Consulta MySQL Sumar distintas tablas

[facundojr07]

Buenos dias,

Les hago la siguiente consulta. Lo que quiero generer es una suma de columnas en distintas tablas.

He generado el siguiente código y me funciona

Código MySQL:

SELECT START, SUM(Mbps_DL_hpps) AS Suma_total, SUM(Mbps_UL_hpps) AS Sum_total2
FROM(
SELECT START,
SUM(trafico_datos_R99_DL+trafico_datos_HSDPA)*8/3600 AS Mbps_DL_hpps,
SUM(trafico_datos_R99_UL+trafico_datos_HSUPA)*8/3600 AS Mbps_UL_hpps
FROM Estadisticas_UMTS.RAN_UCELL_hpps 
WHERE START>=('2014-03-01') GROUP BY START
UNION ALL
SELECT START,
SUM(DL_PS_R99_Bytes+HSDPA_RLC_Traffic)/1024/1024*8/3600 AS Mbps_DL_hpps, 
SUM(UL_PS_R99_Bytes+HSUPA_RLC_Traffic)/1024/1024*8/3600 AS Mbps_UL_hpps
FROM Estadisticas_UMTS.KPI_Trafico_cell_hpps  
WHERE START>=('2014-03-01') GROUP BY START 
)
X GROUP BY START
 

Pero como son varias Tablas las que quiero sumar, he generado el siguiente codigo que no me funciona:

Código MySQL:

SELECT START, SUM(Erlangs_voz_hpcs) AS Suma_total, SUM(Mbps_DL_hpps) AS Suma_total, SUM(Mbps_UL_hpps) AS Sum_total2
FROM(
SELECT START, SUM(trafico_voz) AS Erlangs_voz_hpcs
FROM Estadisticas_UMTS.RAN_UCELL_hpcs
WHERE START>=('2014-03-01') GROUP BY START
UNION
SELECT START, SUM(AMR_Traffic) AS Erlangs_voz_hpcs
FROM Estadisticas_UMTS.KPI_Trafico_cell_hpcs
WHERE START>=('2014-03-01') GROUP BY START
UNION 
SELECT START,
SUM(trafico_datos_R99_DL+trafico_datos_HSDPA)*8/3600 AS Mbps_DL_hpps,
SUM(trafico_datos_R99_UL+trafico_datos_HSUPA)*8/3600 AS Mbps_UL_hpps
FROM Estadisticas_UMTS.RAN_UCELL_hpps 
WHERE START>=('2014-03-01') GROUP BY START
UNION
SELECT START,
SUM(DL_PS_R99_Bytes+HSDPA_RLC_Traffic)/1024/1024*8/3600 AS Mbps_DL_hpps, 
SUM(UL_PS_R99_Bytes+HSUPA_RLC_Traffic)/1024/1024*8/3600 AS Mbps_UL_hpps
FROM Estadisticas_UMTS.KPI_Trafico_cell_hpps  
WHERE START>=('2014-03-01') GROUP BY START
)
GROUP BY START
 

La consulta es cual es mi error en la segunda consulta que no devuelve resultados.

Muchas gracias. Saludos.