Question

我有一张包含以下结构的表格：

javac

现在我想找到所有用户购买的第三个（基于已购买的数量）不同商品（操作）。那么请你帮我查询一下。抱歉，表格格式不正确。

Answer 1

我认为你的描述中有类似的东西听起来是正确的。首先按计数选择前3个，按项目分组并按计数降序排序。然后选择该组中的前1个按计数升序排序。请记住，我并不是100％熟悉HiveSQL，但是这个SQL代码应该非常接近标准：

SELECT TOP 1 itemName
FROM (
      SELECT TOP 3 itemName, COUNT(*) AS boughtCount
      FROM MyTable
      WHERE action = 'bought'

      GROUP BY itemName
      ORDER BY boughtCount DESC
     )
ORDER BY boughtCount

编辑：根据评论中的精确度：

编辑2：这是在MSSQL中测试的，可能需要为HiveSQL调整一些语法。

SELECT TOP 1 itemId
FROM (
        -- Get the list of the top 3 items that have as many ItemsByUsers entries as distinct userIds 
        -- in the table, group by item and sort by sum of items bought descending.
        SELECT TOP 3 itemId, SUM(boughtCount) AS totalBought
        FROM (
              -- Get a list of the most bought items by item and user
              SELECT itemId, userId, COUNT(*) AS boughtCount
              FROM MyTable
              WHERE action = 'bought'
              GROUP BY itemId, userId
             ) AS ItemCountByUser
        GROUP BY itemId
        HAVING COUNT(*) = (SELECT COUNT(*) FROM (SELECT DISTINCT userId FROM MyTable) AS UserCount)
        ORDER BY totalBought DESC
     ) AS MostBought
ORDER BY totalBought

Answer 2

我的理解是，您想要显示任何用户3次或更多次购买的itemNames ....？

SELECT a.itemName FROM
    (SELECT 
        itemName AS itemName,
        sum(action) AS action
    FROM
        (SELECT
            a.itemName as itemName,
            CASE
                WHEN (action = 'bought')
                    THEN (1)
                ELSE (0)
            END AS action
        FROM yourTableName) AS a
    GROUP BY
        itemName) AS a
where action > 2;

我尚未对此进行测试......

如果这不是你的解决方案，请告诉我，以便我可以探索其他选择..

Answer 3

请尝试以下查询，列出所有用户购买的商品名称，并列在第3位

SQL / Hive查询查找所有用户购买的第三个不同项目？

3 个答案: