Is there a way to write a query equivalent to
select * from log_table where dt >= 'nov-27-2009' and dt < 'nov-28-2009';
but where you could specify only 1 date and say you want the results for that entire day until the next one.
I'm just making this up, but something of the form:
select * from log_table where dt = 'nov-27-2009':+1;
I do not believe there is one method that is portable to all RDBMSes.
A check in one of my references (SQL Cookbook) shows that no one RDBMS solves the problem quite the same way. I would recommend checking out Chapter 8 of that book, which covers all of the different methods for DB2, Oracle, PostgreSQL, MySQL.
I've had to deal with this issue in SQLite, though, and SQL Cookbook doesn't address that RDBMS, so I'll mention a bit about it here. SQLite doesn't have a date/time data type; you have to create your own by storing all date/time data as TEXT and ensure that your application enforces its formatting. SQLite does have a set of date/time conversion functions that allow you to add nominal date/times while maintaining the data as strings. If you need to add two time durations (HH:MM:SS) to each other, though, based upon data that you've stored in text columns that you are treating as date/time data, you'll have to write your own functions (search for "Defining SQLite User Functions") and attach them to the database at runtime via a call to sqlite3_create_function(). If you want an example of some user functions that add time values, let me know.
For MS SQL Server, check out DATEPART.
/* dy = Day of Year */
select * from log_table where datepart(dy, dt) = datepart(dy, '2009-nov-27');
With SQL Server, you could
Select * From table
Where dt >= DateAdd(day, DateDiff(day, 0, #ParamDate), 0)
And dt < DateAdd(day, DateDiff(day, 0, #ParamDate), 1)
As long as you are dealing with the date data type for the respective data type, the following will work:
t.date_column + 1
...will add one day to the given date. But I have yet to find a db that allows for implicit data type conversion into a date.
SELECT '12-10-2009' + 1
...will fail on SQL Server because SQL Server only performs the implicit conversion when comparing to a datetime data type column. So you need to use:
SELECT CONVERT(DATETIME, '12-10-2009') + 1
For Oracle, you'd have to use the TO_DATE function; MySQL would use something like STR_TO_DATE, etc.
Have a column that just has the date part (time is 00:00:00.000) and then you can add a where clause: WHERE dt = '2009-11-27'
Related
I have a Sql server table which contains below Date values(4th october)
Now Below query is not showing any result
select
*
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '10/01/2018' and TBA.ActionDate <= '10/04/2018' which is not correct.
But If I write
select
*
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '10/01/2018' and TBA.ActionDate <= '10/05/2018' it is returning me all results.
What I am doing wrong.
There are two problems with this query. The first, is that it's using a localized string. To me, it looks like it's asking for rows between January and April. The unambiguous date format is YYYYMMDD. YYYY-MM-DD by itself may not work in SQL server as it's still affected by the language. The ODBC date literal, {d'YYYY-MM-DD'} also works unambiguously.
Second, the date parameters have no time which defaults to 00:00. The stored dates though have a time element which means they are outside the search range, even if the date parameter was recognized.
The query should change to :
select
*
from [dbo].[TB_AUDIT] TBA
where
cast(TBA.ActionDate as date) between '20181001' and '20181004'
or
cast(TBA.ActionDate as date) between {d'2018-10-01'} and {d'2018-10-04'}
Normally, applying a function to a field prevents the server from using any indexes. SQL Server is smart enough though to convert this to a query that covers the entire date, essentially similar to
where
TBA.ActionDate >='2018:10:01T00:00' and TBA.ActionDate <'2018-10-05T00:00:00'
When you don't specify a time component for a DATETIME, SQL Server defaults it to midnight. So in your first query, you're asking for all results <='2018-10-04T00:00:00.000'. All of the data points in your table are greater than '2018-10-04T00:00:00.000', so nothing is returned.
You want
TBA.ActionDate >= '2018-10-01T00:00:00.000' and TBA.ActionDate < '2018-10-05T00:00:00.000'`
Use properly formatted dates!
select *
from [dbo].[TB_AUDIT] TBA
where TBA.ActionDate >= '2018-10-01' and TBA.ActionDate <= '2018-10-04'
YYYY-MM-DD isn't just a good idea. It is the ISO standard for date formats, recognized by most databases.
when you just filter by the date, it is with regard to the time as per the standard.
I have a SQL query which shows time activity of each account. Database is Microsoft SQL Server on Windows Server 2008.
Help me please to translate this query to tableau with using parameters Parameters.Date1 and Parameters.Date2 instead of #time.
