如何避免“无法在包含聚合或子查询的表达式上执行聚合函数”错误

Question

我正在运行此查询：

SELECT DISTINCT
    SUM(CASE WHEN b.CODNAT IN (SELECT item 
                               FROM fnMAS_Parametro_para_Lista('CON_SPED_FISCAL_CFOPS_BLOCO_C_FORA')) 
                THEN 0 EKSE ROUND(ISNULL(10, 0), 2) 
        END)
FROM
    ##tmpARPCO a
INNER JOIN
    ARPCO_ITENS_TOTALIZADORES b ON (b.numped = a.numped 
                                    AND b.seqped = a.seqped 
                                    AND b.tipo = 'P')
INNER JOIN
    ArEmpresa c ON (c.codempresa = a.codempresa)
INNER JOIN 
    ArNat d ON (d.codnat = b.codnat)
WHERE 
    1=1                       
    AND a.ESPEC IN ('NFE', 'NF', 'NFCE', 'NFA', 'NFFA', 'NFSE')  
    AND a.MODNF IN ('01', '1B', '04', '55', '65')                     
    AND a.datentr BETWEEN '20180401' AND '20180430' 
GROUP BY
    a.codcad, a.numnf, a.datentr, b.sittrib

但是我收到以下消息：

  

无法对包含聚合或子查询的表达式执行聚合功能

您可以看到的函数仅从表中返回一个代码字符串列表。如何解决该问题？

非常感谢您的帮助和时间

亚历山大（Alexandre）