Question

假设我有两个表lpn和lpn_detail 如果我们在lpn表中使用lpn_id，我们将只获得一条记录。如果我们在lpn_detail表中使用lpn_id，我们将获得多条记录，或者我们可能只获得一条记录。

当我们加入这两个表时，我需要一个条件，Lpn_Detail的多个记录只能作为结果获取。

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

您的查询没问题。如果您只想选择特定列，请在选择查询中使用列名而不是*。

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

您的查询没问题，您必须编写LPN_DETAIL。*而不是*才能获取LPN_DETAIL列。你可以把它写成：

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

如果您只需要具有多个LPN_DETAIL的记录用于相同的LPN，则可以使用任一子查询：

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);

或分析函数：

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;

需要SQL条件的帮助

3 个答案: