I have a weird problem in mysql!
my query is
SELECT * FROM aa WHERE problemTime>= '2016/03/20' AND problemTime<= '2016/04/20'
the result of this query is nothing , but when I change the first time to 2016/03/19 or 2016/03/21 I have the following result! I mean these queries
SELECT * FROM aa WHERE problemTime>= '2016/03/21' AND problemTime<= '2016/04/20'
or
SELECT * FROM aa WHERE problemTime>= '2016/03/19' AND problemTime<= '2016/04/20'
the result in both time ( 19th and 21th) is
but when I use 20th the result is noting
my main table is
I change the format of time from 2016/03/20 to 2016-03-20 ( I mean change / to - ) but it doesn't have change too!
whats the problem?
You should really be running a query like this if your problemTime column is datetime type:
SELECT * FROM aa
WHERE
problemTime>= str_to_date('2016/03/20', '%Y/%m/%d') AND
problemTime <= str_to_date('2016/04/20', '%Y/%m/%d')
Don't rely on implicit conversions between string and date.. leave your table data alone and ensure you explicitly convert your where clause parameters to the same data type as in the table. Also remember that a date "without" a time is actually midnight on the day in question, and midnight is like zero, it's the first thing that happens on any given day. A time of 6am on a given date, is after midnight, so a query that asks for dates less than or equal to midnight on a particular date means the 6am date will be excluded
This is general good DB practice; do not convert table data where possible, because it can cause huge performance hits and wrong results
Your column "problemTime" have date with time. Do not convert table data, change your where clause (add time).
SELECT * FROM aa WHERE problemTime>= '2016/03/20 00:00:00' AND problemTime<= '2016/04/20 23:59:59'
Try this as per SQl Server.
SELECT * FROM aa
WHERe cast(problemTime AS date) between '2016/03/21' AND '2016/04/20'
Related
I have to perform a query on a MySQL database.
I have a table with records, have a column called "date" (the date type), and a column called "time" (type. Integer is stored by multiplying the time of day by 60. eg 8 am is stored as 480).
Unfortunately, the format of this table can not be modified.
My table stores attentions of doctors on call. The doctors on duty working in two shifts: from 8-20, and 20-8.
I need to know the amount of attention for every doctor.
My query must be filtered by date range and shift.
The problem is that, in the case of doctors working at the turn of 20-8, I have to consider a change of day. (sorry for my bad English).
What I have done is this, this would be an example to date of yesterday, and doctors shift 20-8.
SELECT * FROM attentions WHERE (date >= '2015-07-23' and time >=1200) and (date <= '2015-07-24' and time <480)
the query does not work at all.
Supposing the date field is called: 'a_date' with format 'yyyy-mm-ss' and the time field is a number, the query should be:
SELECT * FROM attentions WHERE (date(a_date) >= '2015-07-23' and time >=1200) and (date(a_date) <= '2015-07-24' and time <480)
Can you check using between?
SELECT * FROM attentions WHERE date between '2015-07-23' and '2015-07-24' and time between 1200 and 480
I think you can also use this -
SELECT * FROM ***** where CREATED_DATETIME between '2015-03-12 00:00:00' and '2015-05-11 00:00:00';
I have a field of FromDate and a field of ToDate.
I am looking for the rows that today is between the "from" and "to"
select * from job
where job.type='manager'
and '2014-01-22' between job.FromDate and job.ToDate
The query does not throw an exception , and it even returns some rows. But it isn't right- the rows it returns do not have the dates I am looking for.
P.S. the date format I am using is the correct one for my DB.
Try this
select * from job
where job.type='manager'
and job.FromDate <= '2014-01-22' and job.ToDate >= '2014-01-22'
Comparing dates is often tricky, especially if the values are stored as datetime and not date. The time components can affect the comparison. Another possibility is that ToDate is NULL for the most recent records. Here is one way to fix this:
select *
from job
where job.type ='manager' and
date('2014-01-22') between date(job.FromDate) and date(coalesce(job.ToDate, '2099-12-31'))
However, the use of the function on the columns can make the query less efficient. Instead, you might try:
select *
from job
where job.type ='manager' and
job.FromDate < '2014-01-23' and
(job.ToDate >= '2014-01-22' or job.ToDate is null);
I generally use datetime field to store created_time updated time of data within an application.
But now i have come across a database table where they have kept date and time separate fields in table.
So what are the schema in which two of these should be used and why?
What are pros and cons attached with using of two?
There is a huge difference in performance when using DATE field above DATETIME field. I have a table with more then 4.000.000 records and for testing purposes I added 2 fields with both their own index. One using DATETIME and the other field using DATE.
I disabled MySQL query cache to be able to test properly and looped over the same query for 1000x:
SELECT * FROM `logs` WHERE `dt` BETWEEN '2015-04-01' AND '2015-05-01' LIMIT 10000,10;
DATETIME INDEX:
197.564 seconds.
SELECT * FROM `logs` WHERE `d` BETWEEN '2015-04-01' AND '2015-05-01' LIMIT 10000,10;
DATE INDEX:
107.577 seconds.
Using a date indexed field has a performance improvement of: 45.55%!!
So I would say if you are expecting a lot of data in your table please consider in separating the date from the time with their own index.
