摘要:要熟练使用 SQL 查询(Structured Query Language),你需要系统地从语法入门,到实战练习,再到性能优化与多表查询的掌握。下面是一条循序渐进、实战驱动的学习路径:
要熟练使用 SQL 查询(Structured Query Language),你需要系统地从语法入门,到实战练习,再到性能优化与多表查询的掌握。下面是一条循序渐进、实战驱动的学习路径:
✅ 示例:
SELECT name, age FROM students WHERE age > 18 ORDER BY age DESC;✅ 示例:
SELECT department, COUNT(*) AS num_employees FROM employees GROUP BY department HAVING COUNT(*) > 10;SELECT orders.id, customers.name FROM orders INNER JOIN customers ON orders.customer_id = customers.id;✅ 示例:
SELECT name FROM students WHERE age > (SELECT AVG(age) FROM students);ROW_NUMBER、RANK、DENSE_RANK、LAG、LEADOVER(PARTITION BY ... ORDER BY ...) 是关键语法✅ 示例:
SELECT name, department, RANK OVER(PARTITION BY department ORDER BY score DESC) AS dept_rank FROM employees;来源:数据分析精选