mysql - 我可以使用一个语句从每一列中获取不同的行吗

Question

请看一下这个fiddle

是否可以将这四个不同的查询合并到一个语句中？

SELECT DISTINCT(name) from `product` order by name;
SELECT DISTINCT (category) from `product` order by category;
SELECT DISTINCT (price) from `product` order by price;
SELECT DISTINCT (year) from `product` order by year;

我想从每一列中获取不同的行，并以 JSON 格式返回选择框选项的结果，但我不知道如何在不使用四个独立的选择语句的情况下返回如下结果:

NAME   
A
C
D
E
G

CATEGORY
Brainteaser
Doll
Outdoor

PRICE

20
22
25
30
34

YEAR

2008
2009
2010

表: 创建表产品 (ID int，名称 varchar(1)，类别 varchar(11)，价格 int，年int) ;

INSERT INTO product
    (`ID`, `name`, `category`, `price`,`year`)
VALUES
    (1, 'A', 'Outdoor', 25,2010),
    (2, 'A', 'Doll', 34,2009),
    (3, 'C', 'Doll', 25,2008),
    (4, 'D', 'Outdoor', 20,2010),
    (5, 'E', 'Brainteaser', 22,2010),
    (6, 'E', 'Brainteaser', 22,2009),
    (7, 'G', 'Brainteaser', 30,2009),
    (8, 'G', 'Brainteaser', 30,2009)
;

Answer 1

也许你可以尝试这样的事情:

SELECT DISTINCT(name) FIELDVALUE, 'NAME' FIELDNAME from `product` 
UNION
SELECT DISTINCT (category) FIELDVALUE, 'CATEGORY' FIELDNAME from `product` 
UNION
SELECT DISTINCT (price) FIELDVALUE, 'PRICE' FIELDNAME  from `product` 
UNION
SELECT DISTINCT (year) FIELDVALUE, 'YEAR' FIELDNAME  from `product` ;

它的输出为:

FIELDVALUE      FIELDNAME
A               NAME
C               NAME
D               NAME
E               NAME
G               NAME
Outdoor         CATEGORY
Doll            CATEGORY
Brainteaser     CATEGORY
25              PRICE
34              PRICE
20              PRICE
22              PRICE
30              PRICE
2010            YEAR
2009            YEAR
2008            YEAR