MySQL - Query Multiple values in a single column - php

Question

I am currently working on a site utilizing the WP-Property plugin for Wordpress.
Basically I am attempting to display a counter next to a text search link for a particular price range.
Below is the query I am running which does the price range count perfectly fine.
$apartprice1 = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->postmeta WHERE meta_value BETWEEN 50000 AND 74999");
if (0 < $apartprice1) $apartprice1 = number_format($apartprice1);
I would however like to extend on this to display only "Apartments" which are within this particular price range.
Now bear in mind that within the meta_value column the property type values (apartments, houses, freeholds) are also stored.
Any boffins about whom can demystify this for me please?
edit: Some further elaboration below:
Table name is postmeta
meta_id post_id meta_key meta_value
348 41 property_type apartment
358 41 price 698000
So I would like to be able to do a count of a particular price range which is also based on a specific property type

Answer 1

This table structure makes it somewhat difficult/inefficient to do the type of multifacet searching you're looking for. To ensure that all WHERE clauses are met, you'll need to INNER JOIN the meta table to itself. This gives you a temporary data format that's bit more suitable for your query.
SELECT m1.post_id
FROM meta m1
INNER JOIN meta m2 ON m1.post_id = m2.post_id
WHERE m1.meta_key = 'price'
AND m1.meta_value
BETWEEN 50000 AND 7000000 AND m2.meta_key = 'property_type'
AND m2.meta_value = 'apartment'
Keep in mind, for every additional facet you add, you'll need to do an additional INNER JOIN. Also, if you don't have one already, I'd recommend an index on the post_id column.
To get the count, just change what's in the SELECT clause.
SELECT COUNT(*)
FROM meta m1
INNER JOIN meta m2 ON m1.post_id = m2.post_id
WHERE m1.meta_key = 'price'
AND m1.meta_value
BETWEEN 50000 AND 7000000 AND m2.meta_key = 'property_type'
AND m2.meta_value = 'apartment'

Answer 2

If you are looking for displaying the count for each of the property values the partments, houses, freeholds, you should add a GROUP BY property_type
SELECT property_type, COUNT(*)
FROM $wpdb->postmeta
WHERE meta_value BETWEEN 50000 AND 74999
GROUP BY property_type
Update: You have to pivot your rows into columns in order to get the data the way you described like so:
SELECT t.property_type, COUNT(t.post_id) AS 'type count'
FROM
(
SELECT t.post_id,
MAX(CASE WHEN t.meta_key = 'property_type' THEN t.meta_value END) AS property_type,
MAX(CASE WHEN t.meta_key = 'price' THEN CAST(t.meta_value AS DECIMAL) END) AS Price
FROM postmeta t
GROUP BY t.post_id
) t
WHERE t.property_type = 'apartment'
AND t.Price BETWEEN 600000 AND 700000
GROUP BY t.property_type
Note that the meta_value field is supposed to store both a string values for property types as well as numeric values for prices so I CAST it to DECIMAL in order to select it as numeric data type so that you can perform calculation on it later on. I also used MAX as an aggregate function as a work around to pivot the rows.
Here is a demo in SQL fiddle.
This what you usually encounter in such a design model which is what they called Entity–attribute–value model. You can find a lot of useful thread about this data model under the tag eav. You can also find more useful pages about this design model in the following answer