MYSQL：在單個查詢中計算按兩個不同條件分組的列的 SUM

Question

假設我有這些示例數據的簡化表結構：

id | duration_seconds (int) | is_billable (boolean)
1  | 100                    | false
2  | 500                    | true
3  | 100                    | false
4  | 150                    | true

是否可以從單個查詢中獲得這樣的結果？

total_duration | billable_duration | non_billable_duration
850            | 650               | 200

Answer 1

您可以使用條件聚合在一個查詢中獲取不同的總和：

SELECT SUM(duration_seconds ) AS total_duration,
       SUM(CASE WHEN is_billable THEN duration_seconds ELSE 0 END) AS billable_duration,
       SUM(CASE WHEN NOT is_billable THEN duration_seconds ELSE 0 END) AS non_billable_duration
FROM yourtable

輸出（對於您的樣本數據）

total_duration  billable_duration   non_billable_duration
850             650                 200

SQLFiddle 上的演示