【額 原來ms sqlserver 中的視圖果然是“虛表”哈】

標籤：

在視圖中查詢資料的時候，會不會使用實體表中的列上的索引呢？會 。。。。

測試結果

測試指令碼

DECLARE @len INT =100;WHILE @len>0BEGIN        INSERT INTO Teachers            ( TeacherName, Sex, MoneyPay )    VALUES  (                CAST(@len AS NVARCHAR), -- TeacherName - nvarchar(50)              NULL, -- Sex - bit              10000  -- MoneyPay - decimal              )        SET @len-=1;ENDgoDECLARE @len INT =1000;WHILE @len>0BEGIN        INSERT INTO Students            ( StuName, Address, Birthday )    VALUES  ( CAST(@len AS NVARCHAR )+‘-‘+CAST(@len AS NVARCHAR ), -- StuName - nvarchar(50)              N‘‘, -- Address - nvarchar(200)              GETDATE()  -- Birthday - datetime              )              SET @len-=1;ENDgoDECLARE @len_t INT =1;DECLARE @len_stu INT =1;WHILE @len_t<=100BEGIN    SET @len_stu=@len_t;        WHILE @len_stu>0     BEGIN        INSERT INTO TeachAndStudent                ( TeacherId, StudentId, CreateTime )        VALUES  ( @len_t, -- TeacherId - int                  @len_stu, -- StudentId - int                   GETDATE() -- CreateTime - datetime                  )         SET @len_stu-=1;     END        SET @len_t+=1;END------------test:----------------SELECT * FROM Teachers--GO--SELECT * FROM Students--GO--SELECT COUNT(*) FROM TeachAndStudentGO--CREATE VIEW VTeacherAndStudents--AS --SELECT --a.id AS tid,--c.Id AS stuid,--a.TeacherName AS tname,--c.StuName AS sname-- FROM Teachers A--INNER JOIN TeachAndStudent B ON B.TeacherId=A.Id--LEFT JOIN Students C ON C.Id = B.StudentIdGOSELECT * FROM VTeacherAndStudents aWHERE a.tid>10 AND a.tid<20

 

【額 原來ms sqlserver 中的視圖果然是“虛表”哈】