選擇列作爲列

Question

name | value | product_id 
-------+--------+------------ 
color | red |   9 
style | modern |   9 
brand | xxx |   1 
color | blue |   4 
color | red |   1 

如何選擇產品ID，其中brand = xxx和color = red？這是id = 1的產品。

Answer 1

SELECT product_id FROM tbl WHERE "name"='color' AND "value"='red' 
INTERSECT 
SELECT product_id FROM tbl WHERE "name"='brand' AND "value"='xxx'; 

Answer 2

SELECT * 
FROM YourTable T 
WHERE name = 'color' 
AND value = 'red' 
AND EXISTS(SELECT 1 FROM YourTable 
      WHERE name = 'brand' 
      AND value = 'xxx' 
      AND product_id = T.product_id)