druid-docs-cn/having.md at 122bdda012b4fd614c670c063347fe1bee9f7fef

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Having过滤器(groupBy)

[!WARNING] Apache Druid支持两种查询语言： Druid SQL 和原生查询。该文档描述了原生查询中的一种查询方式。对于Druid SQL中使用的该种类型的信息，可以参考 SQL文档。

having语法用来通过对聚合后的值指定特定条件来决定从GroupBy的结果中返回符合条件的行，基本等价于SQL语法中的HAVING

Apache Druid支持下列类型的having语法

查询过滤器(Query Filters)

所有的Druid查询过滤器都可以被用来使用在查询体的Having部分中。一个查询过滤器的HavingSpec如下：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type" : "filter",
            "filter" : <any Druid query filter>
        }
}

例如，使用一个选择过滤器(selector filter)：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type" : "filter",
            "filter" : {
              "type": "selector",
              "dimension" : "<dimension>",
              "value" : "<dimension_value>"
            }
        }
}

对结果行的时间戳进行使用Having语法的时候也可以生效，如同在 "__time" 字段上使用过滤器。

数值过滤器(Numeric Filters)

最简单的having子句是数字过滤器。数字过滤器可以用作过滤器的更复杂布尔表达式的基过滤器。

下面是having子句数字筛选器的示例：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "greaterThan",
            "aggregation": "<aggregate_metric>",
            "value": <numeric_value>
        }
}

等于(equalTo)

equalTo过滤器根据指定的聚合后的值进行匹配，返回等于值的行，语法如下：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "equalTo",
            "aggregation": "<aggregate_metric>",
            "value": <numeric_value>
        }
}

这种方式等价于 HAVING <aggregate> > <value>

大于(Greater Than)

greaterThan过滤器根据指定的聚合后的值进行匹配，返回大于值的行，语法如下：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "greaterThan",
            "aggregation": "<aggregate_metric>",
            "value": <numeric_value>
        }
}

这种方式等价于 HAVING <aggregate> > <value>

小于(Less Than)

lessThan过滤器根据指定的聚合后的值进行匹配，返回大于值的行，语法如下：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "lessThan",
            "aggregation": "<aggregate_metric>",
            "value": <numeric_value>
        }
}

这种方式等价于 HAVING <aggregate> < <value>

维度选择过滤器(Dimension Selector Filter)

dimSelector

dimSelector过滤器根据维度值等于特定值来匹配行，语法如下：

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
       {
            "type": "dimSelector",
            "dimension": "<dimension>",
            "value": <dimension_value>
        }
}

逻辑表达式过滤器(Logical Expression Filters)

AND

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "and",
            "havingSpecs": [
                {
                    "type": "greaterThan",
                    "aggregation": "<aggregate_metric>",
                    "value": <numeric_value>
                },
                {
                    "type": "lessThan",
                    "aggregation": "<aggregate_metric>",
                    "value": <numeric_value>
                }
            ]
        }
}

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
            "type": "or",
            "havingSpecs": [
                {
                    "type": "greaterThan",
                    "aggregation": "<aggregate_metric>",
                    "value": <numeric_value>
                },
                {
                    "type": "equalTo",
                    "aggregation": "<aggregate_metric>",
                    "value": <numeric_value>
                }
            ]
        }
}

NOT

{
    "queryType": "groupBy",
    "dataSource": "sample_datasource",
    ...
    "having":
        {
        "type": "not",
        "havingSpec":
            {
                "type": "equalTo",
                "aggregation": "<aggregate_metric>",
                "value": <numeric_value>
            }
        }
}

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