How to join complex sql queries within a table using subqueries











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I have a table with "userid", "bookid", "sessionid".



When a book(bookid) is viewed by a visitor(userid), the web application will find all books(bookids) viewed by users(userids) who viewed this book(bookid) and display the top 5 books.










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  • 3




    Great. Do you have a question?
    – Gordon Linoff
    Nov 10 at 13:28












  • Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
    – Jay
    Nov 10 at 13:29










  • @GordonLinoff my question is what will be the sql query to retrieve the top 5 books
    – Achala Yasas Piyarathna
    Nov 10 at 14:27















up vote
0
down vote

favorite
1












I have a table with "userid", "bookid", "sessionid".



When a book(bookid) is viewed by a visitor(userid), the web application will find all books(bookids) viewed by users(userids) who viewed this book(bookid) and display the top 5 books.










share|improve this question


















  • 3




    Great. Do you have a question?
    – Gordon Linoff
    Nov 10 at 13:28












  • Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
    – Jay
    Nov 10 at 13:29










  • @GordonLinoff my question is what will be the sql query to retrieve the top 5 books
    – Achala Yasas Piyarathna
    Nov 10 at 14:27













up vote
0
down vote

favorite
1









up vote
0
down vote

favorite
1






1





I have a table with "userid", "bookid", "sessionid".



When a book(bookid) is viewed by a visitor(userid), the web application will find all books(bookids) viewed by users(userids) who viewed this book(bookid) and display the top 5 books.










share|improve this question













I have a table with "userid", "bookid", "sessionid".



When a book(bookid) is viewed by a visitor(userid), the web application will find all books(bookids) viewed by users(userids) who viewed this book(bookid) and display the top 5 books.







sql join






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asked Nov 10 at 13:25









Achala Yasas Piyarathna

160112




160112








  • 3




    Great. Do you have a question?
    – Gordon Linoff
    Nov 10 at 13:28












  • Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
    – Jay
    Nov 10 at 13:29










  • @GordonLinoff my question is what will be the sql query to retrieve the top 5 books
    – Achala Yasas Piyarathna
    Nov 10 at 14:27














  • 3




    Great. Do you have a question?
    – Gordon Linoff
    Nov 10 at 13:28












  • Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
    – Jay
    Nov 10 at 13:29










  • @GordonLinoff my question is what will be the sql query to retrieve the top 5 books
    – Achala Yasas Piyarathna
    Nov 10 at 14:27








3




3




Great. Do you have a question?
– Gordon Linoff
Nov 10 at 13:28






Great. Do you have a question?
– Gordon Linoff
Nov 10 at 13:28














Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
– Jay
Nov 10 at 13:29




Just as you did above, then access the properties with book.bookid, you can also declare multiple properties e.g. book(bookId int, name char(max))
– Jay
Nov 10 at 13:29












@GordonLinoff my question is what will be the sql query to retrieve the top 5 books
– Achala Yasas Piyarathna
Nov 10 at 14:27




@GordonLinoff my question is what will be the sql query to retrieve the top 5 books
– Achala Yasas Piyarathna
Nov 10 at 14:27












1 Answer
1






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1
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I will assume the following:




  • You are using MySQL as DBMS.

  • With "Top 5 books" you mean "the 5 most viewed books considering the views by the users who viewed the current book".


Assuming as an example that the user is visiting the book 151 at the moment, you can do it with the following query:



SELECT bookid, COUNT(*) AS BookViews
FROM YourTable
WHERE userid IN (SELECT userid FROM YourTable WHERE bookid = 151)
GROUP BY bookid
ORDER BY 2 DESC
LIMIT 5;





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    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    1
    down vote



    accepted










    I will assume the following:




    • You are using MySQL as DBMS.

    • With "Top 5 books" you mean "the 5 most viewed books considering the views by the users who viewed the current book".


    Assuming as an example that the user is visiting the book 151 at the moment, you can do it with the following query:



    SELECT bookid, COUNT(*) AS BookViews
    FROM YourTable
    WHERE userid IN (SELECT userid FROM YourTable WHERE bookid = 151)
    GROUP BY bookid
    ORDER BY 2 DESC
    LIMIT 5;





    share|improve this answer

























      up vote
      1
      down vote



      accepted










      I will assume the following:




      • You are using MySQL as DBMS.

      • With "Top 5 books" you mean "the 5 most viewed books considering the views by the users who viewed the current book".


      Assuming as an example that the user is visiting the book 151 at the moment, you can do it with the following query:



      SELECT bookid, COUNT(*) AS BookViews
      FROM YourTable
      WHERE userid IN (SELECT userid FROM YourTable WHERE bookid = 151)
      GROUP BY bookid
      ORDER BY 2 DESC
      LIMIT 5;





      share|improve this answer























        up vote
        1
        down vote



        accepted







        up vote
        1
        down vote



        accepted






        I will assume the following:




        • You are using MySQL as DBMS.

        • With "Top 5 books" you mean "the 5 most viewed books considering the views by the users who viewed the current book".


        Assuming as an example that the user is visiting the book 151 at the moment, you can do it with the following query:



        SELECT bookid, COUNT(*) AS BookViews
        FROM YourTable
        WHERE userid IN (SELECT userid FROM YourTable WHERE bookid = 151)
        GROUP BY bookid
        ORDER BY 2 DESC
        LIMIT 5;





        share|improve this answer












        I will assume the following:




        • You are using MySQL as DBMS.

        • With "Top 5 books" you mean "the 5 most viewed books considering the views by the users who viewed the current book".


        Assuming as an example that the user is visiting the book 151 at the moment, you can do it with the following query:



        SELECT bookid, COUNT(*) AS BookViews
        FROM YourTable
        WHERE userid IN (SELECT userid FROM YourTable WHERE bookid = 151)
        GROUP BY bookid
        ORDER BY 2 DESC
        LIMIT 5;






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 10 at 15:14









        Antonio Alvarez

        10214




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