Pig Latin中的多个JOIN

Question

在HQL中，我们有

JOIN weather ON (weather.Year = flight.Year AND weather.Month = flight.Month and weather.Day=flight.DayofMonth)

在Pig Latin中，是否可以将其纳入一个查询？或者我必须单独进行并将它们组合起来？

Answer 1

可能会看到here：

  

您还可以加入多个密钥。在所有情况下，你必须拥有   相同数量的密钥，它们必须是相同或兼容的类型

示例：

weather = load '/weather/files/' as (Year,Month,Day,Fieldx);
flight = load '/flight/files/' as (Year,Month,Day,Fieldy);
jnd   = join weather by (Year,Month,Day), flight by (Year,Month,Day);