分組相似的價值觀進入新的select語句

Question

我有一個表，看起來像這樣...

supplier_name status  count 
supplier_a  Unavailable 1 
supplier_a  Refunded  5 
supplier_a  Shipped  10 
supplier_z  Refunded  2 
supplier_z  Shipped  4 

我知道正是我想要的欄目，我想使用的值從第一個表返回值結構類似於以下...

supplier_name unavailable refunded shipped 
supplier_a  1    5   10 
supplier_z  0    2   4 

（注：在有特定列，應設置爲0，沒有值的情況下）

這將是可能的實現查詢？

Answer 1

我覺得這樣的事情應該工作：

SELECT Supplier_Name, 
    MAX(CASE WHEN STATUS = 'Unavailable' THEN Count ELSE 0 END) as Unavailable, 
    MAX(CASE WHEN STATUS = 'Refunded' THEN Count ELSE 0 END) as refunded, 
    MAX(CASE WHEN STATUS = 'Shipped' THEN Count ELSE 0 END) as shipped 
FROM YourTable 
GROUP BY Supplier_Name 

這裏是SQL Fiddle。

祝你好運。

Answer 2

試試這個：

SELECT 
    supplier_name, 
    SUM(COALESCE(CASE WHEN status = 'unavailable' THEN `count` END, 0)) unavailable, 
    SUM(COALESCE(CASE WHEN status = 'refunded' THEN `count` END, 0)) refunded, 
    SUM(COALESCE(CASE WHEN status = 'shipped' THEN `count` END, 0)) shipped 
FROM tbl 
GROUP BY supplier_name 

SQL FIDDLE DEMO