scala中关于数据框连接选择操作的NVL函数？

Question

I can join dataframes in scala like this and it works;

  df1.join(df2, df1("id") === df2("id"), "left").select(df1("id"),df2("name"))

I want to use nvl function on df2.name column like nvl(df2.name,"test")

How can I handle this with spark scala ?

thanks in advance

Answer 1

您可以使用 spark.sql.functions 中的 coalece 和 lit

df1.join(df2, df1("id") === df2("id"), "left").select(df1("id"),coalesce(df2("name"),lit("test")))