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-- location_extract(streetAddressString, stateAbbreviation)
-- This function extracts a location name from the end of the given string.
-- The first attempt is to find an exact match against the place_lookup
-- table. If this fails, a word-by-word soundex match is tryed against the
-- same table. If multiple candidates are found, the one with the smallest
-- levenshtein distance from the given string is assumed the correct one.
-- If no match is found against the place_lookup table, the same tests are
-- run against the countysub_lookup table.
--
-- The section of the given string corresponding to the location found is
-- returned, rather than the string found from the tables. All the searching
-- is done largely to determine the length (words) of the location, to allow
-- the intended street name to be correctly identified.
CREATE OR REPLACE FUNCTION location_extract(fullStreet VARCHAR, stateAbbrev VARCHAR) RETURNS VARCHAR
AS $_$
DECLARE
location VARCHAR;
BEGIN
IF fullStreet IS NULL THEN
RETURN NULL;
END IF;
location := location_extract_place_exact(fullStreet, stateAbbrev);
IF location IS NULL THEN
location := location_extract_countysub_exact(fullStreet, stateAbbrev);
IF location IS NULL THEN
location := location_extract_place_fuzzy(fullStreet, stateAbbrev);
IF location IS NULL THEN
location := location_extract_countysub_fuzzy(fullStreet, stateAbbrev);
END IF;
END IF;
END IF;
RETURN location;
END;
$_$ LANGUAGE plpgsql;
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