如何在一个查询中获取子集的计数以及总计数？

如果启用始终为1或0,则可以执行以下操作:

SELECT 
   COUNT(*) as total_count,
   SUM(enabled) as enabled_count
 FROM widget

如果它是另一个值,也许:

SELECT
   COUNT(*) as total_count,
   SUM( CASE WHEN enabled in ('enabled value 1', 'enabled value 2') 
        THEN 1
        ELSE 0
        END
      ) as enabled_count
FROM widget