SQL Server Transact-SQL進階查詢

進階查詢在資料庫中用得是最頻繁的，也是應用最廣泛的。

Ø  基本常用查詢

--selectselect * from student;--all 查詢所有select all sex from student;--distinct 過濾重複select distinct sex from student;--count 統計select count(*) from student;select count(sex) from student;select count(distinct sex) from student;--top 取前N條記錄select top 3 * from student;--alias column name 列重新命名select id as 編號, name '名稱', sex 性別 from student;--alias table name 表重新命名select id, name, s.id, s.name from student s;--column 列運算select (age + id) col from student;select s.name + '-' + c.name from classes c, student s where s.cid = c.id;--where 條件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 並且select * from student where id > 2 and sex = 1;--or 或者select * from student where id = 2 or sex = 1;--between ... and ... 相當於並且select * from student where id between 2 and 5;select * from student where id not between 2 and 5;--like 模糊查詢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 子查詢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 不為空白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 分組按照年齡進行分組統計select count(age), age from student group by age;按照性別進行分組統計select count(*), sex from student group by sex;按照年齡和性別組合分組統計，並排序select count(*), sex from student group by sex, age order by age;按照性別分組，並且是id大於2的記錄最後按照性別排序select count(*), sex from student where id > 2 group by sex order by sex;查詢id大於2的資料，並完成運算後的結果進行分組和排序select count(*), (sex * id) new from student where id > 2 group by sex * id order by sex * id;--group by all 所有分組按照年齡分組，是所有的年齡select count(*), age from student group by all age;--having 分組過濾條件按照年齡分組，過濾年齡為空白的資料，並且統計分組的條數和現實年齡資訊select count(*), age from student group by age having age is not null;按照年齡和cid組合分組，過濾條件是cid大於1的記錄select count(*), cid, sex from student group by cid, sex having cid > 1;按照年齡分組，過濾條件是分組後的記錄條數大於等於2select count(*), age from student group by age having count(age) >= 2;按照cid和性別組合分組，過濾條件是cid大於1，cid的最大值大於2select count(*), cid, sex from student group by cid, sex having cid > 1 and max(cid) > 2;

 Ø  嵌套子查詢

       子查詢是一個嵌套在select、insert、update或delete語句或其他子查詢中的查詢。任何允許使用運算式的地方都可以使用子查詢。子查詢也稱為內部查詢或內部選擇，而包含子查詢的語句也成為外部查詢或外部選擇。

       # from (select … table)樣本

將一個table的查詢結果當做一個新表進行查詢select * from (select id, name from student where sex = 1) t where t.id > 2;

上面括弧中的語句，就是子查詢語句（內部查詢）。在外面的是外部查詢，其中外部查詢可以包含以下語句：

       1、 包含常規挑選清單組件的常規select查詢

       2、 包含一個或多個表或視圖名稱的常規from語句

       3、 可選的where子句

       4、 可選的group by子句

       5、 可選的having子句

       #  樣本

查詢班級資訊，統計班級學生人生select *, (select count(*) from student where cid = classes.id) as num from classes order by num;

       #  in, not in子句查詢樣本

查詢班級id大於小於的這些班級的學生資訊select * from student where cid in (select id from classes where id > 2 and id < 4);查詢不是班的學生資訊select * from student where cid not in (select id from classes where name = '2班')

            in、not in 後面的子句返回的結果必須是一列，這一列的結果將會作為查詢條件對應前面的條件。如cid對應子句的id；

       # exists和not exists子句查詢樣本

查詢存在班級id為的學生資訊select * from student where exists (select * from classes where id = student.cid and id = 3);查詢沒有分配班級的學生資訊select * from student where not exists (select * from classes where id = student.cid);

       exists和not exists查詢需要內部查詢和外部查詢進行一個關聯的條件，如果沒有這個條件將是查詢到的所有資訊。如：id等於student.id；

       #  some、any、all子句查詢樣本

查詢班級的學生年齡大於班級的學生的年齡的資訊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  彙總查詢

       1、 distinct去掉重複資料

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

       2、 compute和compute by匯總查詢

對年齡大於的進行匯總select age from student where age > 20 order by age compute sum(age) by age;對年齡大於的按照性別進行分組匯總年齡資訊select id, sex, age from student where age > 20 order by sex, age compute sum(age) by sex;按照年齡分組匯總select age from student where age > 20 order by age, id compute sum(age);按照年齡分組，年齡匯總，id找最大值select id, age from student where age > 20 order by age compute sum(age), max(id);

