Question

我正在尝试编写一个猪拉丁语脚本来提取我已过滤的数据集的计数。

到目前为止，这是脚本：

/* scans by title */

scans           = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans    = FILTER scans BY (title MATCHES 'proactiv');
scancount       = FOREACH productscans GENERATE COUNT($0);
DUMP scancount;

出于某种原因，我收到错误：

无法将org.apache.pig.builtin.COUNT的匹配函数推断为多个或不适合。请使用明确的演员。

我在这里做错了什么？我假设它与我传入的字段类型有关，但我似乎无法解决这个问题。

TIA，杰森

Answer 1

这是你正在寻找的东西（所有人都将所有东西放在一个袋子中，然后计算物品）：

scans           = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans    = FILTER scans BY (title MATCHES 'proactiv');
grouped         = GROUP productscans ALL;
count           = FOREACH grouped GENERATE COUNT(productscans);
dump count;

Answer 2

COUNT 需要先前的GROUP ALL语句用于全局计数，而GROUP BY语句用于组计数。

您可以使用以下任何一项：

scans           = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans    = FILTER scans BY (title MATCHES 'proactiv');
grouped         = GROUP productscans ALL;
count           = FOREACH grouped GENERATE COUNT(productscans);
DUMP scancount;

或者

scans           = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans    = FILTER scans BY (title MATCHES 'proactiv');
grouped         = GROUP productscans ALL;
count           = FOREACH grouped GENERATE COUNT($1);
DUMP scancount;

Answer 3

也许

/* scans by title */

scans           = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans    = FILTER scans BY (title MATCHES 'proactiv');
scancount       = FOREACH productscans GENERATE COUNT(productscans);
DUMP scancount;

无法推断COUNT函数

3 个答案: