在SQL条件下需要帮助

Question

假设我有两个表lpn和lpn_detail 如果我们在lpn表中使用lpn_id，我们只会得到一条记录。 如果我们在lpn_detail表中使用lpn_id，我们将得到多个记录，或者我们只能得到一条记录。

当我们加入这两个表时，我需要一个条件，其中Lpn_Detail的多条记录只应该作为结果获取。

select * from lpn inner join LPN_DETAIL 
on lpn.lpn_id = lpn_detail.lpn_id 
where 1=1 
and lpn.LPN_FACILITY_STATUS='30' 
and lpn.INBOUND_OUTBOUND_INDICATOR='I'; 

Answer 1

您的查询完整无缺。 如果您只想选择特定列，请在选择查询中使用列名称而不是*。

select col1,col2,col3 from lpn inner join LPN_DETAIL 
on lpn.lpn_id = lpn_detail.lpn_id 
where 1=1 
and lpn.LPN_FACILITY_STATUS='30' 
and lpn.INBOUND_OUTBOUND_INDICATOR='I'; 

Answer 2

您的查询正常，您必须编写LPN_DETAIL。*而不是*来只读取LPN_DETAIL列。

select LPN_DETAIL.* from lpn inner join LPN_DETAIL 
on lpn.lpn_id = lpn_detail.lpn_id 
where 1=1 
and lpn.LPN_FACILITY_STATUS='30' 
and lpn.INBOUND_OUTBOUND_INDICATOR='I'; 

Answer 3

如果你只需要与同一LPN多个LPN_DETAIL记录您可使用子查询：

select * from lpn inner join LPN_DETAIL 
on lpn.lpn_id = lpn_detail.lpn_id 
where 1=1 
and lpn.LPN_FACILITY_STATUS='30' 
and lpn.INBOUND_OUTBOUND_INDICATOR='I' 
and lpn_detail.lpn_id in (select lpn_id 
          from lpn_detail 
          group by lpn_id 
          having count(*)>1); 

或分析功能：

select * from(
select lpn.*,lpn_detail.*, 
     count(*) OVER (partition by lpn_detail.lpn_id) cnt 
from lpn inner join LPN_DETAIL 
on lpn.lpn_id = lpn_detail.lpn_id 
where 1=1 
and lpn.LPN_FACILITY_STATUS='30' 
and lpn.INBOUND_OUTBOUND_INDICATOR='I') 
where cnt>1;