hadoop - Pig Latin 中 AVG() 函数的问题

Question

我正在尝试生成数据集中列出的性能 (double) 的 AVG()。我收到一个 ERROR 1066: Unable to open iterator for alias TEST 异常，我认为这是因为 TEST 是空的并且无法迭代。

代码:

flat_bus = FOREACH buss GENERATE near, name, FLATTEN(categories) AS category, stars;

bus_grouped = GROUP flat_bus BY category;

category_avg = FOREACH bus_grouped GENERATE group as grp, AVG(bus_grouped.stars);

TEST = LIMIT category_avg 10;

DUMP TEST;

我测试了群组功能，它成功转储如下所示:

Answer 1

应该从 flat_bus 获得星星

category_avg = FOREACH bus_grouped GENERATE group as grp, AVG(flat_bus.stars);