I have a MySQL DB table with multiple date type fields. I need to do different SELECT queries on this table but I am not sure which way is the best to find records from the same month.
I know I can do the following:
SELECT *
FROM table
WHERE MONTH(somedate) = 5
AND YEAR(somedate) = 2015
But I keep reading that isn't efficient and that I should go with using actual dates, i.e.
SELECT *
FROM table
WHERE somedate BETWEEN '2015-05-01' AND '2015-05-31'
However, all I would have is the month and the year as variables coming in from PHP. How do I easily and quickly calculate the last day of the month if I go with second option?
Don't calculate the last day of the month. Calculate the first day of the next month instead.
Your query can be like this
WHERE t.mydatetimecol >= '2015-05-01'
AND t.mydatetimecol < '2015-05-01' + INTERVAL 1 MONTH
Note that we're doing a less than comparison, not a "less than or equal to"... this is very convenient for comparing TIMESTAMP and DATETIME columns, which can include a time portion.
Note that a BETWEEN comparison is a "less than or equal to". To get a comparison equivalent to the query above, we'd need to do
WHERE t.mydatetimecol
BETWEEN '2015-05-01' AND '2015-05-01' + INTERVAL 1 MONTH + INTERVAL -1 SECOND
(This assumes that the resolution of DATETIME and TIMESTAMP is down to a second. In other databases, such as SQL Server, the resolution is finer than a second, so there we'd have the potential of missing a row with value of '2015-05-31 23:59:59.997'. We don't have a problem like that with the less than the first day of the next month comparison... < '2015-06-01'
No need to do the month or date math yourself, let MySQL do it for you. If you muck with adding 1 to the month, you have to handle the rollover from December to January, and increment the year. MySQL has all that already builtin.
date('t', strtotime("$year-$month-01")) will give days in the month
Related
I need help with the MySQL query. I have a table like this in MySQL
What I want is to get the last 3 months' records from the table. But I don't understand how to make this MySQL query.
I have tried to contact both columns and tried to generate a MySQL date to compare but it returns me null.
I also tried this query and it works for current data. But i am not sure if it is the only way to do this or is there any better way.
What I want is to get the last 3 months' records from the table.
I think you want a where clause like this:
date(concat_ws('-', salary_year, salary_month, 1)) >= (curdate() - interval (1 - day(curdate()) day) - interval 2 month
The key idea here is to convert the string to a date so it is handled correctly.
If you have a fixed date, then you would represent that as:
date(concat_ws('-', salary_year, salary_month, 1)) >= '2021-04--01'
I currently have a query that is getting the records where their deadline is less than 3 months away. The deadline is stored as a Date, but the year is not important as this record should flag up every year.
My query:
SELECT client_name
FROM client
WHERE MOD(DAYOFYEAR(deadline) - DAYOFYEAR(CURDATE()), +365) <= 90
AND DAYOFYEAR(deadline) > DAYOFYEAR(CURDATE())
Apologies if there’s errors in the syntax as I’m writing this from memory – but it does work.
It works up until a deadline is in the first quarter and the current date is in the final quarter then it no longer returns the record. How do I get around this?
So the query needs to return the records that have a deadline within 3 months of the current date. The Year in the deadline date should be ignored as this could be years ago, but it is the day and month of the deadline that is important.
Or is the problem the date I am storing? Should I update this each year?
Thanks
One approach is to use a conditional test like this:
WHERE CONCAT(YEAR(NOW()),DATE_FORMAT(d.deadline,'-%m-%d'))
+ INTERVAL CONCAT(YEAR(NOW()),DATE_FORMAT(d.deadline,'-%m-%d'))<NOW() YEAR
< NOW() + INTERVAL 3 MONTH
We can unpack that a little bit. On that first line, we're creating a "next due" deadline date, by taking the current year, and appending the month and day value from the deadline.
But there's a problem. Some of those "next due" deadline dates are in the past. So, to handle that problem (when the 3 month period "wraps" into the next year), we need to add a year to any "next due" deadline date that's before the current date.
Now, we can compare that to a date 3 months from now, to determine if the "next due" deadline date is in the next 3 months.
That's a bit complicated.
Here's a SQL Fiddle as a demonstration: http://sqlfiddle.com/#!2/c90e9/3.
For testing, NOW() is inconvenient because it always returns today's date. So, for testing, we replace all occurrences of NOW() with a user-defined variable #now, and set that to various dates, so we can appropriately test.
Here's the SQL statement I used for testing. The first expression is the conditional test we're planning on using in the WHERE clause. For testing, we want to return all the rows, and just see which rows get due_in_3mo flagged as TRUE (1) and which get flagged as FALSE (0).
The second expression in the SELECT list just the "next due" deadline date, same as used in the first expression.
The rest of the expressions are pretty self-explanatory... we also want to display the date 3 months in the future we're comparing to, and the original "deadline" date value.
