Question

I have three tables with these fields:

product_views: ProductMasterID, Date

product_clicks: ProductMasterID, Date

product_master: ProductMasterID, Category

Anytime someone views a product on my site, it adds a row to product_views.
Anytime someone clicks on a product on my site, it adds a row to product_clicks

I am trying to write a SQL query (in MySQL/PHP) that will show me the popularity of products. Popularity is how many times it was viewed and clicked added together. I want to be able to also choose a date range, and within a certain category.

I can make it work without the date/category constrictions. I am now trying to add in the date range. This is what I have so far, for popularity of the last week:

SELECT *, COUNT(*) AS Popularity FROM 

    (SELECT product_views.ProductMasterID, product_views.Date 
         FROM product_views 
         WHERE product_views.Date BETWEEN '".date('Y-m-d',strtotime('now'))."' 
            AND '".date('Y-m-d',strtotime('-7days'))."'"."

UNION ALL 

    SELECT product_clicks.ProductMasterID,product_clicks.Date 
        FROM product_clicks 
        WHERE product_clicks.Date BETWEEN '".date('Y-m-d',strtotime('now'))."' 
           AND '".date('Y-m-d',strtotime('-7days'))."'".") a 

GROUP BY ProductMasterID ORDER BY Popularity DESC LIMIT 100"

Except that it doesnt work, it produces no results. However, if I delete either one of the WHERE clauses, then it does work for some reason, but I need both of them. So my questions are:

1. How to make it work with both WHERE clauses
2. How to do the category part e.g. selecting only products which have a category of ‘Food’. I think I would have to do a join somewhere with the product_master table, but looks tricky.

Any help would be greatly appreciated.

Thanks

Answer 1

If you want to use a JOIN, here is a solution:

• SQLFIDDLE DEMO

Query:

SELECT M.PMID, M.CATEGORY, 
(COALESCE(V.VCNT,0) +
COALESCE(C.CCNT,0)) AS TOTAL_COUNT
FROM Master M
LEFT JOIN (SELECT PMID, COUNT(*) AS VCNT
           FROM VIEWS
           WHERE DATE between 
           DATE_ADD(NOW(), INTERVAL - 7 DAY)
           and now()
           GROUP BY PMID) V
ON V.PMID = M.PMID
LEFT JOIN (SELECT PMID, COUNT(*) AS CCNT
           FROM CLICKS
           WHERE DATE between 
           DATE_ADD(NOW(), INTERVAL - 7 DAY)
           and now()
           GROUP BY PMID) C
ON C.PMID = M.PMID
GROUP BY M.PMID
;

Results:

| PMID | CATEGORY | TOTAL_COUNT |
---------------------------------
|    1 |    Shoes |           6 |
|    2 |    Books |           4 |
|    3 |     Food |           3 |

---

Using the UNION and just for the SQL part:

SELECT ID, COUNT(*) AS Popularity FROM 
(
    (SELECT product_views.ProductMasterID AS ID, count(*) 
         FROM product_views 
         WHERE product_views.Date BETWEEN '".date('Y-m-d',strtotime('now'))."' 
            AND '".date('Y-m-d',strtotime('-7days'))."'"."
         GROUP BY product_views.ProductMasterID)

UNION ALL 

    (SELECT product_clicks.ProductMasterID AS ID, COUNT(*)
        FROM product_clicks 
        WHERE product_clicks.Date BETWEEN '".date('Y-m-d',strtotime('now'))."' 
           AND '".date('Y-m-d',strtotime('-7days'))."'".") a
     GROUP BY product_clicks.ProductMasterID)

GROUP BY ProductMasterID 
ORDER BY Popularity DESC LIMIT 100"

How about this?

SELECT M.PMID, M.CATEGORY, COUNT(V.PMID), COUNT(C.PMID)
FROM MASTER M
LEFT JOIN VIEWS V
ON V.PMID = M.PMID
LEFT JOIN CLICKS C
ON C.PMID = M.PMID
WHERE V.DATE BETWEEN NOW() AND NOW() INTERVAL - 7 DAY
AND C.DATE BETWEEN NOW() AND NOW() INTERVAL 7 DAY
GROUP BY M.PMID, V.DATE, C.DATE
;