SQL JOIN - WHERE clause vs. ON clause

前端 未结 19 1578
深忆病人
深忆病人 2020-11-21 11:56

After reading it, this is not a duplicate of Explicit vs Implicit SQL Joins. The answer may be related (or even the same) but the question is diffe

19条回答
  •  爱一瞬间的悲伤
    2020-11-21 12:31

    On an inner join, they mean the same thing. However you will get different results in an outer join depending on if you put the join condition in the WHERE vs the ON clause. Take a look at this related question and this answer (by me).

    I think it makes the most sense to be in the habit of always putting the join condition in the ON clause (unless it is an outer join and you actually do want it in the where clause) as it makes it clearer to anyone reading your query what conditions the tables are being joined on, and also it helps prevent the WHERE clause from being dozens of lines long.

提交回复
热议问题