Effectively Firing a multiple query - php

Question

I was practicing drawing graphs on various statistics for the purpose of data analysis. But I am not able to figure out an efficient way to fire multiple mysql query at the back-end.
I am trying to draw Period Vs No of Visitors graph.
Please Note: Period here refers to week,month,3 months,6 months,1 year,2 years.
Period will be selected by the user from the select box.
For example: When User selects 3 week, I need to construct No of Visitors per 3 week graph.
My DataBase Contains Two Column: For each of the site hit, it records:
(1) timestamp and
(2)user ID.
If I fire query multiple times for each select option, then performance would be quite poor.So, How to do it efficiently?
UPD:
When User Select stats per 3 month:
Then I am firing mysql query as:
Select count(*) From stats_tab WHERE timestamp BETWEEN JAN AND MAR;
Select count(*) From stats_tab WHERE timestamp BETWEEN APR AND JUN;
Select count(*) From stats_tab WHERE timestamp BETWEEN JUL AND SEP;
............
Each count returned from each of the query will be the y-axis value for my graph
When User Select stats per year:
Then I am firing mysql query as:
Select count(*) From stats_tab WHERE timestamp BETWEEN 2009 AND 2010;
Select count(*) From stats_tab WHERE timestamp BETWEEN 2010 AND 2011;
Select count(*) From stats_tab WHERE timestamp BETWEEN 2011 AND 2012;
............

Answer 1

Don't hit database with multiple queries. Get all your values with one query appropriately applying GROUP BY and WHERE
SELECT YEAR(timestamp) year, COUNT(*) total
FROM stats_tab
WHERE timestamp BETWEEN NOW() - INTERVAL 3 YEAR AND NOW()
GROUP BY YEAR(timestamp);
SELECT MONTH(timestamp) month, COUNT(*) total
FROM stats_tab
WHERE timestamp BETWEEN NOW() - INTERVAL 6 MONTH AND NOW()
GROUP BY MONTH(timestamp);
SELECT DAY(timestamp) day, COUNT(*) total
FROM stats_tab
WHERE timestamp BETWEEN NOW() - INTERVAL 7 DAY AND NOW()
GROUP BY DAY(timestamp);
Sample output:
| YEAR | TOTAL |
----------------
| 2011 | 2 |
| 2012 | 1 |
| 2013 | 9 |
| MONTH | TOTAL |
-----------------
| 2 | 1 |
| 3 | 2 |
| 5 | 1 |
| DAY | TOTAL |
---------------
| 20 | 1 |
| 21 | 1 |
| 22 | 1 |
Here is SQLFiddle demo