将varchar值'I'转换为数据类型int时转换失败

Question

我有这个查询，当我执行它时会出现以下错误。

  

将varchar值'I'转换为数据类型int

时转换失败

该查询用于获取帐户状态客户的报告。软件中的模块是应收账款。

SELECT * 
FROM (
    SELECT Id_Cliente,
           TipoDeDocumento AS Id_Tipo,
           iif ( TipoDeDocumento in ('1','3','4'), 'Factura', 'Nota de Credito' ) AS Tipo,
           Movi_CartaPorte.Id_CartaPorte,
           Movi_CartaPorte.Folio,
           iif ( TipoDeDocumento in ('1','3','4'), Total, NULL) AS Cargo,
           iif ( TipoDeDocumento in ('2'), Total, NULL) AS Abono,
           Total,
           Fecha 
    FROM Movi_CartaPorte
    WHERE Id_StatusCartaPorte <> 100  
    AND 1 = 1

    UNION
    SELECT  Id_Cliente,
            1000 AS Id_Tipo, 
            'DEPÓSITO' AS Tipo,
            Id_CartaPorte,
            Descripcion AS Folio ,
            NULL AS Cargo,
            Importe AS Abono,
            Importe AS Total,
            Fecha 
    FROM Movi_CartaPorteCobranza 
    WHERE 1 = 1

) AS tabla 
ORDER BY Fecha