Aihua Xu created HIVE-10554:
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Summary: The examples on windows function doc page are not correct
Key: HIVE-10554
URL: https://issues.apache.org/jira/browse/HIVE-10554
Project: Hive
Issue Type: Bug
Components: Documentation
Reporter: Aihua Xu
In the following doc page for windowing functions,
https://cwiki.apache.org/confluence/display/Hive/LanguageManual+WindowingAndAnalytics
On the bottom of the page, we list two examples: LEAD(a) and LAG(a) for "rows
between".
{noformat}
LEAD using default 1 row lead and not specifying default value
SELECT a, LEAD(a) OVER (PARTITION BY b ORDER BY C ROWS BETWEEN CURRENT ROW AND
1 FOLLOWING)
FROM T;
LAG specifying a lag of 3 rows and default value of 0
SELECT a, LAG(a, 3, 0) OVER (PARTITION BY b ORDER BY C ROWS 3 PRECEDING)
FROM T;
{noformat}
Actually LEAD and LAG functions don't support window frames since it's always
relative to the current row. We can switch to functions like "first_value(),
count(*)", etc.
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