查詢    

/****** Script for SelectTopNRows command from SSMS  ******/
SELECT TOP 1000 [StudentNo]
      ,[LoginPwd]
      ,[StudentName]
      ,[Sex]
      ,[GradeId]
      ,[Phone]
      ,[Address]
      ,[BornDate]
      ,[Email]
  FROM [MySchool].[dbo].[Student]
  
  --查詢所有的資料行和列
  SELECT * FROM dbo.Student
  
  查詢部分行或列
  SELECT StudentNo ,StudentName ,GradeId FROM dbo.Student WHERE Sex='女' AND GradeId=1
 
 --查詢中使用列的別名
 SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級 FROM dbo.Student  WHERE Sex='男' AND GradeId=2
 
  --查詢空值(採用 "IS NULL"或"IS NOT NULL"來判斷是否為空)
  SELECT 姓名=StudentName,性別=Sex,年級=GradeId,Email FROM dbo.Student WHERE  Email IS NULL
 --------------
  SELECT 姓名=StudentName,性別=Sex,年級=GradeId,Email FROM dbo.Student WHERE  Email IS NOT NULL
   
  
  --查詢中使用常量列(將常量的預設值新增到查詢輸出中) 
  SELECT '北大青鳥' AS 學校,StudentNo AS 學號,StudentName AS 姓名,Sex AS 性別,GradeId AS 年級,Phone AS 聯絡方式, Email FROM dbo.Student
 
 -- 查詢返回限制的行數 (查詢部分前十列,使用TOP關鍵字約束)
 SELECT TOP 10 StudentNo,StudentName,Sex,GradeId FROM dbo.Student WHERE GradeId=1
 
 
 --查詢返回限制的行數 (查詢百分比提取記錄,使用PERCENT關鍵字來限制)
 SELECT TOP 20 PERCENT StudentNo AS 學號,StudentName AS 姓名,Sex AS 性別,GradeId AS 年級 FROM dbo.Student WHERE Sex='男'
 
 --(1990年後出生的學生姓名)
 SELECT * FROM dbo.Student WHERE BornDate>1990
 
 
 
 
 
 
 -------(字串函式)
 
 --查詢所在位置
 SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,CHARINDEX('6',Phone,1)as 位置,Address AS 地址   FROM dbo.Student  WHERE Sex='男' AND GradeId=2
 
 
 --查詢長度
SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,Address AS 地址,LEN(Address)AS 長度  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  
  
  --轉換成大寫
  SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,Address AS 地址,Email,UPPER(Email)AS 大寫Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  
  
  --清除字元左邊的空格
                           --新增空格
  SELECT StudentNo AS 學號,' '+StudentName+' ' AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,Address AS 地址,Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  --左邊的空格
  SELECT StudentNo AS 學號,' '+StudentName+' ' AS 姓名,LTRIM(StudentName), GradeId AS 年級,Phone AS 聯絡方式 ,Address AS 地址,Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  --右邊的空格
  SELECT StudentNo AS 學號,' '+StudentName+' ' AS 姓名,RTRIM(StudentName), GradeId AS 年級,Phone AS 聯絡方式 ,Address AS 地址,Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  
  
  --從字串右邊返回指定數目的字元
  SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,RIGHT(Phone,4)AS 右邊四位數, Address AS 地址,Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
   --從字串左邊返回指定數目的字元
  SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 ,left(Phone,4)AS 左邊四位數, Address AS 地址,Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  
  
  --替換一個字串中的字元
   SELECT StudentNo AS 學號,StudentName AS 姓名, GradeId AS 年級,Phone AS 聯絡方式 , Address AS 地址,REPLACE(Address,'學生','優秀')AS 替換後地址, Email  FROM dbo.Student  WHERE Sex='男' AND GradeId=2
  
  
  --刪除指定長度的字元,並在該位置插入新的字串
  SELECT StudentName AS 姓名,Phone AS 聯絡方式,STUFF(Phone,3,5,'***')AS 插入後,Address AS 地址 FROM dbo.Student 
  
  
  
  
  
  
  -------(日期函式)
  --yy,yyyy(年)  mm,m(月)  wk,ww(周)  dw,w(日期) mi,n(分) ss,s(秒) 
  --取得當前系統日期
  SELECT StudentNo,StudentName,Address,BornDate,GETDATE()AS 當前日期,Email FROM dbo.Student 
  
