Head First PHP & MySQL（中文版）

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• It's possible to skip the php substr() function and limit the job description data in the SQL query itself.You use a very similar MySQL function called SUBSTRING() that accepts the same arguments as substr(). The only difference is that the starting index starts at 1 instead of 0.So grabbing the first 100 characters of the job description looks like this: SELECT SUBSTRING(job_description, 1, 100) FROM riskyjobs; (查看原文)

  修缘 2016-08-18 15:13:24

• Remember that our goal is to simplify the messy Mismatch queries with INNER JOIN.When an inner join involves matching columns with the same name, we can further simplify the query with the help of USING statement.The USING statement takes the place of ON in an INNER JOIN query, and requires the name of the column to be used in the match.Just make sure the column is named exactly the same in both tables.As an example, here's the Mismatch query again: SELECT mismatch_topic.topic_id, mismatch_category.name FROM mismatch_topic INNER JOIN mismatch_category USING (category_id) WHERE mismatch_topic.name = 'Horror movies' (查看原文)

  修缘 2016-08-18 17:28:30

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