SQL選擇 - 轉換列中的行

Question

非常基本，但我現在卡住了。

在Informix數據庫（無支點選項），我正在尋找使用SQL下表改造，以動態方式：

 
book  | info | value 
----------------------------- 
Moby Dick | price | high 
Moby Dick | stock | few 
Hamlet  | price | low 
Hamlet  | stock | many 
Faust  | price | medium 
Faust  | stock | normal 

結果表：

 
book  | price | stock 
----------------------------- 
Moby Dick | high | few 
Hamlet  | low | many 
Faust  | medium | normal 

感謝您的幫助！

Answer 1

您可以基於CASE表達式按書集合進行聚合。嘗試這樣的事情。

SELECT book, 
MAX(CASE WHEN info = 'price' THEN value END) as price, 
MAX(CASE WHEN info = 'stock' THEN value END) as stock 
FROM table1 
GROUP BY book