25 lines
716 B
MySQL
25 lines
716 B
MySQL
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--
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-- Calculate the equal interval bins for a given column
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--
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-- @param in_array An array of numbers to determine the best
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-- bin boundary
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--
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-- @param breaks The number of bins you want to find.
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--
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--
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-- Returns: upper edges of bins
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--
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--
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CREATE OR REPLACE FUNCTION @extschema@.CDB_EqualIntervalBins ( in_array anyarray, breaks INT ) RETURNS anyarray as $$
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WITH stats AS (
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SELECT min(e), (max(e)-min(e))/breaks AS del
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FROM (SELECT unnest(in_array) e) AS p)
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SELECT array_agg(bins)
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FROM (
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SELECT min + generate_series(1,breaks)*del AS bins
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FROM stats) q;
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$$ LANGUAGE SQL IMMUTABLE PARALLEL SAFE;
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DROP FUNCTION IF EXISTS @extschema@.CDB_EqualIntervalBins( numeric[], integer);
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