MySQL - calculate start and end date of months - mysql

I have table months:
id name
=============
1 January
2 February
3 March
.. ........
I have the year stored in a variable:
SET #year = YEAR(CURDATE());
I now want 2 new columns: start_date and end_date - both of these columns will contain the start date and end date of the month based on the id and #year variable. This will be in the standard MySQL date column format. Currently I have this:
CONCAT(#year, '-', LPAD(months.id, 2, '0'), '-', '01') AS start_date,
CONCAT(#year, '-', LPAD(months.id, 2, '0'), '-', '31') AS end_date
This does work but is there a better/cleaner way? Is there a way to automatically get the actual last day of the month?

You can get the first day of the year using date() and strings. The rest can be done using date functions and operators:
select m.*,
date(concat(year(curdate()), '-01-01')) + interval (id - 1) month as month_start,
last_day(date(concat(year(curdate()), '-01-01')) + interval (id - 1) month) as month_end
from months m;
Here is a small db<>fiddle.

Related

SQL: Query periods of time given date

I have a list of periods during a year, and they are the same every year. You can think of it as a Season. They have a startDate and a endDate.
Because there can be Seasons that leap each other, what I need to to is query all the matching Seasons given a date, no matter what year.
As an example:
Season1: from 1st of January to 10th of January
Season2: from 6th of January to 8th of January
Season3: from 11th of January to 20th of January
Given the date 7th of January, I'd need to retrieve the Season1 and Season2.
I've tried converting all dates to the same year, but It doesn't work when the Start Date of a season in "later" than the End Date (for example, there's a period starting on November and ending of February).
Thanks in advance for the help.
Edit, sample data:
StartDate EndDate SeasonId
2000-08-01 2000-08-31 4
2000-12-29 2000-01-02 3
2000-06-01 2000-07-30 3
2000-09-01 2000-09-30 3
2000-01-06 2000-01-08 3
2000-04-07 2000-04-17 3
2000-04-28 2000-05-01 3
2000-06-02 2000-06-05 3
2000-06-23 2000-06-25 3
2000-09-08 2000-09-11 3
2000-09-22 2000-09-25 3
2000-10-12 2000-10-15 3
2000-11-01 2000-11-05 3
2000-12-01 2000-12-10 3
2000-12-22 2000-12-26 3
2000-03-01 2000-05-31 2
2000-10-01 2000-10-31 2
2000-11-01 2000-02-28 1
And I'd need, for example, the season for the date 2000-02-08, and retrieve seasonId = 1, or the date 2000-10-13and retrive seasonId = 3, seasonId = 2
I would do it in 2 'options': (the following SQL assumes you already got rid of the year in the table, and left only month-date format. )
select ... from seasons s where
(s.startDate <= s.endDate and s.startDate <= #mydate and s.endDate >= #mydate) or
(s.startDate > s.endDate and s.startDate >= #mydate and s.endDate <= #mydate)
You could query like this for the Season1:
select * from myTable where (month(myDate) = 1 and DAY(myDate) between 1 and 10)
If you have a season in more than one month, like start date January 20th, and finish date Febrery 10th, you could query this way:
select * from myTable where (month(myDate) = 1 and DAY(myDate) >= 20) or (month(myDate) = 2 and DAY(myDate) <= 10)
UPDATED WITH YOUR UPDATE
It is a little bit tricky, but it should work...
select * from seasons_table
where cast(cast(day(myDate) as char) + '/' + cast(month(myDate) as char) + '/' + '2000' as date) between
cast(cast(day(StartDate) as char) + '/' + cast(month(StartDate) as char) + '/' + '2000' as date) and
cast(cast(day(EndDate) as char) + '/' + cast(month(EndDate) as char) + '/' + '2000' as date)
given tblSeason with columns Id, startdate, enddate and your date as #myDate you would query as
Select Id From tblSeason WHERE #myDate BETWEEN startdate AND enddate
would give list of Id's of the seasons that match.
if you can't work from that, please give more information in your examples as to the structure you are querying and the expected outcome.
*Edit to ignore the year part you could do similar to
Declare #myDate datetime = '2016-10-13'
SELECT [StartDate]
,[EndDate]
,[SeasonId]
FROM [dbo].[Table_1]
where DATEPART(dy, #myDate) >= DATEPART(dy,StartDate)
AND (DATEPART(dy,#myDate) =< DATEPART(dy,EndDate) OR DATEPART(dy,StartDate) > DATEPART(dy,EndDate))
Why are you including the year in the table? That seems strange.
In any case, you only care about the MM-DD format, so use date_format() to convert the values to strings:
select t.*
from t
where (start_date <= end_date and
date_format(#date, '%m-%d') >= date_format(start_date, '%m-%d') and
date_format(#date, '%m-%d') <= date_format(end_date, '%m-%d')
) or
(start_date > end_date and
date_format(#date, '%m-%d') <= date_format(start_date, '%m-%d') and
date_format(#date, '%m-%d') >= date_format(end_date, '%m-%d')
);
The strings are fine for comparison, because you are only looking at the month and day components of the date.
Given the nature of your problem, I would recommend that you store start_date and end_date in a non-date format, such as MM-DD.

Parse date together using 1 database field

I am trying to parse a date together for the previous fiscal year. The fiscal year start month is stored in our database as FiscalYearStartMonth.
This is what I had, but it doesn't work.
CONVERT(varchar,dateadd(year,0,CONVERT(varchar,Year(GetDate())+ FiscalYearStartMonth + '01',106)))
Any suggestions?
This will give you the start of your fiscal year in the current year
SELECT CONCAT(YEAR(NOW()), '-', FiscalYearStartMonth, '-01');
If you want to find the date in the past, I'm afraid my answer is a bit complicated. I'm sure there is a better solution:
SELECT date
FROM (
SELECT CONCAT(YEAR(NOW()), '-', FiscalYearStartMonth, '-01') AS date
UNION ALL SELECT CONCAT(YEAR(NOW()) - 1, '-', FiscalYearStartMonth, '-01')
) AS dates
WHERE date < NOW()
ORDER BY date DESC
LIMIT 1;

How Can I Get The Next 1st December Date?

