我有以下查询：
SELECT DISTINCT Summed, ROW_NUMBER () OVER (order by Summed desc) as Rank from table1
我必须在Apache Beam（beamSql）中编写它。以下是我的代码：
PCollection<BeamRecord> rec_2_part2 = rec_2.apply(BeamSql.query("SELECT DISTINCT Summed, ROW_NUMBER(Summed) OVER (ORDER BY Summed) Rank1 from PCOLLECTION "));
但我收到以下错误：
引起：java.lang.UnsupportedOperationException：运算符：ROW_NUMBER尚不支持！
知道如何在beamSql中实现ROW_NUMBER（）吗？
答案 0 :(得分：1)
以下是一种不使用let json: [String: Any] = ["from": "Mailgun Sandbox <(postmaster@sandbox(mySandBoxAddressKey).mailgun.org)>", "to": "(myPersonalMailAddress)@gmail.com", "subject": "test", "text": "Nochmal test"]
let jsonData = try? JSONSerialization.data(withJSONObject: json)
request.httpBody = jsonData
即可近似当前查询的方法：
ROW_NUMBER基本思想是首先使用子查询来获取仅具有不同SELECT
t1.Summed,
(SELECT COUNT(*) FROM (SELECT DISTINCT Summed FROM table1) t2
WHERE t2.Summed >= t1.Summed) AS Rank
FROM
(
SELECT DISTINCT Summed
FROM table1
) t1
值的表。然后，使用相关子查询来模拟行号。这不是一种非常有效的方法，但如果Summed不可用，那么你就会遇到一些替代方法。
答案 1 :(得分：0)
适用于上述查询的解决方案：
PCollection<BeamRecord> rec_2 = rec_1.apply(BeamSql.query("SELECT max(Summed) as maxed, max(Summed)-10 as least, 'a' as Dummy from PCOLLECTION"));