LEFT JOIN vs. LEFT OUTER JOIN in SQL Server

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失恋的感觉
失恋的感觉 2020-11-21 13:25

What is the difference between LEFT JOIN and LEFT OUTER JOIN?

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  •  暗喜
    暗喜 (楼主)
    2020-11-21 13:55

    I'm a PostgreSQL DBA, as far as I could understand the difference between outer or not outer joins difference is a topic that has considerable discussion all around the internet. Until today I never saw a difference between those two; So I went further and I try to find the difference between those. At the end I read the whole documentation about it and I found the answer for this,

    So if you look on documentation (at least in PostgreSQL) you can find this phrase:

    "The words INNER and OUTER are optional in all forms. INNER is the default; LEFT, RIGHT, and FULL imply an outer join."

    In another words,

    LEFT JOIN and LEFT OUTER JOIN ARE THE SAME

    RIGHT JOIN and RIGHT OUTER JOIN ARE THE SAME

    I hope it can be a contribute for those who are still trying to find the answer.

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