like 'jas%';
     
    
    Ø 公式表表达式
    
    查询表的时候,有时候中间表需要重复使用,这些子查询被重复查询调用,不但效率低,而且可读性低,不利于理解。那么公式表表达式可以解决这个问题。
    
    我们可以将公式表表达式(CET)视为临时结果集,在select、insertupdate、delete或是create view语句的执行范围内进行定义。
    
    --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;
     
    
    Ø 连接查询
    
    1、 简化连接查询
    
    --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;
     
    
    2left join左连接
    
    --左连接
    select s.id, s.name, c.id, c.name from student s left join classes c on s.cid = c.id;
     
    
    3right join右连接
    
    --右连接
    select s.id, s.name, c.id, c.name from student s right join classes c on s.cid = c.id;
     
    
    4inner join内连接
    
    --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;
     
    
    5cross join交叉连接
    
    --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;
     
    
    6、 自连接(同一张表进行连接查询)
    
    --自连接
    select distinct s.* from student s, student s1 where s.id <> s1.id and s.sex = s1.sex;
     
    
    Ø 函数
    
    1、 聚合函数
    
    max最大值、min最小值、count统计、avg平均值、sum求和、var求方差
    
    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;
     
    
    2、 日期时间函数
    
    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
     
    
    3、 数学函数
    
    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);
     
    
    4、 元数据
    
    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');
     
    
    5、 字符串函数
    
    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('');--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');
     
    
    6、 安全函数
    
    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);
     
    
    7、 系统函数
    
    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;
     
    
    8、 配置函数
    
    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
     
    
    9、 系统统计函数
    
    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');
     
    
    10、 用户自定义函数
    
    # 查看当前数据库所有函数
    
    --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');
     
    
    # 创建函数
    
    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;
     
    
    # 修改函数
    
    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类型函数
    
    --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);
    View Code

    4.时间转换

     1 SELECT CONVERT(varchar(100), GETDATE(), 0) 05  9 2011  9:12AM
     2  SELECT CONVERT(varchar(100), GETDATE(), 1) 05/09/11
     3 SELECT CONVERT(varchar(100), GETDATE(), 2) 11.05.09
     4 SELECT CONVERT(varchar(100), GETDATE(), 3) 09/05/11
     5 SELECT CONVERT(varchar(100), GETDATE(), 4) 09.05.11
     6 SELECT CONVERT(varchar(100), GETDATE(), 5) 09-05-11
     7 SELECT CONVERT(varchar(100), GETDATE(), 6) 09 05 11
     8 SELECT CONVERT(varchar(100), GETDATE(), 7) 05 09, 11
     9 SELECT CONVERT(varchar(100), GETDATE(), 8) 09:13:14
    10 SELECT CONVERT(varchar(100), GETDATE(), 9) 05  9 2011  9:13:14:670AM
    11 SELECT CONVERT(varchar(100), GETDATE(), 10) 05-09-11
    12 SELECT CONVERT(varchar(100), GETDATE(), 11) 11/05/09
    13 SELECT CONVERT(varchar(100), GETDATE(), 12) 110509
    14 SELECT CONVERT(varchar(100), GETDATE(), 13) 09 05 2011 09:13:14:670
    15 SELECT CONVERT(varchar(100), GETDATE(), 14) 09:13:14:670
    16 SELECT CONVERT(varchar(100), GETDATE(), 20) 2011-05-09 09:13:14
    17 SELECT CONVERT(varchar(100), GETDATE(), 21) 2011-05-09 09:13:14.670
    18 SELECT CONVERT(varchar(100), GETDATE(), 22) 05/09/11  9:15:33 AM
    19 SELECT CONVERT(varchar(100), GETDATE(), 23) 2011-05-09
    20 SELECT CONVERT(varchar(100), GETDATE(), 24) 09:15:33
    21 SELECT CONVERT(varchar(100), GETDATE(), 25) 2011-05-09 09:15:33.140
    22 SELECT CONVERT(varchar(100), GETDATE(), 100) 05  9 2011  9:15AM
    23 SELECT CONVERT(varchar(100), GETDATE(), 101) 05/09/2011
    24 SELECT CONVERT(varchar(100), GETDATE(), 102) 2011.05.09
    25 SELECT CONVERT(varchar(100), GETDATE(), 103) 09/05/2011
    26 SELECT CONVERT(varchar(100), GETDATE(), 104) 09.05.2011
    27 SELECT CONVERT(varchar(100), GETDATE(), 105) 09-05-2011
    28 SELECT CONVERT(varchar(100), GETDATE(), 106) 09 05 2011
    29 SELECT CONVERT(varchar(100), GETDATE(), 107) 05 09, 2011
    30 SELECT CONVERT(varchar(100), GETDATE(), 108) 09:16:38
    31 SELECT CONVERT(varchar(100), GETDATE(), 109) 05  9 2011  9:16:38:543AM
    32 SELECT CONVERT(varchar(100), GETDATE(), 110) 05-09-2011
    33 SELECT CONVERT(varchar(100), GETDATE(), 111) 2011/05/09
    34 SELECT CONVERT(varchar(100), GETDATE(), 112) 20110509
    35 SELECT CONVERT(varchar(100), GETDATE(), 113) 09 05 2011 09:17:19:857
    36 SELECT CONVERT(varchar(100), GETDATE(), 114) 09:17:19:857
    37 SELECT CONVERT(varchar(100), GETDATE(), 120) 2011-05-09 09:17:19
    38 SELECT CONVERT(varchar(100), GETDATE(), 121) 2011-05-09 09:17:19.857
    39 SELECT CONVERT(varchar(100), GETDATE(), 126) 2011-05-09T09:17:19.857
    40 SELECT CONVERT(varchar(100), GETDATE(), 130)  6 ????? ??????? 1432  9:17:19:857AM
    41 SELECT CONVERT(varchar(100), GETDATE(), 131)  6/06/1432  9:17:19:857AM
    View Code

