mysql - 如何在 mySQL 中将表与 null 合并

Question

假设我有 table

产品

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

笔记本电脑

model   speed  screen
2001    1      12
2002    2      13

我要 table

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

我的尝试

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)

我会收到“速度不明确”的错误。如何修复？

Answer 1

试试这个查询

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)