MYSQL:计算一个查询中按两个不同条件分组的列的总和

可以使用条件聚合在一个查询中获取不同的和:

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

输出(用于示例数据)

total_duration  billable_duration   non_billable_duration
850             650                 200

Demo on SQLFiddle