MYSQL loop this code - mysql

Question

I want the following code to run with multiple end dates. those end dates must al be the first day of the month.
I can execute the code several times while changing the end date myself but thats to much work of i want montly data from 2001 until now. So my guess is I have to loop this?
Here is the code i'm using:
Select t4.Count, t4.Status
From(
SELECT count(l.VoerID) as Count, l.Datum, l.Status, l.LogID
FROM (
SELECT k.VoerID, k.Datum, MAX(k.LogID) AS LogID
FROM DB.LogStatus k
Where Datum > '2001-01-01'
and Datum < '2013-07-01'
GROUP BY k.VoerID
) m
JOIN DB.LogStatus l
ON l.VoerID = m.VoertuigID AND l.LogID = m.LogID
Where status in ('x',y,'z')
Group by Status
)t4
Who can help?
EDIT::::: #STEPH
When I use this peace of code (1):
SELECT VoertID,max(LogID) as MaxLogID,Datum
from DB.LogStatus
WHERE Datum >= '2001-01-01'
and Datum < '2013-07-01'
and VoerID = '50789'
GROUP BY VoerID
i get VoerID 50789 with the last LogID but not the corresponding date. hows that possible?

Answer 1

Based on your output, you need to manipulate your date to always return the first of the month.
In the SQL below, I have presented a moethod to do so that involves working out how many days past the begining of the month (relative to each date) there has been and substracting it.
SELECT date_sub(Datum,interval day(Datum)-1 day) datum, status, count(l.VoerID) as count
FROM DB.LogStatus l
INNER JOIN (SELECT VoerID,max(LogID) as MaxLogID
from DB.LogStatus
WHERE Datum >= '2001-01-01'
and Datum < '2013-07-01'
GROUP BY VoerID) maxl on l.VoerID=Maxl.VoerID and l.LogID=Maxl.MaxLogID
Where status in ('x','y','z')
and Datum >= '2001-01-01'
and Datum < '2013-07-01'
GROUP BY date_sub(Datum,interval day(Datum)-1 day),status
Breaking down your original code:
Return for a given VoerID, return the FIRST Date and MAX LogID
SELECT k.VoerID, k.Datum, MAX(k.LogID) AS LogID
FROM DB.LogStatus k
Where Datum > '2001-01-01'
and Datum < '2013-07-01'
GROUP BY k.VoerID
Get all items from the log where the status is in a range and where the LogIDs match and the VoerID in the table matches the VoertuigID from the derived table (not actually present in code). Group by log status and get FIRST Datum, FIRST LogID and the COUNT
SELECT count(l.VoerID) as Count, l.Datum, l.Status, l.LogID
FROM ( step1 ) m
JOIN DB.LogStatus l
ON l.VoerID = m.VoertuigID AND l.LogID = m.LogID
Where status in ('x',y,'z')
Group by Status
Return Count and Status columns from 2
The revised code does:
Identifies last LogID for each VoerID within certain dates
SELECT VoerID,max(LogID) as MaxLogID
from DB.LogStatus
WHERE Datum >= '2001-01-01'
and Datum < '2013-07-01'
GROUP BY VoerID
Restricts log by these max LogIDs, then filters on relevant statuses, and then counts the number of rows per status per first of month
SELECT date_sub(Datum,interval day(Datum)-1 day) datum, status, count(l.VoerID) as count
FROM DB.LogStatus l
INNER JOIN ( m ) maxl on l.VoerID=Maxl.VoerID and l.LogID=Maxl.MaxLogID
Where status in ('x','y','z')
and Datum >= '2001-01-01'
and Datum < '2013-07-01'
GROUP BY date_sub(Datum,interval day(Datum)-1 day),status