Hi I'm writing queries for MySQL, and now my database has a column containing the timestamp in this format: 7/14/2015 7:57:49 AM, but I need to use the DATEDIFF function, so how can I convert the timestamp into the format like: 2015-7-14 (or 2015-07-14, I'm not sure which one is correct; just the date)?
This should convert your string to just the date in a date format, then you can use DATEDIFF on the date fields in question:
SELECT STR_TO_DATE(LEFT(t,LOCATE(' ',t) - 1), '%m/%d/%Y') FROM my_table;
The LEFT function will take the substring to the left of the space, which is just your date, then STR_TO_DATE will convert that substring to a date the system can use.
(Not knowing your field and table names, I used t and my_table.)
You don't need to. The way MySQL displays timestamps has nothing to do with the way they're stored internally; as long as it's TYPE TIMESTAMP or some compatible type, the DATEDIFF() function will know what to do with it.
TIMESTAMPs are actually stored as a really huge integer representing (I think) milliseconds from Midnight UTC, January 1st, 1970. The display format is determined by a system global variable, and has nothing to do with the actual value.
Converting from a string to a DATETIME or TIMESTAMP is actually also fairly straightforward using the STR_TO_DATE() function; in your case the format string would be something like
STR_TO_DATE('%c/%e/%Y %l:%i:%s %p', datecol)
although you might have to experiment a bit to make it work reliably.
Related
Is there a way to convert a string such as "-1 week" or "-5 minutes" into a datetime value in MySQL similar to php's extremely convenient strtotime() function?
I have a table that stores a human-readable time interval (such as "2 minutes") in one column and a datetime in another column.
I would like to select the rows where more than the amount of time specified in interval has elapsed since datetime.
MySQL doesn't have an equivalent of PHP's strtotime() in the sense that there is nothing that will automatically attempt to parse and determine the format of a date string using by assuming multiple formats.
What it does have is STR_TO_DATE(str,format) which requires you specify the format of your date, time or date + time string. It is the equivalent of PHP's date_create_from_format(format, str) function (though the format of the format parameter are different).
Here are some examples given from the MySQL documentation. They show a date being passed along with the format string that lets it know how the date string is to be interpreted:
SELECT STR_TO_DATE('01,5,2013','%d,%m,%Y');
SELECT STR_TO_DATE('May 1, 2013','%M %d,%Y');
Alternatively, you can cast a string to a date, time or datetime type, but they require a specific format (YYYY-MM-DD hh:mm:ss.fraction) for it to work:
SELECT CAST("2019-11-21" AS DATE);
If you deviate too far from that format it will make a few assumptions but could produce an incorrect date.
I am pretty new to MySQL, and am looking at a table (through a query) that has three date fields. However, they appear to be in seconds (but I could be wrong), but ultimately, I need to convert them to a valid date/time.
The numbers are:
1366272682
1366239600
1366272682
I think one of these dates is 18th April 2013.
Can someone let me know how I can convert them within the query (or indeed if I am right).
Thank you.
Those "numbers" are actually Unix Timestamps. Use FROM_UNIXTIME() to convert them into human friendly formats:
Returns a representation of the unix_timestamp argument as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS.uuuuuu format, depending on whether the function is used in a string or numeric context.
For example:
SELECT FROM_UNIXTIME(1366272682, '%e%D %M %Y')
I have this query
SELECT *
FROM `users_profile`
WHERE DATE_FORMAT(dob,'%d-%m-%Y') BETWEEN '05-03-1996' AND '05-03-1915'
which should return two results which both have these dates in the dob column
08-02-1996
14-02-1996
But it dosen't return anthing!! What am I doing wrong!!??
Why would you take a perfectly good date and convert it to a (bad) string for comparison?
Do the comparison as dates and put the constants in the right order:
SELECT *
FROM `users_profile`
WHERE dob BETWEEN date('1915-03-05') and date('1996-03-05');
Also note that I changed the date format for the date constants to YYYY-MM-DD. This is the ISO standard format for dates. (Despite that), it is a really good idea to use.
I am assuming that dob really is a date, because that is what the function date_format() takes for its first argument.
I need to convert varchar string data to time format in mysql.
For example,
I have a varchar column in table which stores time. The accepted values should be like 9:30 AM or 1200 PM. But currently it has either blank values or it has values like 9.30am or 12:00
There are many records like this, so cannot update manually.
Ithere any work around or function or procedure to do so?
please help.
Thanks
You can use the STR_TO_DATE() MySQL function to convert any string to a date.
Additionally you can use TIME() to extract the time portion of a datetime. A combination of both function is used to convert an arbitrary date string to a datetime and then you can extract the time portion from it as a valid MySQL TIME.
By default MySQL functions follow standard format but custom format can be specified and if your values don't use the international formats you'll need to check with the documentation and provide the format your system is using.
The main problem is, that I have stored in database datetime , not the date (what I need). Ok never mind.
I have thousands of reports stored each day.
I need to LEFT by 10 my datetime_view (to cut the time) and everything's fine. Except this. I'm trying to figure out why do I have to put in the condition + one day from the future? Otherwise it won't search what I want.
SELECT
LEFT(datetime_view,10),
count(type)
FROM reports
WHERE
type IN (1,2,5)
AND
datetime_view>='2012-10-28'
AND
datetime_view<='2012-11-04'
group by LEFT(datetime_view,10);
You can see I must search from the future. Why??
It gives me an output from 28.10 to 3.11 ....
don't use string operations on date/time values. MySQL has a huge set of functions for date/time manipulation. Try
GROUP BY DATE(datetime_view)
instead, which will extract only the date portion of the datetime field. Your string operation is not y10k compliant. Using the date() function is.
As for your plus one day, consider how the comparisons are done: A plain date value, when used in date/time comparisons, has an implicit 00:00:00 time value attached to it, e.g. all dates have a time of "midnight".
i think it's better to use DATE(datetime_view) to cut the time instead of LEFT(datetime_view,10), also on the where condition:
DATE(datetime_view) <= '2012-11-03'