I am using DATE() function to calculate the difference between two dates in MySQL
value of SYSDATE() function is following
select SYSDATE();
2020-07-15 12:16:07.0
When I am using date from same month, it is giving correct result
select DATE(SYSDATE())- DATE('2020-07-13');
2
But when I am using date from last month it is giving difference as 86 instead of 16;
select DATE(SYSDATE())- DATE('2020-06-29');
86
Edit:
I am aware that we can use DATEDIFF() but I want to verify why DATE() function is giving results like this since we are already using this in code
MySQL doesn't support subtracting one date from another. The code
SELECT DATE '2020-07-15' - DATE '2020-06-29';
should hence result in an error, but MySQL silently converts this to this instead:
SELECT 20200715 - 20200629;
Seeing that you want to subtract two values, it assumes that you want to work with numbers. Dates are not numbers, but their internal representation yyyymmdd can be represented numerically. So, while CAST(DATE '2020-07-15 ' AS int) fails with a syntax error, as it should, MySQL is not consistent, when it comes to subtraction. It generates the numbers 20200715 and 20200629 and works with these.
I consider this a bug. MySQL should either raise an exception or return an INTERVAL when subtracting one DATE from another.
Related
In my database table, there is a date column i.e. EXPECTED DATE which is in dd-mm-yyyy format, and the datatype of the column is text. Now, I want to convert the format to yyyy-mm-dd. But the date is not changing at all and also when I tried to get the timestamp for the expected date column . I am getting some errors. For date coming I have used this STR_TO_DATE. But the year is not coming like what I expect and the timestamp also.
For example:
select STR_TO_DATE ('30-11-2011', '%d,%m,%y') as date ;
returns a result as
2020-11-30
And for timestamp
select STR_TO_DATE ('2011,11,30 12,30,45', '%y,%m,%d, %H,%I,%S');
I am not getting errors.
Please help me get the correct answers for this problem.
For the first query you need to use the %Y. Remember that it is always better to use "Y" for the years when you are writing a query for year.
SELECT STR_TO_DATE("30,11,2011", "%d,%m,%Y");
For the second one also, you can use '%Y' in the place of '%y'. For minutes, use '%i' not '%I'. For hours and minutes, you can use whatever you like.
SELECT STR_TO_DATE("2011,11,30 12,30,45", "%Y,%m,%d %h,%i,%s");
Refer to the below documentation for more clarification on SQL commands.
You need %Y (capital Y) for the 4 digit year, when using MySQL's STR_TO_DATE. Also, minutes is represented by %i, not %I, the latter which is hours on a 0 to 12 scale. So use:
SELECT STR_TO_DATE('30-11-2011', '%d-%m-%Y');
SELECT STR_TO_DATE('2011,11,30 12,30,45', '%Y,%m,%d %H,%i,%S');
For the first query you need to use the %Y'.
SELECT STR_TO_DATE("30,11,2011", "%d,%m,%Y");
For minutes, use this one only '%i'.
SELECT STR_TO_DATE("2011,11,30 12,30,45", "%Y,%m,%d %h,%i,%s");
Whenever I'm using OR in where condition my query is putting date_format() it's working but when I'm using AND it's working fine.
True Query:
SELECT * FROM `tbl_inquiry_trans`
WHERE date_format(follow_updatetime,'%Y-%m-%d') >= '2018-08-02'
AND date_format(follow_updatetime,'%Y-%m-%d') <= '2018-08-02'
AND emp_id=2 or user_id=2
The above query should display specific date data but it's showing all dates data.
Test Query:
SELECT * FROM `tbl_inquiry_trans`
WHERE date_format(follow_updatetime,'%Y-%m-%d') >= '2018-08-02'
AND date_format(follow_updatetime,'%Y-%m-%d') <= '2018-08-02'
AND emp_id=2
When I'm using AND it's showing expected date data but I want to use OR in the where clause.
The and logical operator has a higher precedence than the or operator (i.e., and expressions are evaluated before or expressions, in a similar way you'd calculate a multiplication before calculating an addition in an arithmetic expression). In order to achieve the behavior you wanted, you need to surround the two sides of the or operator with parenthesis:
SELECT *
FROM tbl_inquiry_trans
WHERE date_format(follow_updatetime,'%Y-%m-%d')>='2018-08-02' AND
date_format(follow_updatetime,'%Y-%m-%d')<='2018-08-02' AND
(emp_id=2 OR user_id=2) -- Here
Same answer as #Mureinik, except that I don't think you need to those calls to DATE_FORMAT, because in MySQL it is possible to directly compare dates against string literals. So, the following should suffice:
SELECT *
FROM tbl_inquiry_trans
WHERE
follow_updatetime >= '2018-08-02' AND follow_updatetime < '2018-08-03' AND
(emp_id = 2 OR user_id = 2);
The logic in the above check on follow_updatetime is that any date would match if it were on or after midnight of 2018-08-02 or strictly before midnight of 2018-08-03. This would cover the entire day of 2018-08-02. This version of doing it is preferable to what you had, because it makes it possible to use an index on the follow_updatetime column.