I tend to think there are basically no advantages to storing the date and time in separate fields. MySQL offers very convenient functions for extracting the date and time parts of a datetime value.
Okay. There can be some efficiency reasons. In MySQL, you can put separate indexes on the fields. So, if you want to search for particular times, for instance, then a query that counts by hours of the day (for instance) can use an index on the time field. An index on a datetime field would not be used in this case. A separate date field might make it easier to write a query that will use the date index, but, strictly speaking, a datetime should also work.
The one time where I've seen dates and times stored separately is in a trading system. In this case, the trade has a valuation date. The valuation time is something like "NY Open" or "London Close" -- this is not a real time value. It is a description of the time of day used for valuation.
The tricky part is when you have to do date arithmetic on a time value and you do not want a date portion coming into the mix. Ex:
myapptdate = 2014-01-02 09:00:00
Select such and such where myapptdate between 2014-01-02 07:00:00 and 2014-01-02 13:00:00
1900-01-02 07:00:00
2014-01-02 07:00:00
One difference I found is using BETWEEN for dates with non-zero time.
Imagine a search with "between dates" filter. Standard user's expectation is it will return records from the end day as well, so using DATETIME you have to always add an extra day for the BETWEEN to work as expected, while using DATE you only pass what user entered, with no extra logic needed.
So query
SELECT * FROM mytable WHERE mydate BETWEEN '2020-06-24' AND '2020-06-25'
will return a record for 2020-06-25 16:30:00, while query:
SELECT * FROM mytable WHERE mydatetime BETWEEN '2020-06-24' AND '2020-06-25'
won't - you'd have to add an extra day:
SELECT * FROM mytable WHERE mydatetime BETWEEN '2020-06-24' AND '2020-06-26'
But as victor diaz mentioned, doing datetime calculations with date+time would be a super inefficient nightmare and far worse, than just adding a day to the second datetime. Therefore I'd only use DATE if the time is irrelevant, or as a "cache" for speeding queries up for date lookups (see Elwin's answer).
i need to retreive data from database with the condition from date to to date using between query,
my query is,
select * from Master where Date between '01-08-2013' and '30-08-2013'
but it retreive all data from the table...
i need only data with in that date..
i tried another one like,
select * from PatientMaster where EntryDate >= '01-08-2013' and EntryDate<= '30-08-2013'
how its posible..
whats wrong with my query...
sorry im very bad in english...
thank you in advance...
A date string has the syntax YYYY-MM-DD and not DD-MM-YYYY
select * from Master
where `Date` between '2013-08-01' and '2013-08-30'
for that you can use
select * from Master where Date >='01-08-2013' and dateadd(dd,1,'30-08-2013')
You have to convert your strings to dates. This page shows you how to do it in mysql, which is what you have tagged. For sql server, which is in your subject line, use this page.
Then you do a slight modification of your 2nd attempt. Instead of
and EntryDate <= the end date
you want
and EntryDate < the day after the end date
That takes care of any time components. It might not matter in your case, but it's a good habit to get into.
You'll be looking for an query that works with your format? (dd-mm-yy)
CAST to the desired format!
http://www.w3schools.com/sql/func_convert.asp
105 = dd-mm-yy
SELECT * FROM Master
WHERE CONVERT(date, Date, 105) BETWEEN '01-08-13' and '30-08-13'
Be conscious with regards of the choice of data type for date Columns,
with or without time, day or year first etc. and please do not use varchar
for dates...
know that it CAN be confusing to call a date column for only Date...
be consistent with high/lower case.
If I have MySQL query like this, summing word frequencies per week:
SELECT
SUM(`city`),
SUM(`officers`),
SUM(`uk`),
SUM(`wednesday`),
DATE_FORMAT(`dateTime`, '%d/%m/%Y')
FROM myTable
WHERE dateTime BETWEEN '2011-09-28 18:00:00' AND '2011-10-29 18:59:00'
GROUP BY WEEK(dateTime)
The results given by MySQL take the first value of column dateTime, in this case 28/09/2011 which happens to be a Saturday.
Is it possible to adjust the query in MySQL to show the date upon which the week commences, even if there is no data available, so that for the above, 2011-09-28 would be replaced with 2011/09/26 instead? That is, the date of the start of the week, being a Monday. Or would it be better to adjust the dates programmatically after the query has run?
The dateTime column is in format 2011/10/02 12:05:00
It is possible to do it in SQL but it would be better to do it in your program code as it would be more efficient and easier. Also, while MySQL accepts your query, it doesn't quite make sense - you have DATE_FORMAT(dateTime, '%d/%m/%Y') in select's field list while you group by WEEK(dateTime). This means that the DB engine has to select random date from current group (week) for each row. Ie consider you have records for 27.09.2011, 28.09.2011 and 29.09.2011 - they all fall onto same week, so in the final resultset only one row is generated for those three records. Now which date out of those three should be picked for the DATE_FORMAT() call? Answer would be somewhat simpler if there is ORDER BY in the query but it still doesn't quite make sense to use fields/expressions in the field list which aren't in GROUP BY or which aren't aggregates. You should really return the week number in the select list (instead of DATE_FORMAT call) and then in your code calculate the start and end dates from it.