Question

I am having trouble working out how to return the correct row in a table given that said table is relational. The two tables are shown below.

web_quote_models table

id | model       | product_id | cpu_id | ram_id | hdd_id | os_id | opt_id 
=========================================================================
1  | 000001      | 1          | 1      | 1      | 1      | 1     | 1
2  | 000002      | 1          | 2      | 2      | 2      | 2     | 2
3  | 000003      | 1          | 3      | 3      | 3      | 3     | 3
4  | Custom      | 0          | 0      | 3      | 4      | 4     | 4

web_quote_component_cpu table

id | name
=========================================================================
1  | Intel® Core™ i3 2100 3.1GHz dual-core
2  | Intel® Core™ i5 2500 2.7GHz quad-core        
3  | Intel® Core%trade; i7 2600 3.4GHz 8mb Cache dual-core

So what I need to achieve is a query that will look inside the web_quote_models table and match the model field with a $_SESSION[‘model’] then match the web_quote_models.cpu_id field with the web_quote_component.id.

This is what I have so far; I cant be too far off I think.

("
 SELECT web_quote_component_cpu.name
 FROM web_quote_component_cpu
 LEFT JOIN web_quote_models
 ON web_quote_component_cpu.id='web_quote_models.cpu_id'
 AND web_quote_models.name='".$_SESSION['model']."'
");

A massive thank you in advance to anyone that helps.

Dan.

Answer 1

I don’t think you’re far off at all. I believe that all you need to do is stop quoting web_quote_models.cpu_id:

 SELECT web_quote_component_cpu.name
 FROM web_quote_component_cpu
 LEFT JOIN web_quote_models
 -- note lack of quotes in the following line:
 ON web_quote_component_cpu.id=web_quote_models.cpu_id
 AND web_quote_models.name='".$_SESSION['model']."'

Edit

Based on the comment, I would personally re-write the query:

 SELECT web_quote_component_cpu.name
 FROM web_quote_component_cpu WHERE ID IN
 ( SELECT ID FROM WEB_QUOTE_MODELS WHERE 
   web_quote_models.name='".$_SESSION['model']."' );

Though I would suspect that swapping that last AND with a WHERE would be sufficient:

 SELECT web_quote_component_cpu.name
 FROM web_quote_component_cpu
 LEFT JOIN web_quote_models
 -- note lack of quotes in the following line:
 ON web_quote_component_cpu.id=web_quote_models.cpu_id
 WHERE web_quote_models.name='".$_SESSION['model']."'