       compute進行匯總前面是查詢的結果，後面一條結果集就是匯總的資訊。compute子句中可以添加多個匯總運算式，可以添加的資訊如下：

              a、 可選by關鍵字。它是每一列計算指定的行彙總

              b、 資料列彙總函式名稱。包括sum、avg、min、max、count等

              c、 要對其執資料列彙總函式的列

              compute by適合做先分組後匯總的業務。compute by後面的列一定要是order by中出現的列。

       3、 cube匯總

              cube匯總和compute效果類似，但文法較簡潔，而且返回的是一個結果集。

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要結合group by陳述式完成分組匯總

Ø  排序函數

      排序在很多地方需要用到，需要對查詢結果進行排序並且給出序號。比如：

      1、  對某張表進行排序，序號需要遞增不重複的

      2、  對學生的成績進行排序，得出名次，名次可以並列，但名次的序號是連續遞增的

      3、  在某些排序的情況下，需要跳空序號，雖然是並列

      基本文法

排序函數 over([分組語句] 排序子句[desc][asc])排序子句 order by 列名, 列名分組子句 partition by 分組列, 分組列

      #  row_number函數

            根據排序子句給出遞增連續序號

按照名稱排序的順序遞增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函數函數

            根據排序子句給出遞增的序號，但是存在並列並且跳空

順序遞增select id, name, rank() over(order by cid) as rank from student;跳過相同遞增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函數

            根據排序子句給出遞增的序號，但是存在並列不跳空

不跳過，直接遞增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分組子句

            可以完成對分組的資料進行增加排序，partition by可以與以上三個函數聯合使用。

利用partition by按照班級名稱分組，學生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平均排序函數

            將要排序的資料進行平分，然後按照等分排序。ntile中的參數代表分成多少等分。

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  集合運算

      操作兩組查詢結果，進行交集、並集、減集運算

      1、 union和union all進行並集運算

--union 並集、不重複select id, name from student where name like 'ja%'unionselect id, name from student where id = 4;--並集、重複select * from student where name like 'ja%'union allselect * from student;

      2、 intersect進行交集運算

--交集（相同部分）select * from student where name like 'ja%'intersectselect * from student;

      3、 except進行減集運算

--減集（除相同部分）select * from student where name like 'ja%'exceptselect * from student where name like 'jas%';

Ø  公式表運算式

       查詢表的時候，有時候中間表需要重複使用，這些子查詢被重複查詢調用，不但效率低，而且可讀性低，不利於理解。那麼公式表運算式可以解決這個問題。

      我們可以將公式表運算式（CET）視為臨時結果集，在select、insert、update、delete或是create view語句的執行範圍內進行定義。

--運算式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  串連查詢

     1、 簡化串連查詢

--簡化聯結查詢select s.id, s.name, c.id, c.name from student s, classes cwhere s.cid = c.id;

      2、 left join左串連

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

      3、 right join右串連

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

      4、 inner join內串連

--內串連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;

      5、 cross join交叉串連

--交叉聯結查詢，結果是一個笛卡兒乘積select s.id, s.name, c.id, c.name from student s cross join classes c--where s.cid = c.id;

      6、 自串連（同一張表進行串連查詢）

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

Ø  函數

      1、  彙總函式

            max最大值、min最小值、count統計、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、  日期時間函數

select dateAdd(day, 3, getDate());--加天select dateAdd(year, 3, getDate());--加年select dateAdd(hour, 3, getDate());--加小時--返回跨兩個指定日期的日期邊界數和時間邊界數select dateDiff(day, '2011-06-20', getDate());--相差秒數select dateDiff(second, '2011-06-22 11:00:00', getDate());--相差小時數select dateDiff(hour, '2011-06-22 10:00:00', getDate());select dateName(month, getDate());--當前月份select dateName(minute, getDate());--當前分鐘select dateName(weekday, getDate());--當前星期select datePart(month, getDate());--當前月份select datePart(weekday, getDate());--當前星期select datePart(second, getDate());--當前秒數select day(getDate());--返回當前日期天數select day('2011-06-30');--返回當前日期天數select month(getDate());--返回當前日期月份select month('2011-11-10');select year(getDate());--返回當前日期年份select year('2010-11-10');select getDate();--當前系統日期select getUTCDate();--utc日期

      3、  數學函數

select pi();--PI函數select rand(100), rand(50), rand(), rand();--隨機數select round(rand(), 3), round(rand(100), 5);--精確小數位--精確位元，負數表示小數點前select round(123.456, 2), round(254.124, -2);select round(123.4567, 1, 2);

      4、  中繼資料

select col_name(object_id('student'), 1);--返回列名select col_name(object_id('student'), 2);--該列資料類型長度select col_length('student', col_name(object_id('student'), 2)); --該列資料類型長度select col_length('student', col_name(object_id('student'), 1)); --傳回型別名稱、類型idselect type_name(type_id('varchar')), type_id('varchar');--返回列類型長度select columnProperty(object_id('student'), 'name', 'PRECISION');--返回列所在索引位置select columnProperty(object_id('student'), 'sex', 'ColumnId');