I'm having a problem working with a Navicat Database. I got a column in SQL called fechaNacimiento (Birthdate) that should be a Date type, but instead it's stored as integers (most negative integers):
SELECT fechaNacimiento FROM Registrados
And I'm getting:
fechaNacimiento
-1451678400
-2082829392
-1798746192
-1199221200
-1356984000
-694299600
-1483214400
-1924976592
-1830368592
-2019670992
-1678909392
239252400
1451617200
-879541200
I don't know how this dates where loaded, I just know that inside that negative integer there's a date, and nobody here have any clue about how to spell SQL, so I have nobodoy to ask. If I just cast it to DATETIME, I get all of them as NULL values. Any idea in how to convert this data to Date type?
Numbers like that make me think of Unix times, number of seconds since 1970. If so, you might be able to do:
select dateadd(second, <column>, '1970-01-01')
This would put the negative values sometime before 1970 (for instance, -1678909392 is 1916-10-19). If you have older dates, then that might be the format being used.
These might also be represented as milliseconds. If so:
select dateadd(second, <column>/1000, '1970-01-01')
In this case, -1678909392 represents 1969-12-12.
In MySQL, you would use:
select '1970-01-01' + interval floor(column / 1000) second
how to return exactly rows between two dates with timestamps
this code didn't return all row between 01-04 and 07-05
so what is the problem and why it didn't work correctly
and how to select rows between two date with timestamp when i use date
format like this 01-04-2015
SELECT d_send_items.si_id ,
DATE_FORMAT(FROM_UNIXTIME(d_send_items.si_send_date), '%d-%m-%Y')
FROM d_send_items WHERE
DATE_FORMAT(FROM_UNIXTIME(d_send_items.si_send_date), '%d-%m-%Y') BETWEEN '01-04-2015' AND '07-05-2015'
date_format returns a string, so between is using string comparisons to figure out whether the values are between those two you provide.
So, unless your date format is something like yyyy-mm-dd, between is not going to work as you expect.
For example, the date 08-04-2015 is between the two dates 01-04-2015 and 07-05-2015 but the string 08-04-2015 is not between the two strings 01-04-2015 and 07-05-2015, because the most significant portion 08 is beyond the range which terminates at 07....
So you could use:
where
date_format(from_unixtime(d_send_items.si_send_date), '%Y-%m-%d')
between '2015-04-01' and '2015-05-07'
but per-row functions never scale well in relational databases.
If they're proper timestamp fields, I think you can also bypass the conversion and use something like:
where d_send_items.si_send_date >= '01-04-2015'
and d_send_items.si_send_date < '08-05-2015'
(noting the < day following bit for the second conditional since 08-05-2015 is the same as 08-05-2015 00:00:00) assuming MySQL will recognise those date formats as dd-mm-yyyy.
However, even if it doesn't and you have to use some function to turn those string into timestamp values, this is something that would be done once for the whole query rather than (most likely) for every single row.
I have a two date columns, dateA and dateB. If I subtract dateA from dateB (dateB - dateA), I get wrong results but not using DATEDIFF(dateB,dateA)function. I get wrong result from direct subtraction when used in a table with data but not with below query.
SELECT DATE('2013-01-31') - DATE('2013-01-27')
Why?
EDIT:
I found that in MySQL if the two dates are within a month then direct subtraction gives correct result but if the dates span month, year there might be a problem.
Am I right?
Presumably, you columns are not stored as dates, but as strings. If they were stored as dates, then subtraction would work as expected.
When you subtract two strings, such as:
SELECT '2013-01-31' - '2013-01-27'
Then MySQL converts them to numbers, based on the leading digits. In this case, both start with the numbers 2013, so both are converted to 2013 (if there were no digits at the beginning then the value would be 0). These numbers are then subtracted.
Are your column's defined as date, or as Varchars? Because Date as a String means nothing. When you do a DATE('2013-01-31'), it creates a date object and hence the subtraction works. So, if your column is defined as Varchar, do DATE(dateB) - DATE(dateA).