Oracle提供了許多高級函數來處理復雜查詢,包括聚合函數、窗口函數、分析函數等。下面是一些常用的高級函數及其用法:
SELECT SUM(salary) AS total_salary
FROM employees;
SELECT employee_id, salary,
ROW_NUMBER() OVER (ORDER BY salary DESC) AS rank
FROM employees;
SELECT employee_id, hire_date, salary,
LAG(salary) OVER (ORDER BY hire_date) AS prev_salary
FROM employees;
SELECT employee_id, hire_date,
TO_CHAR(hire_date, 'YYYY-MM-DD') AS hire_date_str
FROM employees;
通過使用這些高級函數,可以更靈活地處理復雜查詢需求,提高查詢效率和可讀性。在實際應用中,根據具體情況選擇合適的高級函數來實現查詢功能。