MySql subquerying to pull data from another table - mysql

Question

I am currently using phpMyAdmin supporting MySql 5.0.
I have the following two tables:
Master Facebook Insights
------------------------
Client ID Client Name Date Top Likes By Gender
--------- ----------- ------ --------------------
1 Client1 2012-01-01
1 Client1 2012-02-01
2 Client2 2012-01-01
2 Client2 2012-02-01
...etc. (the dates are always the beginning of each month for however many months
& clients exist)
Likes By Demographic
----------------
Date Demographic1 Demographic2 Demographic3 Client
------ ------------ ------------ ------------ ------
0000-00-00 M.35-44 M.45-54 M.25-34 1
2012-01-01 53 44 28 1
2012-01-02 53 46 29 1
...etc.
0000-00-00 M.18-24 M.35-44 M.25-34 1
2012-02-01 374 221 194 1
2012-02-02 374 222 195 1
...etc.
0000-00-00 F.35-44 F.25-34 M.35-44 2
2012-01-01 194 182 83 2
2012-01-02 194 182 83 2
...etc.
0000-00-00 F.35-44 F.25-34 M.35-44 2
2012-02-01 196 180 83 2
2012-02-02 197 180 83 2
...etc.
For the Likes By Demographic table:
All days of each month are listed per client; when a new month begins,
there is a new set of demographics that may or may NOT be listed exactly the same
as the previous month. This is because the data was imported from a CSV that put the demographics in order of highest 'likes,' so this usually changes month to month. This is also the reason that the individual demographics are not the column headers (because they are inconsistent).
My problem is the following:
I wish to list the top 3 demographics per month for each client in the 'Top Likes By Gender' column of the first table, like so:
Client ID Client Name Date Top Likes By Gender
--------- ----------- ------ --------------------
1 Client1 2012-01-01 M.35-44, M.45-54, M.25-34
1 Client1 2012-02-01 M.18-24, M.35-44, M.25-34
2 Client2 2012-01-01 F.35-44, F.25-34, M.35-44
2 Client2 2012-02-01 F.35-44, F.25-34, M.35-44
The use of subqueries is confusing me. The following is the (incorrect) code I have been trying to fix. The problem is that is just extracts the first three demographics for the first client (M.35-44, M.45-54, M.25-34) and repeats them down the entire column for all clients and dates.
Am I on the right track, or is there a much simpler/more correct way to do this?
UPDATE `Master Facebook Insights`
SET `Top Likes By Gender` =
(select * from
(SELECT DISTINCT CONCAT(`Demographic1`,', ',`Demographic2`,', ',`Demographic3`)
FROM `Likes By Demographic` t1
JOIN `Master Facebook Insights` t2
ON t1.`Client` = t2.`Client ID`
WHERE t1.`Date` = '0000-00-00'
AND t2.`Date` =
(
SELECT MIN(`Date`)
FROM `Likes By Demographic`
WHERE `Date` > '0000-00-00'
AND `Client` = t2.`Client ID`
GROUP BY `Date`
ORDER BY `Date` ASC
LIMIT 1
)
)inner1 limit 1)
Thank you so much for the help!

Answer 1

Just using the original Likes_By_Demographic table, you can do:
select
client_id,
date,
concat(demo1,', ',demo2,', ',demo3) `top_likes`
from likes_by_demographic
group by client_id, date
order by client_id, date;
...which will yield (pseudo-data):
| CLIENT_ID | DATE | TOP_LIKES |
-----------------------------------------------------------------------
| 1 | January, 01 2012 00:00:00-0800 | M.35-44, M.25-34, 195 |
| 1 | February, 01 2012 00:00:00-0800 | M.25-34, M.35-44, 195 |
| 1 | March, 01 2012 00:00:00-0800 | M.25-34, 195, 169 |
| 2 | January, 01 2012 00:00:00-0800 | F.45-54, 210, 195 |
| 2 | February, 01 2012 00:00:00-0800 | F.45-54, 210, 75 |