根据其他数据框上的现有字段加入数据框

Question

嗨，我有具有以下结构的数据框，我想做的是从表Histoachat中获取网站应该在POS中的数据，而FRN应该是供应商DataFrame的ID码头应在表格中

 histoachat.printSchema()
        pos.printSchema()
        supplier.printSchema()
        article.printSchema()
        pos.printSchema()
    root
     |-- SITE: decimal(5,0) (nullable = false)
     |-- FRN: string (nullable = true)
     |-- CODA: string (nullable = true)
     |-- QT: decimal(38,0) (nullable = true)
     |-- PB: decimal(38,0) (nullable = true)
     |-- REMI: decimal(38,0) (nullable = true)
     |-- PNETTVA: decimal(38,0) (nullable = true)
     |-- SCH: decimal(38,0) (nullable = true)
    root
     |-- id: long (nullable = false)
    root
     |-- id: long (nullable = false)
    root
     |-- id: long (nullable = false)
    root
     |-- id: long (nullable = false)

在这里我仍然遇到外国密钥问题，最终数据框架将插入包含三个外国键网站的PostgreSQL表中，FRN和CODA

   val test_Pos = histoachat.select($"SITE" as "pos_id").except(pos.select("id").distinct())
     val supplier_Test = histoachat.select($"FRN" as "frn_id").except(supplier.select("id").distinct())
    val article_Test = histoachat.select($"CODA" as "art_id").except(article.select("id").distinct())
     val finalHistoachat = histoachat.except(exRows)

任何帮助谢谢在这里我得到的问题

非常感谢

Answer 1

我有一个昂贵的解决方案，即通过使用join

val finalHistoachat = histoachat.as("histo").join(pos.as("pos"), $"histo.SITE" === $"pos.id")
                                                .drop($"pos.id")
                                                .as("joined1")
                                                .join(supplier.as("sup"), $"joined1.FRN" === $"sup.id")
                                                .drop($"sup.id")
                                                .as("joined2")
                                                .join(article.as("art"), $"joined2.CODA" === $"art.id")
                                                .drop($"art.id")

我希望答案很有帮助，直到您获得一些灯光答案，这个答案应帮助您获得最终的数据框架