使用SQL Server 2008 R2中的临时表优化表的性能

Question

Good day, I'm quite a newbie in optimizing database queries...actually it's my very first time... I've done my research and found out that using temporary tables could help me improve the queries performance.. Aside from other solutions like using index but though their are a lot of blogs about it I haven't yet to find a well detailed tutorial about it... I was hoping if you could kindly help. Given this sample table...

Table Schemas::

    StudentInfo:
    StudentID 
    LAstname
    FirstName
    YearCode
    SectionCode

    TeacherInfo:
    SectionCode
    TeacherID
    TeacherName


    GradeInfo:
    StudentID
    AverageGrade

    CashierRecord:
    StudentID
    EnrolledDate
    ModeOfPayment
    AmountDue

Query I have Tried...

 Select 
        s.StudentID,
        s.FirstName,
        s.LastName,
        t.Teacher,
        g.AverageGrade,
        c.EnrolledDate
    From StudentInfo s
    LEFT JOIN TeacherInfo t ON s.StudentID= t.StudentID
    LEFT JOIN GradeInfo g ON s.StudentID= g.StudentID
    LEFT JOIN GradeRecords c ON s.StudentID= c.StudentID

If the given query would retrieve a huge amount of data (ex. 100,000 records) the query would surely run low in performance... may you kindly explain how could I utilize TEMPORARY TABLES to store the data from multiple tables so that retrieval could be easier...

Answer 1

To create a table from a select result in SQL server you could use select into .

Select 
    s.StudentID,
    s.FirstName,
    s.LastName,
    t.Teacher,
    g.AverageGrade,
    c.EnrolledDate
into TEMPTABLE
From StudentInfo s
LEFT JOIN TeacherInfo t ON s.StudentID= t.StudentID
LEFT JOIN GradeInfo g ON s.StudentID= g.StudentID
LEFT JOIN GradeRecords c ON s.StudentID= c.StudentID

Then you could use TEMPTABLE and then drop it using

drop table TEMPTABLE

With this you have collected your data to one table. TEMPTABLE is not yet a real temporary table. Look here to find more on that ( Is it necessary to use # for creating temp tables in SQL server? ). It comes down to write #TEMPTABLE .

But to build this table you still have the processing time of your select.