Pure-SQL Technique for Auto-Numbering Rows in Result Set

前端 未结 9 1142
误落风尘
误落风尘 2020-12-29 00:20

I\'m looking for a way to sequentially number rows in a result set (not a table). In essence, I\'m starting with a query like the following:

SELECT         


        
9条回答
  •  青春惊慌失措
    2020-12-29 00:48

    To have a meaningful row number you need to order your results. Then you can do something like this:

    SELECT id, name
        , (SELECT COUNT(*) FROM people p2 WHERE name='Spiewak' AND p2.id <= p1.id) AS RowNumber
    FROM people p1
    WHERE name = 'Spiewak'
    ORDER BY id
    

    Note that the WHERE clause of the sub query needs to match the WHERE clause or the primary key from the main query and the ORDER BY of the main query.

    SQL Server has the ROW_NUMBER() OVER construct to simplify this, but I don't know if MySQL has anything special to address it.


    Since my post here was accepted as the answer, I want to also call out Dan Goldstein's response, which is very similar in approach but uses a JOIN instead of a sub query and will often perform better

提交回复
热议问题