  
  --將指定的數值新增到指定日期(月份)
  SELECT StudentNo,StudentName,Address,BornDate,DATEADD(MM,4,BornDate )AS 新增後日期,Email FROM dbo.Student 
  
  
  --指定日期部分的間隔(月份)
  SELECT StudentNo,StudentName,Address,BornDate,DATEDIFF(MM,'1995-9-9',BornDate)AS 日期間隔,Email FROM dbo.Student 
   
   
   --指定日期部分字串形式(weekday)
   SELECT StudentNo,StudentName,Address,BornDate,DATENAME(DW,BornDate)AS 字串形式,Email FROM dbo.Student 
   
   
   --指定日期部分的整數形式
   --(整數--年)
   SELECT StudentNo,StudentName,Address,BornDate,DATEPART(year,BornDate)AS 整數型式,Email FROM dbo.Student 
   --(整數--月)
   SELECT StudentNo,StudentName,Address,BornDate,DATEPART(month,BornDate)AS 整數型式,Email FROM dbo.Student 
   --(整數--日)
   SELECT StudentNo,StudentName,Address,BornDate,DATEPART(DAY,BornDate)AS 整數型式,Email FROM dbo.Student 
   
   
  
  
  
  --------數學函式
  
  --返回從0到1之間的隨機float值
  SELECT RAND() 
  
  --取數值表示式的絕對值
  SELECT ABS(-78),ABS(-63)
  
         --取整數        冪值           指定精度                    平方根     
  SELECT CEILING(55.6), POWER(5,2), ROUND(45.321,1),ROUND(23.212,2),SQRT(9)
  
  --正數返回+1,負數返回-1,0則返回0
  SELECT SIGN(-45),SIGN(23) 
  
  
  
  
  
  
  ------系統函式
  
      --轉變資料型別               返回當前使用者姓名      位元組數            計算機名字   所登入使用者名稱  使用者ID返回使用者名稱
  SELECT CONVERT(VARCHAR(5),12345), CURRENT_USER ,  DATALENGTH('滴滴答答'),HOST_NAME(), SYSTEM_USER,  USER_NAME(1)
  
  
  
  
  
  
  
  
 -- (E-maill中@的位置) 
 SELECT Email,CHARINDEX('@',Email,1 ) FROM dbo.Student 
 
 --(E-maill的長度)
  SELECT Email,LEN(Email) FROM dbo.Student
  
 
 

   排序

/****** Script for SelectTopNRows command from SSMS  ******/
SELECT TOP 1000 [Id]
      ,[StudentNo]
      ,[SubjectId]
      ,[StudentResult]
      ,[ExamDate]
  FROM [MySchool].[dbo].[Result]
  --檢視第一學期所有學生資訊
  SELECT  * FROM [MySchool].[dbo].[Result] WHERE SubjectId=1
  
  
  --檢視第二學期所有學生的資訊
  SELECT * FROM [MySchool].[dbo].[Result] WHERE SubjectId=2
  
  
  --檢視第三學期所有學生的資訊
  SELECT * FROM dbo.Result WHERE SubjectId=3
 
 
 --檢視StudentResult超過60的資訊
 SELECT * FROM dbo.Result WHERE StudentResult>60
 
 --查詢排序(使用ORDER BY進行排序   ASC:"升序--[預設]"  DESC:"降序")
 --ExamDate(升序輸出)
 SELECT * FROM dbo.Result  ORDER BY  ExamDate 
 
 
 --StudentResult(降序輸出)
 SELECT * FROM dbo.Result ORDER BY StudentResult DESC
  
  --按日期,成績,編號為1的考試科目資訊
  SELECT ExamDate,StudentResult,SubjectId  FROM dbo.Result WHERE SubjectId=1  ORDER BY ExamDate , StudentResult DESC   
 
  --前五名學生成績
  SELECT TOP 5 StudentResult FROM dbo.Result  WHERE ExamDate='2013-3-22'
  
  --查詢學號"S1101003"考試資訊,先後順序顯示
  SELECT StudentNo,StudentResult,ExamDate FROM dbo.Result WHERE StudentNo='s1101003'  ORDER BY ExamDate