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Posted to dev@pig.apache.org by "Alan Gates (JIRA)" <ji...@apache.org> on 2009/06/02 21:35:08 UTC
[jira] Commented: (PIG-826) DISTINCT as "Function/Operator" rather
than statement/operator - High Level Pig
[ https://issues.apache.org/jira/browse/PIG-826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12715639#action_12715639 ]
Alan Gates commented on PIG-826:
--------------------------------
It can be done like this:
{code}
Logs = load 'log' using PigStorage()
as ( user: chararray, country: chararray, url: chararray);
Grouped = group Logs all;
foreach Grouped {
duser = distinct Logs.user;
dcountry = distinct Logs.country;
durl = distinct Logs.url;
generate COUNT(duser), COUNT(dcountry), COUNT(durl);
};
{code}
> DISTINCT as "Function/Operator" rather than statement/operator - High Level Pig
> -------------------------------------------------------------------------------
>
> Key: PIG-826
> URL: https://issues.apache.org/jira/browse/PIG-826
> Project: Pig
> Issue Type: New Feature
> Reporter: David Ciemiewicz
>
> In SQL, a user would think nothing of doing something like:
> {code}
> select
> COUNT(DISTINCT(user)) as user_count,
> COUNT(DISTINCT(country)) as country_count,
> COUNT(DISTINCT(url) as url_count
> from
> server_logs;
> {code}
> But in Pig, we'd need to do something like the following. And this is about the most
> compact version I could come up with.
> {code}
> Logs = load 'log' using PigStorage()
> as ( user: chararray, country: chararray, url: chararray);
> DistinctUsers = distinct (foreach Logs generate user);
> DistinctCountries = distinct (foreach Logs generate country);
> DistinctUrls = distinct (foreach Logs generate url);
> DistinctUsersCount = foreach (group DistinctUsers all) generate
> group, COUNT(DistinctUsers) as user_count;
> DistinctCountriesCount = foreach (group DistinctCountries all) generate
> group, COUNT(DistinctCountries) as country_count;
> DistinctUrlCount = foreach (group DistinctUrls all) generate
> group, COUNT(DistinctUrls) as url_count;
> AllDistinctCounts = cross
> DistinctUsersCount, DistinctCountriesCount, DistinctUrlCount;
> Report = foreach AllDistinctCounts generate
> DistinctUsersCount::user_count,
> DistinctCountriesCount::country_count,
> DistinctUrlCount::url_count;
> store Report into 'log_report' using PigStorage();
> {code}
> It would be good if there was a higher level version of Pig that permitted code to be written as:
> {code}
> Logs = load 'log' using PigStorage()
> as ( user: chararray, country: chararray, url: chararray);
> Report = overall Logs generate
> COUNT(DISTINCT(user)) as user_count,
> COUNT(DISTINCT(country)) as country_count,
> COUNT(DISTINCT(url)) as url_count;
> store Report into 'log_report' using PigStorage();
> {code}
> I do want this in Pig and not as SQL. I'd expect High Level Pig to generate Lower Level Pig.
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