I have a date field in my MySQL table and I want to get all rows before the next 1st Of December. So for example the rows I should get back if I run the query today (Nov 2015) would be any date before 1st Dec 2015. If I run the query after 1st Dec 2015 but before 1st December 2016, it should return all rows with a date of before 1st Dec 2016.
Sorry for lack of code, I have literally no idea where to start with this one!
I create the limit date based on the current month (using now() to get the current date). If the current month is 12, then the limit is 1-12 of next year (year(now()+1), otherwise the current year.
select YourDate
from YourTable
where YourDate <
case when month(now())=12 then
date(concat(convert(year(now()+1), char), '-12-01'))
else
date( concat(convert(year(now()), char), '-12-01'))
end;
I think you should use something like this:
SELECT *
FROM Table T
WHERE Some_Date < CASE
WHEN MONTH(CURDATE()) < 12 THEN STR_TO_DATE('01, 12, ' + YEAR(CURDATE())),'%d,%m,%Y')
ELSE STR_TO_DATE('01, 12, ' + YEAR(CURDATE() + 1)),'%d,%m,%Y')
END
Disclaimer: I dont have mysql, so I couldn't test it.
I did manage my own solution too
SELECT *
FROM table
WHERE date < DATE_ADD( MAKEDATE( IF( MONTH( CURRENT_DATE() ) < 12, YEAR( CURRENT_DATE() ), YEAR( CURRENT_DATE() + INTERVAL 1 YEAR ) ), 1), INTERVAL + 11 MONTH )

Last date in quarter MySQL

I have a table with some dates. I need a query which will return the max (last) date from this table and last date of quarter this max date belongs to.
So for data i table
ID| EDATE
--+----------
1|2014-03-06
2|2014-10-12
this query should return 2014-10-12 and 2014-12-31.
As I understand you want the last day of the quarter, so 31 March, 30 June, 30 Sept, 31 Dec? So you can use the answer from Gordon Linoff and adjust it to do that.
You only need a case statement on month(date) and concat that with the year.
http://dev.mysql.com/doc/refman/5.1/de/control-flow-functions.html
str_to_date(
concat(
year(edate),
(case
when month(edate) in (1, 2, 3) then '-03-31'
when month(edate) in (4, 5, 6) then '-06-30'
when month(edate) in (7, 8, 9) then '-09-30'
else '-12-31'
end)
),
'%Y-%m-%d'
)
Getting the day of the last quarter for the date is a bit yucky, but possible. Here is a sort of brute force solution:
select edate,
str_to_date(concat(year(edate), '-', 1 + floor((month(edate) - 1)/ 3)) * 3, '-',
(case when month(edate) in (1, 2, 3, 10, 11, 12) then 31 else 30 end)),
'%Y-%m-%d'
)
from table t
order by edate desc
limit 1;
Here is a SQL Fiddle that demonstrates it.
You can use LAST_DAY to select the last day of a specific month depending on where your quarters end you may have to change the 3,6,9,12 to different months.
select t1.max_date,
(
case
when month(max_date) <= 3
then last_day(concat(year(max_date),'-3-1'))
when month(max_date) <= 6
then last_day(concat(year(max_date),'-6-1'))
when month(max_date) <= 9
then last_day(concat(year(max_date),'-9-1'))
else last_day(concat(year(max_date),'-12-1'))
end
) last_quarter_day
from (
select max(EDATE) max_date from myTable
) t1
I found the simplest answer:
SELECT MAKEDATE(YEAR(edate),1)
+ INTERVAL QUARTER(edate) QUARTER
- INTERVAL 1 DAY
This query takes the first day of year, adds quarters to it and subtracts 1 day to get the last day in wanted quarter. So the required query should look like:
SELECT MAX(edate),
MAKEDATE(YEAR(MAX(edate)),1)
+ INTERVAL QUARTER(MAX(edate)) QUARTER
- INTERVAL 1 DAY
FROM table

Create Date from two cols in mySql

I have a table in my database with two columns: month (1-12) and year (yyyy).
I need to select records between two dates, for exemple
select * from Calendar a where SOMEDATE between STARTDATE and ENDDATE.
So the question is: how can I create the STARTDATE and the ENDDATE from this two columns I have?
...where SOMEDATE between
STR_TO_DATE(CONCAT_WS('-',STARTYEAR,STARTMONTH,1),'%Y-%m-%d')
and
DATE_SUB(
STR_TO_DATE(CONCAT_WS('-',ENDYEAR,ENDMONTH + 1,1),'%Y-%m-%d')
, INTERVAL DAY 1
)
Note that we convert both parts to type date, and use date_sub to subtract a single day from ENDMONTH + 1, since we don't know how many days there are in the relevant month.
You can use this solution to make date from the year and month fields-
SELECT MAKEDATE(year, 1) + INTERVAL month - 1 MONTH FROM calendar;
The apply this one to WHERE condition, e.g. -
SELECT * FROM Calendar a
WHERE
MAKEDATE(year, 1) + INTERVAL month - 1 MONTH BETWEEN
#STARDATE - INTERVAL EXTRACT(DAY FROM #STARDATE) - 1 DAY
AND
#ENDDATE
But I have to ask you about the STARTDATE and ENDDATE criterias. What to do if STARTDATE is '2012-09-20'? Should the query return records with month = 9?