Question

I’m having trouble getting a query to work where data is pulled from two tables, with a 3rd table in the middle. Let me show you what I mean.

*Table companies*
id int PK
name text 

*Table projects*
id int PK
company_id int FK
project_name text

*Table hours_worked*
id int pk
user_id int FK
project_id int FK
hours float
date_worked datetime

*Table users*
id int PK
user_name text

Basically, what I need is a query that pulls the total amount of hours worked per company based on a user ID.

Note that the table_hours worked can have multiple submissions per day per project. For example, a few rows might look like

id  project_id user_id  hours  date_worked
 1       1        1       2     20-08-2012
 2       1        1       1.5   20-08-2012
 3       2        1       3     21-08-2012
 4       2        2       12    22-08-2012

My desired result would be a query that returns something like this:

company_name     total_hours
 Bobs Kitchens       25
 Mikes Bikes         67

Which returns the total number of hours worked per company (not project) for say, a user with the user ID of 1.

Here is the following query I’ve tried with no avail:

        SELECT DISTINCT companies.name as company_name,
        companies.id as company_id,
        (
          SELECT SUM(hours_worked.hours) FROM hours_worked
          WHERE projects.id = hours_worked.project_id
          AND projects.company_id = company_id
        ) as total_hours
        FROM hoursworked, companies, projects
        WHERE projects.company_id = company_id
        AND projects.company_id = projects.company_id
        AND hours_worked.user_id = 1
        GROUP BY companies.id

This is giving me an odd result where a really weird number appears to be displaying for every total_hours field. 75 is not the correct total hours for any company!

company_name   total_hours
Mikes Kitchen      75
Charlies Bikes     75
 .....             75

Any help would be greatly appreciated!

Answer 1

I was such a fool..it was actually a lot easier than I expected. Hurray for over thinking.

The query I’ve used is:

SELECT SUM(hours_worked.hours) as 'total_hours',
                companies.name
                FROM companies, hours_worked, projects
                WHERE companies.id = projects.company_id
                      AND hours_worked.project_id = projects.id
                      AND hours_worked.uid = 1
                      GROUP BY companies.id ORDER BY companies.name DESC