FAILED: SemanticException Cartesian products are disabled for safety reasons. If you know what you are doing, please sethive.strict.checks.cartesian.product to false and that hive.mapred.mode is not set to 'strict' to proceed. Note that if you may get errors or incorrect results if you make a mistake while using some of the unsafe features.
出于安全原因，SemanticException笛卡尔产品被禁用。如果你知道自己在做什么，请将sethive.strict.checks.cartesian.product设置为false并且hive.mapred.mode未设置为”strict“以继续。请注意，如果您在使用某些不安全功能时犯了错误，可能会得到错误或不正确的结果。
我这里是在Hive中进行的。
解决方法：from a,b -> from a inner join b
