sql server t-sql高階查詢

新增欄位：
alter table [表名] add [欄位名] nvarchar (50) null
alter table [表名]
      alter column [欄位名]     varchar(100)  not null

--刪除欄位：
alter table [表名] drop column [欄位名]

--修改欄位：
alter table [表名] alter column [欄位名] nvarchar (50) null

--重命名錶：(access 重命名錶，請參考文章：在access資料庫中重命名錶)
sp_rename '表名', '新表名', 'object'

--新建約束：
alter table [表名] add constraint 約束名 check ([約束欄位] <= '2000-1-1')

--刪除約束：
alter table [表名] drop constraint 約束名

--新建預設值
alter table [表名] add constraint 預設值名 default '51windows.net' for [欄位名]

--刪除預設值
alter table [表名] drop constraint 預設值名


高階查詢在資料庫中用得是最頻繁的，也是應用最廣泛的。

? 基本常用查詢

--select
select * 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]%';  --中間字元含a,o的
select * from student where name not like  '%a%';  
select * from student where name like 'ja%';        --開頭含ja的
select * from student where name not like '%[j,n]%';
select * from student where name like '%[j,n,a]%';  --中間字元含j,n,a中任意一
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
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2
select 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2
select count(*), cid, sex from student group by cid, sex having cid > 1 and max(cid) > 2;
? 巢狀子查詢

    子查詢是一個巢狀在select、insert、update或delete語句或其他子查詢中的查詢。
	任何允許使用表示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)示例

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;
上面括號中的語句，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、 包含常規選擇列表元件的常規select查詢

     2、 包含一個或多個表或檢視名稱的常規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

 

# 示例

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子句查詢示例

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子句查詢示例

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子句查詢示例

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
);
 

? 聚合查詢

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彙總查詢

對年齡大於的進行彙總
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彙總年齡資訊
select id, sex, age from student 
where age > 20 order by sex, age compute sum(age) by sex;
 
按照年齡分組彙總
select age from student 
where age > 20 order by age, id compute sum(age);
 
按照年齡分組，年齡彙總，id找最大值
select id, age from student 
where age > 20 order by age compute sum(age), max(id);
compute進行彙總前面是查詢的結果，後面一條結果集就是彙總的資訊。
compute子句中可以新增多個彙總表示式，可以新增的資訊如下：

     a、 可選by關鍵字。它是每一列計算指定的行聚合

     b、 行聚合函式名稱。包括sum、avg、min、max、count等

     c、 要對其執行聚合函式的列

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

 

3、 cube彙總

cube彙總和compute效果類似，但語法較簡潔，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語句完成分組彙總


4.動態查詢
 where panelid<>-1  
    and ((@itemid=-1) or (
 
[email protected]))  
    and ((@prodorderid=-1) or ([email protected]))  
    and ((@lineid=-1) or (resid in(select resid from #tmpres)))  
    and ((@opid=-1) or ([email protected]))
 

? 排序函式

   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

基本語法

排序函式 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函式

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函式函式

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函式

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可以與以上三個函式聯合使用。

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平均排序函式

將要排序的資料進行平分，然後按照等分排序。ntile中的引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;
 

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

2、 intersect進行交集運算

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

3、 except進行減集運算

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

? 公式表表達式

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呼叫，不但效率低，
而且可讀性低，不利於理解。那麼公式表表達式可以解決這個問題。

我們可以將公式表表達式（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。

--表示式
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;
 

? 連線查詢

1、 簡化連線查詢

--簡化聯接查詢
select s.id, s.name, c.id, c.name from student s, classes c where s.cid = c.id;
 

2、 left join左連線

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

3、 right join右連線

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

4、 inner join內連線

--內連線
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交叉連線

--交叉聯接查詢，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、 自連線（同一張表進行連線查詢）

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

? 函式

1、 聚合函式

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、 日期時間函式

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、 數學函式

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

4、 元資料

select col_name(object_id('student'), 1);--返回列名
select col_name(object_id('student'), 2);
--該列資料型別長度
select col_length('student', col_name(object_id('student'), 2)); 
--該列資料型別長度
select col_length('student', col_name(object_id('student'), 1)); 
--返回型別名稱、型別id
select type_name(type_id('varchar')), type_id('varchar');
--返回列型別長度
select columnproperty(object_id('student'), 'name', 'precision');
--返回列所在索引位置
select columnproperty(object_id('student'), 'sex', 'columnid');
 

