SQL - 如何使用来自同一个表的多个查询执行嵌套 SELECT？答案

【问题标题】：SQL - How to perform a nested SELECT with multiple queries from the same table?SQL - 如何使用来自同一个表的多个查询执行嵌套 SELECT？
【发布时间】：2019-07-16 16:03:21
【问题描述】：

我编写了一个嵌套选择查询，它工作正常。

select user_id, transaction_id, t_timestamp 
from (
    select *, row_number() over (partition by (user_id || '*' || transaction_id) order by f_time asc) rownum
    from transactionMetricsView
    where metric_1 in (select metric_value 
                       from main.metrics 
                       where metric_key = 'metric_type_1')
)
where rownum = 1

但main.metrics 表也有一个m_date 字段，所以我需要检查日期是否在给定范围内。但我不确定如何正确实施。

我认为它应该类似于下面的查询，但现在更像是一个伪代码。

select user_id, transaction_id, t_timestamp 
from (
     select *, row_number() over (partition by (user_id || '*' || transaction_id) order by f_time asc) rownum
     from transactionMetricsView
     where metric_1 in (select metric_value 
                        from main.metrics 
                        where metric_key = 'metric_type_1') 
         and (select m_date 
              from main.metrics between $startDate and $endDate)
)
where rownum = 1

【问题讨论】：

样本数据和期望的结果会有所帮助。适当的数据库标签也是如此。
标记适当的数据库名称。还要添加示例数据和预期输出。

标签： sql postgresql select

【解决方案1】：

这可能有效：

 select user_id, transaction_id, t_timestamp from (select *, row_number() over (partition by (user_id || '*' || transaction_id) order by f_time asc) rownum
 from transactionMetricsView
 where metric_1 in (select metric_value 
                    from main.metrics 
                    where metric_key = 'metric_type_1'
                      and m_date between $startDate and $endDate
                    )
  and rownum = 1

【讨论】：