Stuck on dates using interval - mysql

A little stuck, the end user is allowed to pick a year/month and then collect the data going back 5 months. I'm good with setting the initial date off a timestamp (yyyy-mm-dd hh:mm:ss) column but can I use last_day in conjunction with interval. So if the end user picks May 2013 they can collect all the data from May 31, 2013 through January 1, 2013.
Ex. set #d2:=concat('2013-05','-01');
set #d1:=#d2 - last_day(interval 5 month);
select #d1,#d2;
Any help/guidance is much appreciated.

The function LAST_DAY takes a date as an argument, not an interval.
It would appear that the code you want is:
set #d1 := LAST_DAY(#d2 - INTERVAL 5 MONTH)

Related

Date Intervals Doesn't work

I am trying to get data by week, month and year.
I store date YYYY-MM-DD HH:MM:SS.
What I am doing is below;
Fetch one week old data;
query + AND WEEK(date) = WEEK(CURDATE())
Fetch a month old data;
query + AND MONTH(date) = MONTH(CURDATE())
The thing is I couldnt be able to get the data correct. For instance when I want to get week old data, I am gettin a year old one too.
Is there any other query that I could use? I have tried DATE(NOW()) - INTERVAL 30 DAY. It works but very slow.
Thanks!
I believe that the problem is that the WEEK function returns the week of the year. So, Jan 1st 2017 might be week 1 (also might be week 53 of the previous year depending on the day of the week and how MySQL handles it). But then, Jan 1st of 2016 is also week 1 - just for a different year.
Trying changing it to:
query + AND WEEK(date) = WEEK(CURDATE()) AND YEAR(date) = YEAR(CURDATE())
Also, if you're storing this as a string then definitely change it to a DATETIME
WHERE ...
AND date >= CURDATE() - INTERVAL 7 DAY
AND date < CURDATE()
Gives you the 7 days ending with yesterday. Use other techniques to get a particular month or week.
This technique is also much faster for large tables with a suitable index. Hiding date inside a function, such as WEEK() prevents the use of an index.

Rewritten mySQL Statement

SELECT DATE(STR_TO_DATE(CONCAT(CONCAT(YEAR('$uDate1'), week), ' Monday'), '%X%V %W') +
INTERVAL (7 - DAYOFWEEK(STR_TO_DATE(CONCAT(CONCAT(YEAR('$uDate1'), week), ' Monday'),
'%X%V %W'))) DAY)
as week_end_date
What this statement does is take the date I give it ($uDate1) and give me the week end date (Saturday) of that week. This works well and I am happy with it, kinda.
I was wondering if there were some things I missed that would either make this more efficient or even if I missed some shortcuts to this.
Any suggestions for me?
week >= WEEK('$uDate1') AND week <= WEEK('$uDate2')
This is in my WHERE clause. So basically if I use this...
DATE('$uDate1', INTERVAL 7 - DAYOFWEEK('$uDate1') DAY)
...then it returns the same day for all records. I need it to be able to go over a span of a few weeks.
I have a column in my database named 'week'. It simply stores an INT that corresponds to the week of the year. (ex. 21 for this week)
I then have two date picker boxes. The output gets the week end date based of each week that is BETWEEN and INCLUDES the days chosen.
5/10/2016 & 5/26/2016 outputs 5/14/2016, 5/21/2016, 5/28/2016
What gets exported to CSV file looks something like this..
WEEK END, LAST NAME, FIRST NAME, ...
5/10/2016, Smith, John, ...
5/26/2016, Jones, James, ...
It outputs anyone who had hours during the week, with the week end date.
SIDE NOTE: I do appreciate the comments and help. I don't want anyone to stress over this though! Just curious if better way. :)
I am not sure why your current SQL is so complicated.
You say it is just to take a date and give me the week end date (Saturday) of that week .
How you are doing this at the moment is:-
Yours is taking the year
Adding the week of the year (I assume - should be WEEK('$uDate1') I think)
Adding on the day as a string (so for example for today it would be 2016 21 Monday )
Changing that string back to a date a datetime value
Converting that datetime value back to a date.
Then taking the year again
Adding the week of the year again
Getting the day of the week of the resulting string. As you have concatenated Monday on to the date then the day of the week will always be 2.
Taking that resulting day of the week and subtracting it from 7. As the day of the week will always be 2 this will always result in 5
Adding on the day as a string (so for example for today it would be 2016 21 Monday ).
This value is then added on to the previously calculated date, taking the Monday date and adding 5 days.
My suggestion was to just use:-
DATE_ADD($uDate1, INTERVAL 7 - DAYOFWEEK($uDate1) DAY)
which is far simpler, and appears to cover your requirements.
EDIT
Looking at your edit you want a list of all the Saturdays for weeks all or partially between 2 passed dates.
If so I think the following will do it and hopefully be more efficient as there is no need to translate dates to and from string. Note it relies on your week table to add to the date, hence only copes with date ranges of up to that many weeks.
SELECT DATE_ADD(DATE_ADD('$uDate1', INTERVAL 7 - DAYOFWEEK('$uDate1') DAY), INTERVAL `week` WEEK) AS aDate
FROM `week`
HAVING aDate BETWEEN '$uDate1' AND DATE_ADD('$uDate2', INTERVAL 7 - DAYOFWEEK('$uDate2') DAY)
ORDER BY aDate
As I mentioned in comment you should move this transformation from mysql query to php code.
I see no reason to do this calculation on mysql side.
http://ideone.com/48zLvF
$week_day = intval(date('w',$uDate1));
if ($week_day<6) {
$end_of_week = $uDate1+(86400*(6-$week_day));
} else {
$end_of_week = $uDate1;
}