      5、  字串函數

select ascii('a');--字元轉換ascii值select ascii('A');select char(97);--ascii值轉換字元select char(65);select nchar(65);select nchar(45231);select nchar(32993);--unicode轉換字元select unicode('A'), unicode('中');--返回unicode編碼值select soundex('hello'), soundex('world'), soundex('word');select patindex('%a', 'ta'), patindex('%ac%', 'jack'), patindex('dex%', 'dexjack');--匹配字元索引select 'a' + space(2) + 'b', 'c' + space(5) + 'd';--輸出空格select charIndex('o', 'hello world');--尋找索引select charIndex('o', 'hello world', 6);--尋找索引select quoteName('abc[]def'), quoteName('123]45');--精確數字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');--比較字串相同select difference('hello', 'world');select difference('hello', 'llo');select difference('hello', 'hel');select difference('hello', 'hello');select replace('abcedef', 'e', 'E');--替換字串select stuff('hello world', 3, 4, 'ABC');--指定位置替換字串select replicate('abc#', 3);--重複字串select subString('abc', 1, 1), subString('abc', 1, 2), subString('hello Wrold', 7, 5);--截取字串select len('abc');--返回長度select reverse('sqlServer');--反轉字串select left('leftString', 4);--取左邊字串select left('leftString', 7);select right('leftString', 6);--取右邊字串select right('leftString', 3);select lower('aBc'), lower('ABC');--小寫select upper('aBc'), upper('abc');--大寫--去掉左邊空格select ltrim(' abc'), ltrim('# abc#'), ltrim('  abc');--去掉右邊空格select rtrim(' abc    '), rtrim('# abc#   '), rtrim('abc');

      6、  安全函數

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、  系統函數

select app_name();--當前會話的應用程式名稱select cast(2011 as datetime), cast('10' as money), cast('0' as varbinary);--類型轉換select convert(datetime, '2011');--類型轉換select coalesce(null, 'a'), coalesce('123', 'a');--返回其參數中第一個非空運算式select collationProperty('Traditional_Spanish_CS_AS_KS_WS', 'CodePage');select current_timestamp;--目前時間戳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');--返回主鍵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;--最後一次自增的值select identity(int, 1, 1) as id into tab from student;--將studeng表的烈屬，以/1自增形式建立一個tabselect * from tab;select @@rowcount;--影響行數select @@cursor_rows;--返回串連上開啟的遊標的當前限定行的數目select @@error;--T-SQL的錯誤號碼select @@procid;

      8、  配置函數

set datefirst 7;--設定每周的第一天，表示周日select @@datefirst as '星期的第一天', datepart(dw, getDate()) AS '今天是星期';select @@dbts;--返回當前資料庫唯一時間戳記set language 'Italian';select @@langId as 'Language ID';--返回語言idselect @@language as 'Language Name';--返回當前語言名稱select @@lock_timeout;--返回當前會話的當前鎖定逾時設定（毫秒）select @@max_connections;--返回SQL Server 執行個體允許同時進行的最大使用者串連數select @@MAX_PRECISION AS 'Max Precision';--返回decimal 和numeric 資料類型所用的精度層級select @@SERVERNAME;--SQL Server 的本機伺服器的名稱select @@SERVICENAME;--服務名select @@SPID;--當前會話進程idselect @@textSize;select @@version;--當前資料庫版本資訊

      9、  系統統計函數

select @@CONNECTIONS;--串連數select @@PACK_RECEIVED;select @@CPU_BUSY;select @@PACK_SENT;select @@TIMETICKS;select @@IDLE;select @@TOTAL_ERRORS;select @@IO_BUSY;select @@TOTAL_READ;--讀取磁碟次數select @@PACKET_ERRORS;--發生的網路資料包錯誤數select @@TOTAL_WRITE;--sqlserver執行的磁碟寫入次數select patIndex('%soft%', 'microsoft SqlServer');select patIndex('soft%', 'software SqlServer');select patIndex('%soft', 'SqlServer microsoft');select patIndex('%so_gr%', 'Jsonisprogram');

      10、  使用者自訂函數

            # 查看當前資料庫所有函數

--查詢所有已建立函數select definition,* from sys.sql_modules m join sys.objects o on m.object_id = o.object_idand type in('fn', 'if', 'tf'); 

            #  建立函數

if (object_id('fun_add', 'fn') is not null)drop function fun_addgocreate function fun_add(@num1 int, @num2 int)returns intwith execute as callerasbegindeclare @result int;if (@num1 is null)set @num1 = 0;if (@num2 is null)set @num2 = 0;set @result = @num1 + @num2;return @result;endgo調用函數select dbo.fun_add(id, age) from student;--自訂函數，字串串連if (object_id('fun_append', 'fn') is not null)drop function fun_appendgocreate function fun_append(@args nvarchar(1024), @args2 nvarchar(1024))returns nvarchar(2048)asbeginreturn @args + @args2;endgoselect dbo.fun_append(name, 'abc') from student;

            #  修改函數

alter function fun_append(@args nvarchar(1024), @args2 nvarchar(1024))returns nvarchar(1024)asbegindeclare @result varchar(1024);--coalesce返回第一個不為null的值set @args = coalesce(@args, '');set @args2 = coalesce(@args2, '');;set @result = @args + @args2;return @result;endgoselect dbo.fun_append(name, '#abc') from student;

            #  返回table類型函數

--返回table對象函數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_stuRecordgocreate function fun_find_stuRecord(@id int)returns tableasreturn (select * from student where id = @id);goselect * from dbo.fun_find_stuRecord(2);