在Oracle中，可以使用OVER()函數和分析函數來優化查詢。分析函數可以在查詢結果中進行分析和計算，而無需使用子查詢或連接操作。以下是一些使用OVER()優化查詢的示例：
SELECT
ROW_NUMBER() OVER(ORDER BY column_name) AS row_num,
column_name
FROM table_name;
SELECT
RANK() OVER(ORDER BY column_name) AS rank,
column_name
FROM table_name;
SELECT
column_name,
SUM(column_name) OVER(ORDER BY column_name) AS cumulative_sum
FROM table_name;
SELECT
column_name,
LAG(column_name) OVER(ORDER BY column_name) AS previous_value,
LEAD(column_name) OVER(ORDER BY column_name) AS next_value
FROM table_name;
通過使用OVER()函數和分析函數，可以更高效地進行數據分析和報表生成，而無需使用多個子查詢或連接操作。這可以大大提高查詢性能和可讀性。
