在SQL Server中进行透视和分组

Question

我想做一个数据透视表来显示每个类别和每个客户的销售量，类别表是这样的：

code     |  name
-----------------------
100000   | ILUMINACION
980101   | MUEBLES ACCESORIOS DECORATIVO
980102   | MUEBLES ACCESORIOS INTERIOR
980103   | MUEBLES ACCESORIOS ZOCALO

当我对categorys表的所有元素进行简单的数据透视时，所有方法都可以正常工作，但是该表具有近600个不同的类别，因此结果不是很可读，现在我想要的是将2个第一位数字进行分组，结果将是是这样的：ILUMINACION，MATERIAL ELECTRICO，MUEBLES，ELECTRODOMESTICOS ...，这样做将减少类别，使枢轴更易读，我尝试在by子句中放入group by，但是给我错误提示“子查询返回了多个值”。

这是我的代码：

---编辑----我试图尽可能简化

首先选择，并具有枢轴的总和（这不是问题）

select cliente,
(
select CASE WHEN cliente!='' then max(c.nombre) else 'CONTADO' end 
from CLIENTES c where c.nif=cliente
),
sum([APARELLAJE MEDIA TENSION_2015]) as [APARELLAJE MEDIA TENSION_2015],
sum([APARELLAJE MEDIA TENSION_2016]) as [APARELLAJE MEDIA TENSION_2016], 
sum([AUTOMATIZACION_2015]) as [AUTOMATIZACION_2015],
sum[AUTOMATIZACION_2016]) as [AUTOMATIZACION_2016],
sum([CANALIZACION_2015]) as [CANALIZACION_2015], 
sum([CANALIZACION_2016]) as [CANALIZACION_2016],
sum([COMPUESTOS_2015]) as [COMPUESTOS_2015], 
sum([COMPUESTOS_2016]) as [COMPUESTOS_2016],
sum([CONDUCTOR_2015]) as [CONDUCTOR_2015], 
sum([CONDUCTOR_2016]) as [CONDUCTOR_2016],
sum([CONEXION_2015]) as [CONEXION_2015], 
sum([CONEXION_2016]) as [CONEXION_2016],
sum([ELECTRODOMESTICOS_2015]) as [ELECTRODOMESTICOS_2015],
sum([ELECTRODOMESTICOS_2016]) as [ELECTRODOMESTICOS_2016],
sum([ENVOLVENTES_2015]) as [ENVOLVENTES_2015],
sum([ENVOLVENTES_2016]) as [ENVOLVENTES_2016],
sum([HERRAMIENTAS_2015]) as [HERRAMIENTAS_2015], 
sum([HERRAMIENTAS_2016]) as [HERRAMIENTAS_2016],
sum([ILUMINACION_2015]) as [ILUMINACION_2015], 
sum([ILUMINACION_2016]) as [ILUMINACION_2016],
sum([INSTRUMENTACION_2015]) as [INSTRUMENTACION_2015], 
sum([INSTRUMENTACION_2016]) as [INSTRUMENTACION_2016],
sum([MATERIAL DE INSTALACION_2015]) as [MATERIAL DE INSTALACION_2015],
sum([MATERIAL DE INSTALACION_2016]) as [MATERIAL DE INSTALACION_2016],
sum([PEQUEÑO MATERIAL_2015]) as [PEQUEÑO MATERIAL_2015], 
sum([PEQUEÑO MATERIAL_2016]) as [PEQUEÑO MATERIAL_2016],
sum([PROTECCION MANDO Y MEDIDA_2015]) as [PROTECCION MANDO Y MEDIDA_2015],
sum([PROTECCION MANDO Y MEDIDA_2016]) as [PROTECCION MANDO Y MEDIDA_2016],
sum([VARIOS_2015]) as [VARIOS_2015], sum([VARIOS_2016]) as [VARIOS_2016]

这是问题的核心

from
(
  select c.nif cliente, lac.ImporteLimpio suma,
  (
    SELECT DISTINCT
     (
      select case when ca.Codigo like '97%' then 'HERRAMIENTAS'
      else ca.Nombre end from CodigosEstadisticos_ARTICULOS ca
      where ca.Codigo=substring(cea.Codigo,1,2)+'0000'
     )
  +'_'+cast(YEAR(acc.fecalb)as varchar(100))
  from ALBARAN_CLIENTE acc,CodigosEstadisticos_ARTICULOS cca
  group by substring(cca.Codigo,1,2),acc.fecalb
  ) AS SalesRegion

from ALBARAN_CLIENTE ac join LINEAS_ALBARAN_CLIENTE lac on
c.codalb=lac.codalb join ARTICULOS a on a.codart=lac.codart join 
CodigosEstadisticos_ARTICULOS cea on cea.Codigo=a.codigoEstadistico
join CLIENTES c on c.codcli=ac.codcli 
where month(ac.fecalb)<month(getdate()) and(year(ac.fecalb)=year(getdate())
or year(ac.fecalb)=year(getdate())-1

)as p

PIVOT的一部分（我认为这里没有任何问题）

PIVOT
(
SUM(suma) FOR SalesRegion IN
([APARELLAJE MEDIA TENSION_2015],[APARELLAJE MEDIA TENSION_2016],
[AUTOMATIZACION_2015],[AUTOMATIZACION_2016],[CANALIZACION_2015],
CANALIZACION_2016], [COMPUESTOS_2015],[COMPUESTOS_2016],[CONDUCTOR_2015],
CONDUCTOR_2016],[CONEXION_2015],[CONEXION_2016],[ELECTRODOMESTICOS_2015],
[ELECTRODOMESTICOS_2016],[ENVOLVENTES_2015],[ENVOLVENTES_2016],
HERRAMIENTAS_2015],[HERRAMIENTAS_2016],[ILUMINACION_2015],
[ILUMINACION_2016],[INSTRUMENTACION_2015],[INSTRUMENTACION_2016],
[MATERIAL DE INSTALACION_2015],[MATERIAL DE INSTALACION_2016],
[PEQUEÑO MATERIAL_2015],[PEQUEÑO MATERIAL_2016],
[PROTECCION MANDO Y MEDIDA_2015],[PROTECCION MANDO Y MEDIDA_2016],
VARIOS_2015],[VARIOS_2016])
) AS pivottable group by cliente;