我正在尝试构造一个Azure ServiceBus订阅规则，该规则将根据参数的subjectFilter数组属性的长度来使用相关过滤器或SQL过滤器。我尝试使用基于this answer的if和union来实现这一点。但是，看起来该对象是用所有属性构造的。例如，sql筛选器错误为“必须为相关性筛选器设置至少一个系统或用户属性”
这是我的代码（简化版）。

• copy变量包含用于每个订阅名称和filterProperties的属性，其中定义了filterType，并用作基本properties对象。
• 它还分别为sqlFilterProperties和correlationFilterProperties声明了一个单独的对象。
• sqlFilterProperties或correlationFilterProperties对象应与filterProperties联合以构造完整的properties。

{
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "resourceName": {
            "type": "string"
        },
        "topics": {
            "type": "array"
        },
        "subscriptionName": {
            "type": "string"
        }
    },
    "variables": {
        "apiVersion": "2018-01-01-preview",
        "copy": [
            {
                "name": "subscriptions",
                "count": "[length(parameters('topics'))]",
                "input": {
                    "name": "[concat(parameters('resourceName'), '/', parameters('topics')[copyIndex('subscriptions')].name, '/', parameters('subscriptionName'))]",
                    "filterProperties": {
                        "filterType": "[if(greater(length(parameters('topics')[copyIndex('subscriptions')].subjectFilter),1),'sqlFilter','correlationFilter')]"
                    },
                    "sqlFilterProperties": {
                        "sqlFilter": {
                            "sqlExpression": "[concat('sys.subject in (''',join(parameters('topics')[copyIndex('subscriptions')].subjectFilter,''','''), ''')')]",
                            "requiresPreprocessing": false
                        }
                    },
                    "correlationFilterProperties": {
                        "correlationFilter": {
                            "subject": "[parameters('topics')[copyIndex('subscriptions')].subjectFilter[0]]",
                            "requiresPreprocessing": false
                        }
                    }
                }
            }
        ]
    },
    "resources": [
        {
            "type": "Microsoft.ServiceBus/namespaces/topics/subscriptions/rules",
            "apiVersion": "[variables('apiVersion')]",
            "copy": {
                "name": "subscriptionFilters",
                "count": "[length(parameters('topics'))]"
            },
            "name": "[concat(variables('subscriptions')[copyIndex()].name, '/subject')]",
            "properties": "[union(variables('subscriptions')[copyIndex()].filterProperties, if(startsWith(variables('subscriptions')[copyIndex()].filterProperties.filterType, 'sql'), variables('subscriptions')[copyIndex()].sqlFilterProperties, variables('subscriptions')[copyIndex()].correlationFilterProperties) )]"
        }
    ]
}

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