在SQL條件下需要幫助

Question

假設我有兩個表lpn和lpn_detail 如果我們在lpn表中使用lpn_id，我們只會得到一條記錄。 如果我們在lpn_detail表中使用lpn_id，我們將得到多個記錄，或者我們只能得到一條記錄。

當我們加入這兩個表時，我需要一個條件，其中Lpn_Detail的多條記錄只應該作爲結果獲取。

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

您的查詢完整無缺。 如果您只想選擇特定列，請在選擇查詢中使用列名稱而不是*。

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

您的查詢正常，您必須編寫LPN_DETAIL。*而不是*來只讀取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

如果你只需要與同一LPN多個LPN_DETAIL記錄您可使用子查詢：

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;