MySQL Query Select from table count total and used, calculate remaining

Question

I have two tables :

-- **phones**

CREATE TABLE IF NOT EXISTS `phones` (
`phone_id` int(11) NOT NULL AUTO_INCREMENT,
`phone_type_id` int(11) NOT NULL,
`phone_mac` varchar(255) NOT NULL,
`office_id` int(11) DEFAULT NULL,
`did_id` int(11) DEFAULT NULL,
`virtual_extension_id` int(11) DEFAULT NULL,
PRIMARY KEY (`phone_id`),
UNIQUE KEY `phone_mac` (`phone_mac`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=67 ;

INSERT INTO `phones` (`phone_id`, `phone_type_id`, `phone_mac`, `office_id`, `did_id`, `virtual_extension_id`) VALUES
(1, 1, '0004f22ccccc', 5, NULL, NULL),
(63, 1, '0004f22bbbbb', 9, 33, NULL),
(64, 20, '0004f22aaaaa', 6, NULL, 6600),
(65, 2, '000033434333', 9, NULL, NULL),
(66, 20, '21232da32434', 6, NULL, NULL);

--  **phone_types**

CREATE TABLE IF NOT EXISTS `phone_types` (
  `phone_type_id` int(11) NOT NULL AUTO_INCREMENT,
  `phone_type_manufacturer` varchar(255) NOT NULL,
  `phone_type_model` varchar(255) NOT NULL,
  PRIMARY KEY (`phone_type_id`),
  UNIQUE KEY `phone_type_model` (`phone_type_model`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;

INSERT INTO `phone_types` (`phone_type_id`, `phone_type_manufacturer`, `phone_type_model`) VALUES
(1, 'Polycom', 'SoundPoint IP 550'),
(2, 'Polycom', 'SoundPoint IP 450'),
(3, 'Polycom', 'SoundPoint IP 335'),
(4, 'Polycom', 'SoundPoint IP 560'),
(5, 'Polycom', 'SoundPoint IP 670'),
(6, 'Polycom', 'SoundStation IP 5000'),
(7, 'Polycom', 'SoundStation IP 6000'),
(8, 'Yealink', 'W52P'),
(20, 'Aastra', '6757i CT');

I am able to select all the phones from the phone_types table and then get a total count of how many of those phones are within the Phones table, phone_type_id column.

I need to count how many of those phones have a value (NOT NULL) in the Phones table, in did_id or virtual_extension_id. This is where I'm hung up.

Here's what I have so far. Note that I currently am using the same count total and used as I can't figure out the used count. Any help is greatly appreciated. Thanks in advance.

SELECT 
phone_types.phone_type_id AS phone_type_id, 
phone_type_manufacturer AS phone_type_manufacturer, 
phone_type_model AS phone_type_model, 
COUNT( phones.phone_type_id ) AS total_count, 
COUNT( phones.phone_type_id ) AS used_count
FROM  phone_types 
LEFT JOIN phones ON phones.phone_type_id = phone_types.phone_type_id
GROUP BY phone_types.phone_type_id

Sample Output:

    1 | Polycom | SoundPoint IP 550    | 2 | 2
    2 | Polycom | SoundPoint IP 450    | 0 | 0
    3 | Polycom | SoundPoint IP 335    | 0 | 0
    4 | Polycom | SoundPoint IP 560    | 0 | 0
    5 | Polycom | SoundPoint IP 670    | 0 | 0
    6 | Polycom | SoundStation IP 5000 | 0 | 0
    7 | Polycom | SoundStation IP 6000 | 0 | 0
    8 | Yealink | W52P                 | 0 | 0
   20 | Aastra  | 6757i CT             | 1 | 1

Edited: added create and insert statements.

Edited: Seem to be making progress.

SELECT phone_types.phone_type_manufacturer, phone_types.phone_type_model, COUNT( phones.phone_type_id ) AS Total, COUNT( phones.did_id OR virtual_extension_id ) AS Used FROM phones INNER JOIN phone_types ON phones.phone_type_id = phone_types.phone_type_id GROUP BY phones.phone_type_id

which gives me the following output: manufacturer model total Used Polycom Soundpoint IP 550 2 1 Polycom SoundPoint IP 450 1 0 Aastra 6757i CT 2 1

This is correct but I need to show the other phones also that have a NULL value in both did_id and virtual_extension_id?

Answer 1

I guess you're after something like this... although I don't really understand how your data set tallies with your result set ?!?!

SELECT t.phone_type_id
     , t.phone_type_manufacturer
     , t.phone_type_model
     , COUNT(COALESCE(did_id,virtual_extension_id)) x
  FROM phone_types t 
  LEFT 
  JOIN phones p 
    ON p.phone_type_id = t.phone_type_id
 GROUP 
    BY t.phone_type_id;