我正在使用 MySQL。
我有一张表service_status：
id | service_id | service_status
----------------------------------------------------------------------
0 | 1001 | download_started
1 | 1001 | download_started
2 | 1002 | download_started
3 | 1002 | download_started
4 | 1002 | download_failed
5 | 1003 | download_started
6 | 1003 | download_failed
7 | 1003 | something_else
8 | 1003 | another_thing
我想查询所有service_ids，以及计算 数量download_started和数量的两个附加列download_failed：
id | service id | download_started | download_failed
----------------------------------------------------------------------
0 | 1001 | 2 | 0 …