Results 1 to 3 of 3

Thread: ques

  1. #1
    Junior Member
    Join Date
    Aug 2011


    Pls any one explain the difference between left join & left outer join with example??

  2. #2
    Expert Member
    Join Date
    Mar 2012

    Re: ques

    Left join and left outer join are one and the same.The use of word "outer" is optional.

    A left outer join will select all records from the first table, and any records in the second table that match the joined keys.When a row in the left table has no matching rows in the right table, the associated result set row contains null values for all select list columns coming from the right table.


    SELECT *
    FROM user u
    LEFT OUTER JOIN telephone t ON t.user_id =

    The above example will return a list of all users, plus any telephone records if they are available (if they aren't available, you'll get NULL for the telephone values).

  3. #3
    Junior Member
    Join Date
    May 2012

    Re: ques

    The keyword OUTER is optional, but in my opinion it should be mandatory. Until such time as it is, my advice is always to write it, to remind yourself that it's an outer join.

    The keyword LEFT, RIGHT, or FULL is mandatory. Left, right, and full outer joins are the only types of outer join. And of course the keyword JOIN is mandatory.

    You mentioned INNER JOIN. This is not the same as FULL OUTER JOIN. INNER means all result rows are rows that were produced by match some condition between the two tables. An outer join has result rows where sometimes there isn't a match, yet rows from one table, or the other, or both, are returned without a match.

    There is one other type of join besides inner and outer, and that's the CROSS JOIN, but that's a different question for another day.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
About us
Applying for a job can be a stressful and frustrating experience, especially for someone who has never done it before. Considering that you are competing for the position with a at least a dozen other applicants, it is imperative that you thoroughly prepare for the job interview, in order to stand a good chance of getting hired. That's where GeekInterview can help.