For the leave application, FROM date and TO date is given by selecting the dates from calender. I have these two dates in mysql.I want to calculate number of days for the leave. So Person applying leave from July 1 to July 5 th. So total 5 days.
But when i use DateDiff(to, date) it gives 4.
How can i get 5 days?
select datediff('2015-07-05','2015-07-01');
You may simply do +1, as you already notice, DATEDIFF excludes starting date, see example below:
select (datediff('2015-07-05','2015-07-01') + 1) as days
DATEDIFF(expr1,expr2)
DATEDIFF() returns expr1 − expr2 expressed as a value in days from one date to the other. expr1 and expr2 are date or date-and-time expressions. Only the date parts of the values are used in the calculation.
example
SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30');
output : 1
or
SELECT DATEDIFF('2010-11-30 23:59:59','2010-12-31');
Output : 31
You can add manual plus 1
If you closely look at datediff function,
when you use two same dates, it will give you 0 days as a difference, not 1.
select datediff('2015-07-01','2015-07-01');
Will give you 0 days.
So its obvious that you will get one less day as it starts with 0 difference for same date.
datediff will return difference between two dates however you need to include both the dates while calculating the number of leaves. You should use value returned from datediff + 1.
Related
This is a question from leetcode, using the second query I got the question wrong but could not identify why
SELECT
user_id,
max(time_stamp) as "last_stamp"
from
logins
where
year(time_stamp) = '2020'
group by
user_id
and
select
user_id,
max(time_stamp) as "last_stamp"
from
logins
where
time_stamp between '2020-01-01' and '2020-12-31'
group by
user_id
The first query uses a function on every row to extract the year (an integer) and compares that to a string. (It would be preferable to use an integer instead.) Whilst this may be sub-optimal, this query would accurately locate all rows that fall into the year 2020.
The second query could fail to locate all rows that fall into 2020. Here it is important to remember that days have a 24 hour duration, and that each day starts at midnight and concludes at midnight 24 hours later. That is; a day does have a start point (midnight) and an end-point (midnight+24 hours).
However a single date used in SQL code cannot be both the start-point and the end-point of the same day, so every date in SQL represents only the start-point. Also note here, that between does NOT magically change the second given date into "the end of that day" - it simply cannot (and does not) do that.
So, when you use time_stamp between '2020-01-01' and '2020-12-31' you need to think of it as meaning "from the start of 2020-01-01 up to and including the start of 2020-12-31". Hence, this excludes the 24 hours duration of 2020-12-31.
The safest way to deal with this is to NOT use between at all, instead write just a few characters more code which will be accurate regardless of the time precision used by any date/datetime/timestamp column:
where
time_stamp >= '2020-01-01' and time_stamp <'2021-01-01'
with the second date being "the start-point of the next day"
See answer to SQL "between" not inclusive
I want to get the previous month date for specific dates in SQL. For example: 6.21.19 has a previous month date of 5.21.19.
I am just trying to get comps from this.
MONTH( curdate() ) -1
I need to return the previous month date.
Welcome to the board Arie. Judging from your question and responses, you need a range of dates and their prior month relations. The easiest way would be for all of the dates you need to look up to be in a table, then the answers provided so far would work. Since that doesn't appear to be the case, I'm guessing you are creating date ranges on the fly.
So lets assume you need exactly the data shown in your example, there are two parts to this, first you need to get a list of days that you want to look up, then you need to get the day in the prior month. There are lots of ways to get a sequence of days, but for simplicity I'll use a recursive CTE. Once I have the date range, I'll just select the dates and their prior month date as well.
with Date_CTE as (select cast('6/1/2019' as datetime) as repDate
union all
select dateadd(day, 1, repdate) as repDate
from Date_CTE
where repDate < '06/07/2019')
select repDate, dateadd(month, -1, repDate) as PriorDate
from Date_CTE
CTEs are helpful functions and you can get more details on them here, but it's worth noting there are many ways to do this. Hope this gets you pointed in the right direction.
SELECT yourDateColumn, yourDateColumn-interval 1 month as prevMonthDate
I need to get number of days between 2 dates, a given one and current date.
But in pure SQL, I mean without usign functions, it is possible?
For exaple
SELECT days (t.givenDate) - days (current date) FROM table t
Have you any idea?
Thaks a lot.
The built-in function is datediff(). The equivalent for the above is:
SELECT datediff(t.givenDate, curdate()) FROM table t;
Normally, givenDate would be in the past and you would want the arguments in the other order.
I want to do something like this:
select datediff('2010-01-21',(select date_of_birth from people));
and take as result the difference from each date_of_birth.
You can use datediff to get Difference in terms of day or specified format (either month, week year, days etc)
select datediff(DAY,'2010-01-21',date_of_birth)
from people
I have some records in a query with a column of dates. I want it to only show the records that occur in March. This link
https://support.office.com/en-US/Article/Examples-of-query-criteria-3197228c-8684-4552-ac03-aba746fb29d8#bm1 shows the different types of criterion.
The one below in the table describes how to show only what occurs in a particular month:
"Contain a date that falls in a specific month (irrespective of year), such as December
DatePart("m", [SalesDate]) = 12
Returns records where the transactions took place in December of any year."
I don't know what the SalesDate means in the criteria function, and there isn't any explanation on the page.
[SalesDate] implied a Date/Time field named SalesDate. If your Date/Time field is named something else, such as invoice_date, substitute that name in the DatePart expression:
DatePart("m", [invoice_date]) = 12
For March instead of December invoices, use this:
DatePart("m", [invoice_date]) = 3
You could also use Month() instead of DatePart to get the same result:
Month([invoice_date]) = 3