ORACLE SQL查詢技巧。如何顯示一行？ SQL

Question

早安

我有這樣

例如表

此表名爲 「注意」

id------alloc_code------Note_type-------Note 
1  AA    ss   hello 
2  AA    sc   good 
3  BB    ss   something 
4  BB    sc   anything 

我想顯示

alloc_code  Note_Type  Note  Note_Type  Note 
AA    SS   hello  SC   good 
BB    SS   something SC   Anything 

如何我可以這樣編碼嗎？

Answer 1

您可以通過音符表做一個SELF JOIN和使用WHERE條款做這個篩選note_types SS和SC：

SELECT 
n1.alloc_code, 
'SS' AS Note_type, 
n1.Note, 
'SC' AS Note_type, 
n2.Note 
FROM note AS n1 
LEFT JOIN note AS n2 ON n1.alloc_code=n2.alloc_code 
WHERE n1.Note_type='ss' 
AND n2.Note_type='sc'; 

Answer 2

一種方法是有條件聚集：

select alloc_code, 
     'SS' as Note_Type, max(case when Note_Type = 'ss' then Note end) as ss_note, 
     'SC' as Note_Type, max(case when Note_Type = 'sc' then Note end) as sc_note 
from note n 
group by alloc_code;