我可以从一个ID =另一个查询的表中选择全部的SQL查询吗？

Question

I want to be able to filter posts based on what the designers do, I have each one in a Boolean in the designer table ie Logo: 1, Website: 0 The ID is a foreign key which is the same in both tables so I want to show posts based on the data I have in the designer table.

$sqldesigner = SELECT designerID FROM designers WHERE logo = 1;

$sqlall = SELECT * FROM post WHERE designerID = $sqldesigner;

I want to show the posts based on the designer who made the post, in this example the designer makes logos so in the designer table when he signed up he ticked a box saying logo to set the logo Boolean to 1, currently I show all posts on a page but I want to have a button to filter these posts to only show posts made by a designer who makes logos, my first query is to get all the IDs of the designers who make logos then my second one was to get all posts from those designers

Hopefully I gave enough info here and thanks in advance for the help

Answer 1

You can use the following SQL statement to fulfill your requirements:

SELECT * FROM post WHERE id IN (SELECT ID FROM designers WHERE logo = 1);

The SQL IN operator allows you to specify multiple values in a WHERE clause. The IN operator is a shorthand for multiple OR conditions. More about SQL IN Operator can be found here .

OR

SELECT p.*, d.id FROM post p,designers d WHERE p.id = d.id AND d.logo = 1;

What this does, is that it helps you to rename post as p and designers as d and then apply your where conditions based on two different tables.

BOTH the above queries can be used to solve your problem.