    5.数据分页

     1 select * from
     2 
     3 (select ROW_NUMBER() over (order by name ) as num,
     4     Name,
     5     Age,
     6     Sex    
     7 from dt_People) as t
     8 
     9 where t.num>=2
    10 and t.num<4
    View Code

    6.高级语法

    1.按class分组,分组后的结果按照name,age排序,如此根据rn可以进行数据筛选(例如取出年纪最大的)

    1  row_number() over(partition by Class order by name,age desc) rn

     2.生成连续的日期

    注:生成的时间,可以通过convert方法转换为标准的日期格式

     1 --方法1:从当前日期往回显示70天
     2 select dateadd(d, number, GETDATE() + 1 - 70) as every_time
     3 FROM master..spt_values n
     4 WHERE n.type = 'p'
     5 AND n.number <= 70;
     6 
     7 --方法2:设定起止时间,显示时间段内的日期
     8 declare @StartDate DATETIME = '2015/05/01'
     9 declare @EndDate DATETIME ='2015/06/03'
    10 select  dateadd(day,number,@StartDate) as every_time
    11 from master.dbo.spt_values  
    12 where type ='P'
    13 and number <=DATEDIFF(day, @StartDate,   @EndDate)
    14 
    15 --方法3:设定开始时间到当天的所有时间
    16 SELECT DateAdd(day,number,'2018-01-01') as time
    17 FROM master..spt_values  
    18 WHERE type = 'p'  
    19 AND number <= DateDiff(day,'2018-01-01',GetDate()+1)  
    View Code

    7.创建视图

     1 if exists (select * from sysobjects where name = 'View_EdsProd')
     2  drop view View_EdsProd
     3  go
     4  --创建视图
     5 create view View_EdsProd 
     6 as
     7    select * from Tab_EdsProd where Mid>1
     8 go
     9 --使用视图--
    10 select *from View_EdsProd
    View Code

    8.行转列

    将:1   -->    1     转换为1  -->  1,2

           1   -->    2

     Oracle实现:

    1 select id,wm_concat(name) names from table1 group by id
    View Code

    Sql Server实现:

    1  select id, [names]=stuff((select ','+[name] from table1 A t where A.id=B.id for xml path('')), 1, 1, '')
    2    from table1 B
    3  group by id
    View Code
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  • 原文地址:https://www.cnblogs.com/imstrive/p/7285775.html
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