The result of the query:
USER,Date,Total time
USER1,2016-09-22,07:00:00.0000000
USER2,2016-09-22,08:00:00.0000000
USER3,2016-09-22,05:00:00.0000000
SQL query:
DECLARE #time datetime
set #time = '08.09.2016'
SELECT
[User],
CAST(DATEADD(SECOND, sum(datediff(DAY, #time, [Start])), #time) AS date) 'Date',
CAST(DATEADD(SECOND, sum(datediff(SECOND, '00:00:00',[Period])), '00:00:00') AS time) 'Total time'
FROM
[User].[dbo].[UserAction]
WHERE
[Start] >= #time+'00:00:00' and [Start] <= #time+'23:59:59'
GROUP BY
[USER]
input data to build the query:
USER, Start,End,Period
USER1,2016-09-22 09:00:00.000,2016-09-22 12:00:00.000,03:00:00
USER1,2016-09-22 12:00:00.000,2016-09-22 13:00:00.000,01:00:00
USER1,2016-09-22,13:00:00.000,2016-09-22 16:00:00.000,03:00:00
USER2,2016-09-22,09:00:00.000,2016-09-22 13:00:00.000,04:00:00
USER2,2016-09-22,13:00:00.000,2016-09-22 17:00:00.000,04:00:00
USER3,2016-09-22,09:00:00.000,2016-09-22 10:00:00.000,01:00:00
USER3,2016-09-22,10:00:00.000,2016-09-22 12:00:00.000,02:00:00
USER3,2016-09-22,12:00:00.000,2016-09-22 14:00:00.000,02:00:00
I don't have enough imaginary stack overflow points yet to make a comment instead of an answer, but I would agree with Gordon Linoff.
A table valued function in sql can be used directly in a Tableau data source, and it's treated just like a table.
Note I did not test the below, but here is what the equivalent function might look like:
CREATE FUNCTION dbo.MyFuntion (#time datetime)
RETURNS TABLE
AS
RETURN
(
SELECT
[User]
,cast(DATEADD(SECOND, sum(datediff(DAY, #time,[Start])),#time) as date)'Date'
,cast(DATEADD(SECOND, sum(datediff(SECOND, '00:00:00',[Period])),'00:00:00') as time)'Total time'
FROM
[User].[dbo].[UserAction]
WHERE
[Start] >= #time+'00:00:00' and [Start] <= #time+'23:59:59'
GROUP BY [USER]
);
Tableau 9 (haven't tried 10) seems to discourage custom SQL (it warns anyone that opens your workbook) and stored procedures (slow vs. same sql in a function).
Alternatively, adding the pure dbo.UserAction table to a data source and making calculated fields for the second two columns might work: Tableau Documentation. It seems to have all the functions needed to manipulate dates. However, there may be some crazy limitation associated with parameters that might limit it, honestly can't remember off the top of my head.
You don't need custom SQL for this. Keep it simple. Connect Tableau directly to your UserAction table.
You can either:
Put Day(Start) on the filter shelf, Make sure it is a continuous Date truncated to the Day. Show the filter and set the filter to let you pick a single value at a time - I would choose a slider UI.
Or write a calculated field to put on the filters shelf that references a parameter such as day(Start) = day(Date1)
Put User on one shelf, such as rows, and Sum(Period) on another such as columns. That should do it unless Tableau has trouble interpreting your Period field datatype. If so, try changing the datatype to Number inside Tableau to see if it converts durations to numbers automatically, if not you may need to write a calculated field for the conversion.
There is this strange error in sql query.
The query is something like this.
select * from student where dob between '20150820' and '20150828'
But in the database the column of dob is varchar(14) and is in yyyyMMddhhmmss format,Say my data in the row is (20150827142545).If i fire the above query it should not retrive any rows as i have mentioned yyyyMMdd format in the query.But it retrives the row with yesterday date (i.e 20150827112535) and it cannot get the records with today's date (i.e 20150828144532)
Why is this happening??
Thanks for the help in advance
You can try like this:
select * from student
where convert(date,LEFT(dob,8)) between
convert(date'20150820') and convert(date,'20150828'))
Also as others have commented you need to store your date as Date instead of varchar to avoid such problems in future.
As already mentioned you would need to use the correct date type to have between behave properly.
select *
from student
where convert(date,LEFT(dob,8)) between '20150820' and '20150828'
Sidenote: You don't have to explicitly convert your two dates from text as this will be done implicitly as long as you use an unambiguous date representation, i.e. the ISO standard 'YYYYMMDD' or 'YYYY-MM-DD'. Of course if you're holding the values in variables then use date | datetime datatype
declare #startdate date
declare #enddate date
select *
from student
where convert(date,LEFT(dob,8)) between #startdate and #enddate
Sidenote 2: Performing the functions on your table dob column would prevent any indexes on that column from being used to their full potential in your execution plan and may result in slower execution, if you can, define the correct data type for the table dob column or use a persistent computed column or materialised view if your performance is a real issue.
