SQL 风格

SQL 中级

Jasmin Ludolf

Data Science Content Developer, DataCamp

SQL 格式化

格式化非必需
但缺少格式会带来问题

select title, release_year, country from films limit 3

|title                                           |release_year|country|
|------------------------------------------------|------------|-------|
|Intolerance: Love's Struggle Throughout the Ages|1916        |USA    |
|Over the Hill to the Poorhouse                  |1920        |USA    |
|The Big Parade                                  |1925        |USA    |

最佳实践

SELECT title, release_year, country
FROM films 
LIMIT 3;

|title                                           |release_year|country|
|------------------------------------------------|------------|-------|
|Intolerance: Love's Struggle Throughout the Ages|1916        |USA    |
|Over the Hill to the Poorhouse                  |1920        |USA    |
|The Big Parade                                  |1925        |USA    |

关键词大写
分行书写

风格指南

SELECT  
    title, 
    release_year, 
    country
FROM films 
LIMIT 3;

|title                                           |release_year|country|
|------------------------------------------------|------------|-------|
|Intolerance: Love's Struggle Throughout the Ages|1916        |USA    |
|Over the Hill to the Poorhouse                  |1920        |USA    |
|The Big Parade                                  |1925        |USA    |

风格指南

Holywell 的风格指南: https://www.sqlstyle.guide/

一串涂鸦变成直线的序列

编写清晰可读的代码

分号

SELECT title, release_year, country
FROM films 
LIMIT 3;

最佳实践
更易在不同 SQL 方言间迁移
表示查询结束

处理非标准字段名

用 release year 代替 release_year
将非标准字段名用双引号括起

SELECT title, "release year", country
FROM films 
LIMIT 3;

为何要格式化？

便于协作
清晰可读
专业美观
更易理解
更易调试

Vamos praticar!

SQL 中级