Join 3 mySQL tables in one query

Question

I've spent last hours trying to find out how to generate an appropiate MySQL query to access my data. This is my sql table structure:

CREATE TABLE IF NOT EXISTS `record` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `client` int(11) NOT NULL,
  `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
)

CREATE TABLE IF NOT EXISTS `clip` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `record` int(11) NOT NULL,
  `data` int(11) NOT NULL,
)

CREATE TABLE IF NOT EXISTS `data` (
  `clip` int(11) NOT NULL,
  `name` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
  `value` text COLLATE utf8_unicode_ci NOT NULL,
)

I have minimized tables as much as possible. record table contains client data, then clip is used to join this client with some client parameters that are stored in data . Each client may have as much record 's as he wants and each record is composed by an undetermined number of *clip*s. Then, each clip references to some data values.

Ok, the query I'm looking for is one that given a sheet , a data *name* and a value it gets the last ( date ) *client*s that accomplishes the condition name =*given_name* AND value =*given_value*. It is, I'm looking for the clients that accomplishes that condition in the LAST record stored in the database.

I've arrived to this sentence:

SELECT client
FROM clip, record 
WHERE clip.id IN (SELECT clip FROM `data` WHERE name='level' AND value='2')

But it returns all clients, not only the last ones and all my tests including date have been unsuccessful.

EDIT : After some try-and-error and thanks to the ideas you gave me, I've arrived to a query that seems to work, but it is really complex and I'm quite sure you can help me to simplify:

SELECT * FROM clip, data
WHERE data.clip=clip.id 
 AND record IN (SELECT id
  FROM record a
  WHERE date = (
    SELECT MAX(date)
    FROM record b
    WHERE a.client = b.client
    )
 )
 AND data.name='NAME_HERE' AND data.value='VALUE_HERE'

Well, that's not exactly what I want, I need the client ID, but it gives me the last record for this client that is enough for me.

Answer 1

If I have understood your quesiton correctly then see if this works for you:

SELECT client
FROM record, clip, data
WHERE name = "given_name" AND value = "given_value"
AND data.clip = clip.id
AND clip.record = record.id
ORDER BY date DESC
LIMIT 0,1

Updated query based on your comments:

SELECT client, MAX(date)
FROM record, clip, data
WHERE name = "given_name" AND value = "given_value"
AND data.clip = clip.id
AND clip.record = record.id
GROUP BY client

It was helpful that you have posted some data and the output required from it. I have updated the query below:

SELECT record.client
FROM clip JOIN data ON (data.clip = clip.id)
JOIN record ON (clip.record = record.id)
JOIN (
   SELECT client, MAX(date) as date
   FROM record
   GROUP BY client
) AS r ON (r.client = record.client AND r.date = record.date)
WHERE name = "given_name" AND value = "given_value"

Answer 2

 SELECT data.name,data.value,record.client FROM data
 JOIN clip on clip.id = data.clip
 JOIN record ON record.id = clip.record WHERE data.name = 'name' AND data.value = 'value' ORDER BY record.date DESC LIMIT 0,1

Answer 3

This is the solution I've found, perhaps it could be optimized, but this needs other question:

SELECT * FROM clip, data
WHERE data.clip=clip.id 
 AND record IN (SELECT id
  FROM record a
  WHERE date = (
    SELECT MAX(date)
    FROM record b
    WHERE a.client = b.client
    )
 )
 AND data.name='NAME_HERE' AND data.value='VALUE_HERE'