Sidenote 3: If you need to maintain the time portion in your data i.e. date and time of birth, use the following to ensure all records are captured;
select *
from student
where
convert(date,LEFT(dob,8)) >= '20150820'
and convert(date,LEFT(dob,8)) < dateadd(d,1,'20150828')
All you have to do is to convert first the string to date.
select *
from student
where dob between convert(date, '20150820') and convert(date, '20150828')
Why is this happening?
The comparison is executed from left to right and the order of characters is determined by the codepage in use.
Sort Order
Sort order specifies the way that data values are sorted, affecting
the results of data comparison. The sorting of data is accomplished
through collations, and it can be optimized using indexes.
https://msdn.microsoft.com/en-us/library/ms143726.aspx
There are problems with between in T-SQL.
But if you want a fast answer convert to date first and use >= <= or even datediff to compare - maybe write a between function yourself if you want the easy use like between and no care about begin and start times ...
What do BETWEEN and the devil have in common?
I am importing records from a DB2 data source into a MS SQL Server destination.
The records are coming in with the date format of 20150302/YYYYMMDD, but I only want the last 14 days based on current server date.
Can some advise on how to select based on this date format against DATEADD(d, - 1, { fn CURDATE() }) please.
Thanks!
It would be better to do this on the DB2 side, to reduce the number of records brought over.
Additionally, it's better from a performance standpoint to convert the static date into a numeric date and compare to the column in your table. Rather than convert the numeric date in your table to a actual date type for comparison.
where numdate >= int(replace(char(current_date - 14 days,iso),'-',''))
Doing it this way will allow you to take advantage of an index over numdate. In addition, DB2 will only need to perform this conversion once.
Depending on your platform & version, you may have an easier way to convert from a date data type to a numeric date. But the above works on DB2 for i and should work on most (all?) DB2 versions and platforms.
You may find it worthwhile to create a UDF to do this conversion for you.
If you want logic in SQL Server, then you are in luck, because you can just convert the YYYYMMDD format to a date:
where cast(datecol as date) >= cast(getdate() - 14 as date)
(This assumes no future dates.)
If you want to do this on the DB2 side, you can use to_date():
where to_date(datecol, 'YYYYMMDD') >= current date - 14 days
I've been tasked to take a calendar date range value from a form front-end and use it to, among other things, feed a query in a Teradata table that does not have a datetime column. Instead the date is aggregated from two varchar columns: one for year (CY = current year, LY = last year, LY-1, etc), and one for the date with format MonDD (like Jan13, Dec08, etc).
I'm using Coldfusion for the form and result page, so I have the ability to dynamically create the query, but I can't think of a good way to do it for all possible cases. Any ideas? Even year differences aside, I can't think of anything outside of a direct comparison on each day in the range with a potential ton of separate OR statements in the query. I'm light on SQL knowledge - maybe there's a better way to script it in the SQL itself using some sort of conversion on the two varchar columns to form an actual date range where date comparisons could then be made?
Here is some SQL that will take the VARCHAR date value and perform some basic manipulations on it to get you started:
SELECT CAST(CAST('Jan18'||TRIM(EXTRACT(YEAR FROM CURRENT_DATE)) AS CHAR(9)) AS DATE FORMAT 'MMMDDYYYY') AS BaseDate_
, CASE WHEN Col1 = 'CY'
THEN BaseDate_
WHEN Col1 = 'LY'
THEN ADD_MONTHS(BaseDate_, -12)
WHEN Col1 = 'LY-1'
THEN ADD_MONTHS(BaseDate_, -24)
ELSE BaseDate_
END AS DateModified_
FROM {MyDB}.{MyTable};
The EXTRACT() function allows you to take apart a DATE, TIME, or TIMESTAMP value.
You have you use TRIM() around the EXTRACT to get rid of the whitespace that is added converting the DATEPART to a CHAR data type. Teradata is funny with dates and often requires a double CAST() to get things sorted out.
The CASE statement simply takes the encoded values you suggested will be used and uses the ADD_MONTHS() function to manipulate the date. Dates are INTEGER in Teradata so you can also add INTEGER values to them to move the date by a whole day. Unlike Oracle, you can't add fractional values to manipulate the TIME portion of a TIMESTAMP. DATE != TIMESTAMP in Teradata.
Rob gave you an sql approach. Alternatively you can use ColdFusion to generate values for the columns you have. Something like this might work.
sampleDate = CreateDate(2010,4,12); // this simulates user input
if (year(sampleDate) is year(now())
col1Value = 'CY';
else if (year(now()) - year(sampleDate) is 1)
col1Value = 'LY'
else
col1Value = 'LY-' & DateDiff("yyyy", sampleDate, now());
col2Value = DateFormat(sampleDate, 'mmmdd');
Then you send col1Value and col2Value to your query as parameters.