Which join needs to be implement? RRS feed

  • Question

  • User1052662409 posted

    Hi All,

    Last week I was interviewed. The interviewer asked me a question regarding SQL.

    The question is below, you can easily understand by the image. here I have to tables, I need to find records which is uncommon in second table i.e. I need to find out the records which are colored by black color. See the image below.


    Thursday, July 28, 2016 5:31 AM


  • User1724605321 posted

    Hi Gaurav Kumar,

    You could use left join , suppose table 1 has id ,name , table B has id , name , you want to find all records from table2 also not exist in table 1 ,query below is for your reference :

    SELECT t2.name
    FROM table2 t2
    LEFT JOIN table1 t1 ON t1.name = t2.name
    WHERE t1.name IS NULL


    SELECT name
    FROM table2
    WHERE name NOT IN
        (SELECT name 
         FROM table1)

    You could refer to below article for detail explaination :


    Best Regards,

    Nan Yu

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Thursday, July 28, 2016 5:40 AM