Philip (flip) Kromer created PIG-3941:
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Summary: Piggybank's Over UDF returns an output schema with named
fields
Key: PIG-3941
URL: https://issues.apache.org/jira/browse/PIG-3941
Project: Pig
Issue Type: Improvement
Components: piggybank
Reporter: Philip (flip) Kromer
Priority: Minor
With attached patch, if Over is constructed with a colon-delimited string like
'bob:int', the first part is used to set the return field's name and the second
part its type. Otherwise, if a type is given the name of the return field is
set to 'result'.
{code}
cities = LOAD 'us_city_pops.tsv' AS (city:chararray, state:chararray, pop:int);
DEFINE IOver
org.apache.pig.piggybank.evaluation.Over('state_rk:int');
ranked = FOREACH(GROUP cities BY state) {
c_ord = ORDER cities BY pop DESC;
GENERATE FLATTEN(Stitch(c_ord,
IOver(c_ord, 'rank', -1, -1, 2))); -- beginning (-1) to end (-1) on third
field (2)
};
DESCRIBE ranked;
-- ranked: {stitched::city: chararray,stitched::state: chararray,stitched::pop:
int,stitched::state_rk: int}
DUMP ranked;
-- ...
-- (Nashville,Tennessee,609644,2)
-- (Houston,Texas,2145146,1)
-- (San Antonio,Texas,1359758,2)
-- (Dallas,Texas,1223229,3)
-- (Austin,Texas,820611,4)
-- ...
{code}
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