SELECT
CONCAT(YEAR(#now),DATE_FORMAT(d.deadline,'-%m-%d'))
+ INTERVAL CONCAT(YEAR(#now),DATE_FORMAT(d.deadline,'-%m-%d'))<#now YEAR
< #now + INTERVAL 3 MONTH
AS `due_in_3mo`
, CONCAT(YEAR(#now),DATE_FORMAT(d.deadline,'-%m-%d'))
+ INTERVAL CONCAT(YEAR(#now),DATE_FORMAT(d.deadline,'-%m-%d'))<#now YEAR
AS `next_due`
, d.id
, d.deadline + INTERVAL 0 DAY AS `deadline`
, #now + INTERVAL 3 MONTH AS `now+3mo`
, #now + INTERVAL 0 DAY AS `now`
FROM d d
CROSS
JOIN (SELECT #now := '2015-11-01') i
ORDER BY d.id
Change the value assigned to #now in the inline view (aliased as i) to test with other date values.
(You may want to use DATE(NOW()) in place of NOW() so that times don't get mixed in, and you may want to subtract another day from that, that really just depends how you want to handle the edge case of a deadline with month and day the same as the current date. (i.e. do you want to handle that as "in the past" or not.)
To summarize the approach: generate the "next due" deadline date as a DATE value in the future, and compare to the a date 3 months from now.
I have this query where I provide to-date & from date.
SELECT *
FROM sales
WHERE date between to-date AND from-date;
Now I want to execute this query with following parameters
to-date = Oct-2015
some-other-date = Oct-2015
That is I want records of the whole month.
How would I do that in a query where I have to and from dates provided it will work for both scenarios where months can be same and different as well.
Update:
dataType for column date is date
You can find the first day of the month containing any given timestamp with an expression like this. For example by using the timestamp NOW(), this finds the first day of the present month.
(DATE(NOW() - INTERVAL DAYOFMONTH(DATE(NOW()))
That's handy, because then you can use an expression like
(DATE(NOW() - INTERVAL DAYOFMONTH(DATE(NOW())) - INTERVAL 1 MONTH
to find the beginning of the previous month if you like. All sorts of date arithmetic become available.
Therefore, you can use an expression like the following to find all records with item_date in the month before the present month.
WHERE item_date>=(DATE(NOW()-INTERVAL DAYOFMONTH(DATE(NOW()))- INTERVAL 1 MONTH
AND item_date < (DATE(NOW()-INTERVAL DAYOFMONTH(DATE(NOW()))
Notice that we cast the end of a range of time as an inequality (<) to the moment just after then end of the range of time.
You may find this writeup useful. http://www.plumislandmedia.net/mysql/sql-reporting-time-intervals/
It's often useful to create a stored function called TRUNC_MONTH() to perform the conversion of the arbitrary timestamp to the first day of the month. It makes your SQL statements easier to read.
select * from sales
where from-date >= 1-Oct-2015
and to-date <= 1-Nov-2015
Update
select * from sales
where date >= from-date
and date <= to-date
Here is SQLFIDDLE
You Can get month from your both to and from dates and find records of that month
SELECT * FROM sales
WHERE MONTH('2002-01-03') AND MONTH('2002-01-3')
SqlFiddle of Using Month Function
I am trying to get data from a database between 8PM (say, today) and 2AM tomorrow.
I have been using clauses such as where hour(date_field)>=20 and hour(date_field) <23 to obtain data in the same day.
Here the date_field is datetime
All I want is to be able to tell SQL to get data after 8PM today, increment the datefield and then get data till 2AM tomorrow.
Any help will be appreciated.
The normal pattern for retrieving rows based on a datetime range is perform comparisons on the bare column, comparing the column value to constants derived from expressions.
To get rows for a single contiguous range, 8PM today to 2AM tomorrow, for example:
WHERE t.date_column >= DATE(NOW()) + INTERVAL 20 HOUR
AND t.date_column < DATE(NOW()) + INTERVAL 26 HOUR
To unpack that a little bit: NOW() returns current datetime, the DATE() function truncates the time portion to midnight, then we add back in enough hours to get '8PM today', or enough hours to get '2AM tomorrow'.
If you are meaning to retrieve multiple "8PM to 2AM" periods, for a whole series of days.
First, you'd want an upper and lower bound of the date_column to be retrieved (unless you want every possible date)
WHERE t.date_column >= '2014-08-01 20:00:00'
AND t.date_column < '2014-10-02 02:00:00'
From that, we need to filter out all of the rows that aren't between 8PM and 2AM. One convenient way to do that would be to "subtract" two hours from the datetime col, and check for hour >= 6PM.
AND HOUR(t.date_column + INTERVAL -2 HOUR) >= 18
Note that the expression involving date_column will need to be evaluated for EVERY row in the table, unless there are some other predicates that filter rows out. With a suitable index available, MySQL can use an index range scan operation for predicates of the form date_column >= const and date_column < const. (It can't do that when the column is wrapped in a function or expression.)
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.