如何在MySQL中合並具有null的表

Question

假設我有桌子

產品

model   speed  type
1001    1      pc
1002    2      pc
1003    1      pc
2001    null   laptop
2002    null   laptop

筆記本電腦

model   speed  screen
2001    1      12
2002    2      13

我要桌子

model   speed  screen type
1001    1      null   pc
1002    2      null   pc
1003    1      null   pc
2001    1      12     laptop
2002    2      13     laptop

我的嘗試

SELECT
    product.model
FROM Laptop LEFT JOIN product
ON (product.model = laptop.model)
UNION
SELECT
    product.model
FROM Laptop RIGHT JOIN product
ON (product.model = laptop.model)

我會收到“速度不明確”的錯誤。 怎么修？

Answer 1

試試這個查詢

SELECT
    product.model, laptop.speed
FROM Laptop LEFT JOIN product
ON (product.model = laptop.model)
UNION
SELECT
    product.model, product.speed
FROM Laptop RIGHT JOIN product
ON (product.model = laptop.model)