5、 字串函式

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');--查詢索引
select charindex('o', 'hello world', 6);--查詢索引
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);--擷取字串
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、 安全函式

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、 系統函式

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);--型別轉換
select convert(datetime, '2011');--型別轉換
select coalesce(null, 'a'), coalesce('123', 'a');--返回其引數中第一個非空表示式
select collationproperty('traditional_spanish_cs_as_ks_ws', 'codepage');
select current_timestamp;--當前時間戳
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tab
select * from tab;
select @@rowcount;--影響行數
select @@cursor_rows;--返回連線上開啟的遊標的當前限定行的數目
select @@error;--t-sql的錯誤號
select @@procid;
 

8、 配置函式

set datefirst 7;--設定每週的第一天，表示週日
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
set language 'italian';
select @@langid as 'language id';--返回語言id
select @@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超時設定（毫秒）
select @@max_connections;--返回sql server 例項允許同時進行的最大使用者連線數
select @@max_precision as 'max precision';--返回decimal 和numeric 資料型別所用的精度級別
select @@servername;--sql server 的本地伺服器的名稱
select @@servicename;--服務名
select @@spid;--當前會話程序id
select @@textsize;
select @@version;--當前資料庫版本資訊
 

9、 系統統計函式

select @@connections;--連線數
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、 使用者自定義函式

# 檢視當前資料庫所有函式

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

# 建立函式

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
呼叫函式
select dbo.fun_add(id, age) from student;
 
--自定義函式，字串連線
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;
 

# 修改函式

alter function fun_append(@args nvarchar(1024), @args2 nvarchar(1024))
    returns nvarchar(1024)
as
    begin
        declare @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;
    end
go
 
select dbo.fun_append(name, '#abc') from student;
 

# 返回table型別函式

--返回table物件函式
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);


#執行帶返回值的過程。
declare @p4 int
set @p4=-1
declare @p5 varchar(255)
set @p5=''''''
exec proc '',1,'',@p4 output,@p5 output
select @p4, @p5


# 查詢帶%的
case when perdd_standard <> 0 
       then ltrim(str(perdd_actual/perdd_standard*100,10,2)) + '%' 
       else '0.0%' end  as perdd_efff from perdd_det

# 開啟遠端伺服器
 select a.*  opendatasource('SQLOLEDB','Data Source=192.168.1.XX;User ID=user;Password=pwd').DB_Name.dbo.table_name  


# 檢視系統有沒有死鎖
use master
select * from sysprocesses where blocked<>0
--找到spid  
exec sp_lock
--根據spid找到objid
select object_name(85575343)
--根據objid找到表名


多表join做update 
update t1 set col1=t2.col1
from table1 t1
inner join table2 t2 on t1.col2=t2.col2

sqlite中可轉換為 如下語法 
update table1 set col1=(select col1 from table2 where col2=table1.col2)


# with (nolock) 用法
1：使用with(nolock)時查詢不受其它排他鎖阻塞
begin tran 
   update  si_mstr set si_company = '1000'  where si_site = '1000'
--rollback tran 

另開查詢視窗,會發現查不出來
   select * from  si_mstr
此時要用with (nolock) ，能查，但會出現髒讀，如果事務回滾會出現查詢和實際資料不一致
   select * from  si_mstr  with (nolock) 

2.寫法
    select * from test nolock         --表別名的寫法
    select * from test (nolock);      --sql 2008以下寫法
    select * from test with(nolock);  --完全寫法


#儲存過程引數賦預設值
create procedure dbo.my_proc
    @first  int = null,  -- null default value
    @second int = 2,     -- default value of 2
    @third  int = 3      -- default value of 3
as 
    set nocount on;
    select @first, @second, @third;
go


#分頁查詢
--分頁1 select top 3 * from student where [sId] not in (select top (3*(4-1)) [sid] from student)--4表示頁數 select *, row_number() over(order by [sage] desc ) from student-- row_number() over (order by..)獲取行號 

--分頁2 select * from (select *, row_number() over(order by [sid] desc ) as num from student)as t where num between (Y-1)*T+1 and Y*T order by [sid] desc 

--分頁3 select * from (select ROW_NUMBER() over( order by [UnitPrice] asc) as num,* from [Books] where [publisherid]=1 )as t where t.num between 1 and 20 --要查詢的開始條數和結束條數