Selecting rows with a set date+a month offset with MySQL

I have a MySQL database with one table that contains a data field and a "period" field, in months - int.
The idea is that the date indicates a due date to begin a project inside my company. And the "period" the period of time it is suppose to take to finish it, in months.
I need to select rows that will impact a given year. So if I am generating a report for 2014, I need to select the rows such: date+period is inside 2014.
It will be easy to do it inside the program, but I am looking for a way to do it in the query - if possible.
So basically I just need a way to sum dates and ints in a query, where the int is the number of months.
Any thoughts?
It's easy to do date arithmetic in MySQL and other RDMS systems. You need all the records in which the start date is not after the year in question OR the end date is not before the year in question. That is this expression:
NOT(YEAR(start_date) > 2014 OR YEAR(start_date + INTERVAL period MONTH) < 2014)
This logically reduces to
YEAR(start_date) <= 2014 AND YEAR(start_date + INTERVAL period MONTH) >= 2014
So this query will do it.
SELECT whatever, whatever
FROM project
WHERE YEAR(start_date) <= 2014
AND YEAR(start_date + INTERVAL period MONTH) >= 2014
AND (whatever other selection criteria you have)
This will give all projects that were active during 2014, including those that started before 2014 and those that will still be in progress at the end of that year.

Fetch mysql data of timstamp depending on time given

I have a column with timestamp, contain example value "2014-04-16 18:00:00","2014-04-17 18:00:00"....
Now, if I will call a page before "2014-04-17 12:00:00" I need this value-"2014-04-16 18:00:00"
And if I call my page after "2014-04-17 12:00:00" I need this value "2014-04-17 18:00:00".
I think my question is very complicated to understand, having complications in date & times, please check date & time properly.
I want to fetch this data from DB in mysql, The page I was saying is that where I'm going to add your mysql query.
Thanx in advance
Generalising what your asking for a bit the following will return dates from the previous day if it's before noon and dates from today if it's after noon:
SELECT date_column
FROM yourTable
WHERE DATE(DATE_SUB(NOW(), INTERVAL 12 HOUR)) = DATE(date_column);
Edit:
The WHERE clause First gets the current time (NOW()) and subtracts 12 hours. This wont affect the date unless the time is before 12. This means DATE_SUB(NOW(), INTERVAL 12 HOUR) gives us today if it's after noon and yesterday if it's before.
We then check if the date_column matches the date we've created (using the DATE function so that the time is ignored).
Adding some rows to the SELECT may help you see how these dates are built up.

How to check if date is in range regardless of the year

I'm wondering what would be the easiest way in MySQL to check if given date is in range regardless of the year.
In database table I have two DATE fields: start and finish stored in YYYY-mm-dd
if start = 2013-11-01 and finish = 2014-03-01 anything between 1st of November and 1st of March of any year should be accepted.
Valid dates:
2020-01-01 1980-02-28
Invalid dates:
2013-10-30 1968-07-30
There are almost certainly cleaner ways of doing it, however this should work:
((DAYOFYEAR(finish_date) > DAYOFYEAR(start_date)
AND (DAYOFYEAR(#date) >= DAYOFYEAR(start_date)
AND DAYOFYEAR(#date) <= DAYOFYEAR(finish_date)))
OR (DAYOFYEAR(finish_date) <= DAYOFYEAR(start_date)
AND (DAYOFYEAR(#date) >= DAYOFYEAR(start_date)
OR DAYOFYEAR(#date) <= DAYOFYEAR(finish_date))))
For a start date in Oct 2012 and end date in Nov 2020 this will return all dates in the Oct-Nov range. If in fact would want it to return all Dates when the range is greater than a year (and hence covers all dates of the year) you could add:
OR DATEDIFF(Day, start_date, finish_date) > 356
before the final bracket.
use DAYOFYEAR:
When the Start Date is earlier in the year than the Finished Date:
the tested Date should lye between Start Date and Finish Date (or on Start or Finish)
When the Finished Date is earlier in the year than the Start Date:
the tested Date should lye outside the Start Date and Finish Date (or on Start or Finish)
You can use some date extract function and then check your condition..
for example.
SELECT EXTRACT(MONTH FROM TIMESTAMP '2013-11-01 20:38:40');
this will give ouput start month as 11
SELECT EXTRACT(MONTH FROM TIMESTAMP '2014-03-01 20:38:40');
this will give ouput end month as 3
now you can check the condition from above two result..
SELECT * FROM tableWithDates t WHERE month(t.start) >= 11 AND month(t.finish) < 3
if you want the first of march it will go like this:
SELECT * FROM tableWithDates t WHERE month(t.start) >= 11 AND (month(t.finish) < 3 OR month(finish) <= 3 AND day(finish)<=1)
Depending on the size of the data you will run this at. You can get into performance problems, as MySQL can't use indexes of calculated columns.
If you run into this i suggest spitting the month AND/OR day into separate columns.
Edit:
Given an one parameter input as '2008-02-29'
SELECT * FROM tableWithDates t
WHERE
month(t.start) >= month('2008-02-29') AND day(t.start) >= day('2008-02-29')
AND month(t.finish) <= month('2008-02-29') AND day(t.finish) <= day('2008-02-29')