使用一个选择查询选择2个表

Question

I have 2 tables on my database. One table has categories and the other one has posts. In the category table I have a column called "active".

What I'm trying to do, is to select all posts which have category=0.

Here's the select that I got so far:

SELECT tb_posts.*, tb_categories.active 
FROM tb_posts, tb_categories 
WHERE tb_categories.active='0' 
ORDER BY datapub DESC

The above query doesn't work as it loads all posts not matter the category status. :(

Answer 1

You need a left join :

SELECT tp.*, tc.active 
FROM tb_posts tp
LEFT JOIN tb_categories tc ON tb.category_id = tc.id
WHERE tc.active='0' 
ORDER BY datapub DESC

The join is done on the category column (replace with proper column name - this was my guess) which is (probably) referencing the id in the tb_categories (again, replace the name).

For an exact query, please show your table structures.