Question

I run a query against a MySQL database to get total number of visits grouped by week.
The structure of the table is:

|ID (int) | SESSION (char) | TIMESTAMP (datetime) |

My query looks like this:
'SELECT COUNT(session), WEEKOFYEAR(timestamp)
FROM stats
GROUP BY WEEKOFYEAR(timestamp)
ORDER BY timestamp ASC';

So I get an array of week numbers eg 40,41,45 etc, along with the view count.

How can I convert this into readable date (using PHP)? It’s not practical to say, “Week number 40-something: 2000 visits”.

I’m looking for something in the form of StartDate-EndDate/Month/Year, eg. Week 5-11/12/2011, Visits: XXXX.

Any functions you might have used before? I’ve tried but with no luck.

Is my SQL query a correct way to do it? Assuming that I’m querying the db correctly for what I’m trying to accomplish, is there a way to convert a week number into a day/date span?

I’m also wondering what will happen if a week spans between two months or even two years.

Answer 1

Assumptions:

• The date you want to display is the Monday Week Date for that week
• Your main output is Week <week number>-<monday date of week>, Visits: <count>.
• You know enough PHP to be able to pull the column Phrase

The following SQL command should display for you the count of sessions per week of year, the week of year, and your desired phrase:

SELECT COUNT(session) AS VisitCount
    , WEEKOFYEAR(timestamp) AS WeekOfYear_Value
    , MAKEDATE(
        CASE 
            WHEN WEEKOFYEAR(timestamp) = 52 
                THEN YEAR(timestamp)-1 
            ELSE YEAR(timestamp) 
        END, (WEEKOFYEAR(timestamp) * 7)-4) AS DateOfWeek_Value
    , CONCAT('Week ', WEEKOFYEAR(timestamp)
        , '-', MAKEDATE(
            CASE 
                WHEN WEEKOFYEAR(timestamp) = 52 
                    THEN YEAR(timestamp)-1 
                ELSE YEAR(timestamp) 
            END, (WEEKOFYEAR(timestamp) * 7)-4) -- Monday
        , ', Visits: ' , COUNT(session), '.') AS Phrase
FROM stats
GROUP BY WEEKOFYEAR(timestamp)
ORDER BY timestamp ASC

Try it out on your existing data.

[edit : additional code changes]

To get you the Sunday output:

SELECT COUNT(session) AS VisitCount
    , WEEKOFYEAR(timestamp) AS WeekOfYear_Value
    , CONCAT('Week ', WEEKOFYEAR(timestamp)
        , '-', MAKEDATE(
            CASE 
                WHEN WEEKOFYEAR(timestamp) = 52 
                    THEN YEAR(timestamp)-1 
                ELSE YEAR(timestamp) 
            END, 
            CASE 
                WHEN WEEKOFYEAR(timestamp) = 52 
                    THEN (WEEKOFYEAR(timestamp) * 7)+3
                ELSE (WEEKOFYEAR(timestamp) * 7)+2
            END
            )
    , ', Visits: ' , COUNT(session), '.') AS Phrase
FROM stats
GROUP BY WEEKOFYEAR(timestamp)
ORDER BY timestamp ASC

Also notice that this last update includes another CASE in the makedate command, to ensure consistency between dates from the current and last year values.