如何在此查询中使用 LEFT JOIN

Question

我有以下问题

SELECT
    interview_content.title `title`,
    gallery_images.img_path img
FROM
    `interview`,
    `interview_content`,
    `gallery`,
    `gallery_images`
WHERE
    `gallery_images`.`id_parrent` = `gallery`.`id`
AND
    `gallery`.`id` =  `interview`.`gallery_id`
AND
    `gallery_images`.`default` = '1'
AND
    `interview`.`id` = `interview_content`.`id_parrent`
AND
    interview_content.id_lang = '2'
ORDER BY
    interview.date DESC

我需要在 gallery、gallery_images 表上使用 LEFT JOIN（即使没有图库或默认图像也能获得 interview.title）

非常感谢

更新

---

问题在于第二个 LEFT JOIN。我无法让它们正确地协同工作。当我尝试时

SELECT
    interview_content.title `title`,
    gi.img_path img
FROM
    `interview`,
    `interview_content`
LEFT JOIN `gallery` as g ON g.`id` = `interview`.`gallery_id` 
LEFT JOIN `gallery_images` as gi ON gi.id_parrent = g.`id`
WHERE
    `interview`.`id` = `interview_content`.`id_parrent`
AND
    interview_content.id_lang = '2'
ORDER BY
    interview.date DESC

it returns //Unknown column 'interview.gallery_id' in 'on clause'

Answer 1

不要混合使用 ANSI-89 样式和 ANSI-92 样式连接。

我在 SO，here 中发现了同样的问题。

所以我的查询必须是这样的

SELECT
    ic.title `title`,
    gi.img_path img
FROM
    `interview` i
JOIN interview_content ic  on ic.id_parrent =  i.id AND ic.id_lang = '2'
LEFT JOIN `gallery` as g ON g.`id` = i.`gallery_id` 
LEFT JOIN `gallery_images` as gi ON gi.id_parrent = g.`id`
AND gi.`default` = '1'
WHERE
    i.`id` = ic.`id_parrent`
OPRDER BY
    `i`.`date` DESC

Answer 2

试试那个：

SELECT
    interview_content.title `title`,
    gallery_images.img_path img
FROM
    `interview`,
    `interview_content`,
LEFT JOIN `gallery` ON (`interview`.`gallery_id` = `gallery`.`id` AND `gallery_images`.`default` = '1'), 
LEFT JOIN `gallery_images` ON `gallery`.`id` = `gallery_images`.`id_parrent`
WHERE
    `interview`.`id` = `interview_content`.`id_parrent`
AND
    interview_content.id_lang = '2'
ORDER BY
    interview.date DESC;

Answer 3

你知道你需要做什么。 Google 是你的朋友吗？

http://en.wikipedia.org/wiki/Join_%28SQL%29#Left_outer_join