sql - 多个选择查询合并为一个查询

Question

我需要将多个 select 语句分组到一个查询和多个列中

我已经尝试过使用 UNION，但它导致我的一个选择丢失(可能误用它)

SELECT COUNT(*) AS EMERGENCIA FROM Incidentes WHERE Prioridad_Real = 'Emergencia' AND Estado = 'Resuelto a Tiempo'
AND Fecha_Asigna >= '2013-08-22 13:30:00.000' and Fecha_Resul <= '2013-08-23 11:16:00.000'

SELECT COUNT(*) AS ALTA FROM Incidentes WHERE Prioridad_Real = 'Alta' AND Estado = 'Resuelto a Tiempo' 
AND Fecha_Asigna >= '2013-08-22 13:30:00.000' and Fecha_Resul <= '2013-08-23 11:16:00.000'

SELECT COUNT(*) AS MEDIA FROM Incidentes WHERE Prioridad_Real = 'Media' AND Estado = 'Resuelto a Tiempo'
AND Fecha_Asigna >= '2013-08-22 13:30:00.000' and Fecha_Resul <= '2013-08-23 11:16:00.000'

SELECT COUNT(*) AS BAJA FROM Incidentes WHERE Prioridad_Real = 'Baja' AND Estado = 'Resuelto a Tiempo'
AND Fecha_Asigna >= '2013-08-22 13:30:00.000' and Fecha_Resul <= '2013-08-23 11:16:00.000'

预期结果:

Answer 1

尝试使用以下查询:

SELECT SUM(CASE WHEN Prioridad_Real = 'Emergencia' THEN 1 ELSE 0 END) as EMERGENCIA,
       SUM(CASE WHEN Prioridad_Real = 'Alta' THEN 1 ELSE 0 END) as ALTA,
       SUM(CASE WHEN Prioridad_Real = 'Media' THEN 1 ELSE 0 END) as MEDIA,
       SUM(CASE WHEN Prioridad_Real = 'Baja' THEN 1 ELSE 0 END) as BAJA
FROM   Incidentes WHERE  Estado = 'Resuelto a Tiempo' 
AND Fecha_Asigna >= '2013-08-22 13:30:00.000' and Fecha_Resul <= '2013-08-23 11:16:00.000'