php - How to check if a row exists when there are two tables involved?

Question

I have two MySQL tables something like this:

tool_owners:

tool_owners_id | user_id | ...

tools:

tools_id | tool_owners_id | tool_name | ...

I have the user_id and tool name. I need to check to see if the user owns a specific tool. The challenge is that these bits of information (the user_id and tool_name) are in separate tables, where the rows are linked by tool_owners_id.

In case anyone is wondering, I can't change the structure of the tables.

Is what I'm asking possible? The only way I know how to do this is to make a first query getting the tool_owners_id from the tool_owners table, then a second query doing COUNT(*) where the tool_owners_id = xxx AND tool_name = xxxx from the tools table.

Thanks for your help!

Answer 1

use a join

SELECT * 
FROM table1 
LEFT JOIN table2 
    ON table1.tool_owners_id=table2.tool_owners_id 
WHERE table1.user_id=1 
AND table2.tool_name='hammer'