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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/UDF" by DaveBrondsema
Date Mon, 13 Dec 2010 19:07:16 GMT
Dear Wiki user,

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The "Hive/LanguageManual/UDF" page has been changed by DaveBrondsema.
The comment on this change is: add collect_set.


  ||double ||percentile_approx(col, p [, B]) || Returns an approximate p^th^ percentile of
a numeric column (including floating point types) in the group. The B parameter controls approximation
accuracy at the cost of memory. Higher values yield better approximations, and the default
is 10,000. When the number of distinct values in col is smaller than B, this gives an exact
percentile value. ||
  ||array<double> || percentile_approx(col, array(p,,1,, [, p,,2,,]...) [, B]) || Same
as above, but accepts and returns an array of percentile values instead of a single one. ||
  ||array<struct `{'x','y'}`>|| histogram_numeric(col, b) || Computes a histogram of
a numeric column in the group using b non-uniformly spaced bins. The output is an array of
size b of double-valued (x,y) coordinates that represent the bin centers and heights ||
+ ||array ||collect_set(col) ||Returns a set of objects with duplicate elements eliminated
  == Built-in Table-Generating Functions (UDTF) ==
  <<Anchor(UDTF)>> Normal user-defined functions, such as concat(), take in a
single input row and output a single output row. In contrast, table-generating functions transform
a single input row to multiple output rows. 

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