求多个库的数量总和sql

SELECT SUM(num) FROM
 (
        SELECT 'osc1' as type,COUNT(*) AS num FROM fi_osc1.schedule_task_8
 UNION ALL
 SELECT 'osc2' as type,COUNT(*) AS num FROM fi_osc2.schedule_task_8
 UNION ALL
 SELECT 'osc3' as type,COUNT(*) AS num FROM fi_osc3.schedule_task_8
 UNION ALL
 SELECT 'osc4' as type,COUNT(*) AS num FROM fi_osc4.schedule_task_8
 UNION ALL
 SELECT 'osc5' as type,COUNT(*) AS num FROM fi_osc5.schedule_task_8
 UNION ALL
 SELECT 'osc6' as type,COUNT(*) AS num FROM fi_osc6.schedule_task_8
 UNION ALL
 SELECT 'osc7' as type,COUNT(*) AS num FROM fi_osc7.schedule_task_8
 UNION ALL
 SELECT 'osc8' as type,COUNT(*) AS num FROM fi_osc8.schedule_task_8


 ) c