mysql - 关系更深的 SQL 查询

Question

Table: user
Columns
- id
- username
- full_name

Table: pet
Columns
- id
- pet_name
- color_id

Table: pet_color
Columns
- id
- color

Table: results
Columns
- id
- user_id_1
- user_id_2
- user_id_3
- pet_id
- date
- some_text

这：

SELECT A.id, B.full_name, C.full_name, D.full_name, E.pet_name, A.date, A.some_text
FROM RESULTS AS A 
LEFT OUTER JOIN USER AS B ON A.USER_ID1 = B.ID
LEFT OUTER JOIN USER AS C ON A.USER_ID2 = C.ID
LEFT OUTER JOIN USER AS D ON A.USER_ID3 = D.ID
LEFT OUTER JOIN PET AS E ON A.PET_ID = E.ID

除了“pet_color.color”之外，几乎所有我想要的东西都会给我，但我不知道我应该在查询中添加什么来获得它。

Answer 1

SELECT A.id, B.full_name, C.full_name, D.full_name, E.pet_name, A.date, A.some_text, pc.color
FROM RESULTS AS A 
LEFT OUTER JOIN USER AS B ON A.USER_ID1 = B.ID
LEFT OUTER JOIN USER AS C ON A.USER_ID2 = C.ID
LEFT OUTER JOIN USER AS D ON A.USER_ID3 = D.ID
LEFT OUTER JOIN PET AS E ON A.PET_ID = E.ID
LEFT OUTER JOIN PET_COLOR PC on E.color_id = pc.id

Answer 2

SELECT A.id, B.full_name, C.full_name, D.full_name, E.pet_name, A.date, A.some_text, PC.color
FROM RESULTS AS A 
LEFT OUTER JOIN USER AS B ON A.USER_ID1 = B.ID
LEFT OUTER JOIN USER AS C ON A.USER_ID2 = C.ID
LEFT OUTER JOIN USER AS D ON A.USER_ID3 = D.ID
LEFT OUTER JOIN PET AS E ON A.PET_ID = E.ID
LEFT OUTER JOIN PET_COLOR PC ON E.COLOR_ID = PC.ID

Answer 3

没试过，但这应该可以

SELECT A.id, B.full_name, C.full_name, D.full_name, E.pet_name, A.date, A.some_text
FROM RESULTS AS A 
LEFT OUTER JOIN USER AS B ON A.USER_ID1 = B.ID
LEFT OUTER JOIN USER AS C ON A.USER_ID2 = C.ID
LEFT OUTER JOIN USER AS D ON A.USER_ID3 = D.ID
LEFT OUTER JOIN PET AS E ON A.PET_ID = E.ID
INNER JOIN PET_COLOR PC ON PC.ID = E.COLOR_ID