Question

products 
id          product_cat_id         product_type_id         title       ordering
1               42                        1                 "a"            1
2               42                        1                 "b"            2  
3               42                        2                 "c"            1
4               43                        1                 "d"            1

product_cats 
id             title               ordering
1                "n"                   1
2                "b"                   2
3                "h"                   3


product_types 
id             title               ordering
1                "b"                   1
2                "n"                   2
3                "m"                   3

我的SQL查询是：

SELECT
`products`.`title`,
`product_types`.`title`
FROM
`products`,
`product_cats`,
`product_types`
WHERE
`products`.product_cat_id=42
ORDER BY `product_types`.`ordering`,`products`.`ordering` ASC

但我的SQL查询会返回所有甚至没有product_cat_id等于42的标题。我尝试使用group_by但仍然没有成功。

我正在寻找：

product_title         product_type_title
    "a"                        "b"
    "b"                        "b"
    "c"                        "n"

Answer 1

SELECT p.title AS product_title, pt.title AS product_type_title
FROM products p
INNER JOIN product_types pt
    ON p.product_type_id = pt.id
WHERE p.product_cat_id = 42
ORDER BY pt.ordering, p.ordering

Answer 2

SELECT
    `products`.`title`,
    `product_types`.`title`
FROM
    `products`
INNER JOIN
    `product_types` ON `products`.`product_type_id` = `product_types`.`id`
WHERE
    `products`.product_cat_id=42
ORDER BY
    `product_types`.`ordering`,`products`.`ordering` ASC

SQL查询排序和使用group by

2 个答案: