[英]MYSQL SELECT To fetch rows from two tables with or without a foreign key
[英]how to select distinct rows from two tables linked with foreign key
我想显示数据库中的图像。我有两个表gallery_photos
我想显示任何带有category_name的photos_filename。 photo_category是category_id的外键
我写的mysql查询
SELECT distinct a.category_name
,b.photo_filename
FROM gallery_category a
inner join gallery_photos b on (a.category_id=b.photo_category)
请帮助我做到这一点...
我想选择完全像这样
albums/1456226111.jpg interior
albums/1456226239.jpg graphics
albums/1456226339.jpg random
albums/1456226478.jpg goods
您可以按分组方式进行分组
SELECT a.category_name,b.photo_filename
FROM gallery_category a JOIN gallery_photos b
ON a.category_id=b.photo_category
GROUP BY a.category_name
使用“左联接”将所有行保留在左表中。
SELECT
b.photo_filename,
a.category_name
FROM
gallery_category a LEFT join gallery_photos b ON (a.category_id=b.photo_category)
看一下这个!
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