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非構造化テキストの探索

The description column of evanston311 has the details of the inquiry, while the category column groups inquiries into different types. How well does the category capture what's in the description?

LIKE and ILIKE queries will help you find relevant descriptions and categories. Remember that with LIKE queries, you can include a % on each side of a word to find values that contain the word. For example:

SELECT category
  FROM evanston311
 WHERE category LIKE '%Taxi%';

% matches 0 or more characters.

Building up the query through the steps below, find inquires that mention trash or garbage in the description without trash or garbage being in the category. What are the most frequent categories for such inquiries?

この演習はコースの一部です

SQLによる探索的データ分析

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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。

-- Count rows
SELECT ___
  FROM evanston311
 -- Where description includes trash or garbage
 WHERE ___ ___ ___
    ___ ___ ___ ___;
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