Standardizing color names
In the previous exercise, the DIFFERENCE() function was used to identify colors that closely matched our desired representation of the color GRAY. However, this approach retained a number of records where the vehicle_color value may or may not be gray. Specifically, the string GR (green) has the same Soundex code as the string GRAY. Fortunately, records with these vehicle_color values can be excluded from the set of records that should be changed.
In this exercise, you will assign a consistent gray vehicle_color value by identifying similar strings that represent the same color. Again, the fuzzystrmatch module has already been installed for you.
この演習はコースの一部です
Cleaning Data in PostgreSQL Databases
演習の手順
- Complete the
SETclause to assign'GRAY'as thevehicle_colorfor records with avehicle_colorvalue having a matching Soundex code to the Soundex code for'GRAY'. - Update the
WHEREclause of the subquery so that thesummons_numbervalues returned excludesummons_numbervalues from records with'GR'as thevehicle_colorvalue.
実践的なインタラクティブ演習
このサンプルコードを完成させて、この演習に挑戦してみましょう。
UPDATE
parking_violation
SET
-- Update vehicle_color to `GRAY`
___ = ___
WHERE
summons_number IN (
SELECT
summons_number
FROM
parking_violation
WHERE
DIFFERENCE(vehicle_color, 'GRAY') = 4 AND
-- Filter out records that have GR as vehicle_color
___ != ___
);