查找重复值oracle SQL

Question

我正在尝试编写一个 oracle SQL 语句来告诉我对每个属性进行了多少调查。

我有一张桌子 - property:

还有一个在这里 - survey:

我使用下面的语句来完成此操作，但从结果表中可以看出，它仍然将重复项显示为单独的条目，因此计数函数只计数 1。

SELECT property.property_id, property.property_address_first_line, survey.survey_id, survey.date_of_viewing, count( property.property_id) as "number_of_surveys"        
    from property
    inner join survey
    on (survey.property_id = property.property_id)
    group by property.property_id, property.property_address_first_line, survey.survey_id, survey.date_of_viewing
    order by property.property_id;

非常感谢

Answer 1

如果您想知道特定属性 ID 进行了多少次调查，您需要从查询中删除 survey.survey_id, survey.date_of_viewing 字段

SELECT property.property_id, property.property_address_first_line, count( survey.survey_id) as "number_of_surveys"        
    from property
    left outer join survey
    on (survey.property_id = property.property_id)
    group by property.property_id, property.property_address_first_line
    order by property.property_id;