fixing dbtimestamp conversion mistake - sql

I am using ssis to convert a dd-mm-yyyy varchar input into a dbtimestamp field, using the data conversion transformation. My mistake was that the conversion produces a yyyy-mm-dd where mm is the dd from the input and the dd is the mm. So if i have an input 04-01-2019 00:00:000 it produces 2019-04-01 00:00:000.
my solution is to use substrings to transform the input into standard iso format YYYY-MM_dd first and then convert to datetime data type. My problem is how am i going to correct the existing records (move dd to mm and mm to dd)? Probably substrings again?

Assuming your table only has incorrectly implicitly cast values (like '04-01-2019' (dd-MM-yyyy) to 20190401) and none which haven't been, you could use CONVERT and some style codes:
SELECT D,
CONVERT(date,CONVERT(varchar(10),V.D,101),103)
FROM (VALUES(CONVERT(date,'20190401'))) V(D);
As an UPDATE statement, that would be:
UPDATE YourTable
SET YourDateColumn = CONVERT(date,CONVERT(varchar(10),YourDateColumn ,101),103);
This converts the date back into a varchar with the format MM/dd/yyyy, and converts it back to a date but treats the value as dd/MM/yyyy (thus switching the day and month).

Related

SQL - Date format conversion issue (AUTO to 'MM/DD/YYYY')

In Snowflake, I have a column in a created table called "Date1", that has dates formatted as AUTO (ex. 2022-06-17). I am trying to query that column, but need the date formatted as 'MM/DD/YYYY', yet everything I've tried returns an error of some kind.
When I try date(Date1, 'MM/DD/YYYY) the error says that it can't parse 2022-06-17 for MM/DD/YYYY. When I try to_date(Date1 [MM/DD/YYYY]) or try_to_date(Date1 [MM/DD/YYYY]) the error says it doesn't recognize MM.
Any thoughts?
If you're trying to display the date using a specific format, you're converting to a varchar rather than a date:
select to_varchar(current_date, 'MM/DD/YYYY');
If you're trying to compare a column with a date to a formatted string in MM/DD/YYYY format then:
select current_date = try_to_date('08/04/2022', 'MM/DD/YYYY');
You should try to provide correct format to match 2022-06-17 literal:
SELECT TRY_TO_DATE(Date1, 'YYYY-MM-DD')
FROM tab_name;
Your column is already of type DATE. TO_DATE() and TRY_TO_DATE() convert non-date formats (string, integer) to a DATE type. They are not a means to format your DATE for presentation.
Date data type and presentation format are indepent.
You can alter your session to change the default display format of a date, but the underlying representation in the database remains the same.
alter session set DATE_INPUT_FORMAT='MM/DD/YYYY';
alter session set DATE_OUTPUT_FORMAT='MM/DD/YYYY';
select <col_name> from table; -- Now will show as MM/DD/YYYY for date columns

Why procedure throws error if I pass it date i.e. 20/04/2020?

I am using this
CAST(NotifDate as date) between #FromNotifDate AND #ToNotifDate
but NotifDate is saved as varchar in table but FromNotifDate AND ToNotifDate are of Date type.
When I pass these parameters 08/06/2014 and 20/04/2020 09:40:17 it doesn't work and throws error i.e.
Conversion failed when converting date and/or time from character string.
but if I pass 08/06/2014 and 10/04/2020 09:40:17 it works.
Your current database locale settings are probably set to en-US or another where the date format is MM/dd/yyyy.
That makes 08/06/2014 and 10/04/2014 valid dates (but they are 6th of August and 4th of October, not 8th of June and 10th of April!), but not 20/04/2020.
To use a different date format, you can use CONVERT, with the proper style code (I believe it's 103 for dd/MM/yyyy (see documentation)
So, this should work for you : CONVERT(date, NotifDate, 103)
Note that, as a general recommendation, it would be beneficial that you input NotifDate as a proper SQL Date in your DB in the first place, if possible, to avoid having to do conversion like this in your queries.
Also, there the unambiguous and international standard ISO-8601 format yyyy-MM-dd which should be always parsed correctly by CAST, I recommend using it over any localized format where you can in your code infrastructure.
System having default date format is "MM/dd/yyyy" so while you set "10/04/2020 09:40:17" value so system throm an Error- out of range Error,
-- The conversion of a varchar data type
-- to a datetime data type resulted in an out-of-range value.
select cast('20/04/2020 09:40:17' as datetime)
-- get the current session date_format
select date_format
from sys.dm_exec_sessions
where session_id = ##spid
-- set the dateformat for the current session
set dateformat dmy
-- this should work
select cast('20/04/2020 09:40:17' as datetime)

Why does SQL Server convert VARCHAR to DATETIME using an invalid style?

I can't make out from the documentation why SQL Server parses a text in a format other than the specified style.
Regardless of whether I provide text in the expected format:
SELECT CONVERT(DATETIME, N'20150601', 112)
or incorrect format (for style 113):
SELECT CONVERT(DATETIME, N'20150601', 113)
The results are the same: 2015-06-01 00:00:00.000 I would expect the latter to fail to convert the date (correctly).
What rules does it employ when trying to convert a VARCHAR to DATETIME? I.e. why does the latter (incorrect format style) still correctly parse the date?
EDIT: It seems I've not been clear enough. Style 113 should expect dd mon yyyy hh:mi:ss:mmm(24h) but it happily converts values in the format yyyymmdd for some reason.
Because the date is in a canonical format ie(20150101). The database engine falls over it implicitly. This is a compatibility feature.
If you swapped these around to UK or US date formats, you would receive conversion errors, because they cannot be implicitly converted.
EDIT: You could actually tell it to convert it to a pig, and it would still implicitly convert it to date time:
select convert(datetime,'20150425',99999999)
select convert(datetime,'20150425',100)
select convert(datetime,'20150425',113)
select convert(datetime,'20150425',010)
select convert(datetime,'20150425',8008135)
select convert(datetime,'20150425',000)
And proof of concept that this is a compatibility feature:
select convert(datetime2,'20150425',99999999)
Although you can still implicitly convert datetime2 objects, but the style must be in the scope of the conversion chart.
Reason why is the date N'20150601' converted to valid datetime is because of fact that literal N'20150601' is universal notation of datetime in SQL Server. That means, if you state datetime value in format N'yyyymmdd', SQL Server know that it is universal datetime format and know how to read it, in which order.
You should convert to varchar type in order to apply those formats:
SELECT CONVERT(varchar(100), CAST('20150601' as date), 113)
OK, you are converting datetime to datetime. What did you expect? In order to apply formats you should convert to varchar and you have to have date or time type as second parameter.

Converting Date format in Sql Server

I have a column in my table for storing dates and it is in 12-06-2013 15:32:45. I want to convert it to MM/DD/YYYY format. How can I do it?
Coulmn type is varchar
First you need to CONVERT VARCHAR() to datetime type and and then to CONVERT it to string in desired format:
SELECT CONVERT (varchar (10), CONVERT (date,'12-06-2013 15:32:45' ,103),101)
First 103 is used to interpret current date format, and second - 101 - target format.
If you change target date format from varchar to date then your output in MSMS will be in default display date format of you SQL Server, not the desired format. This is because SQL Server stores dates as integers and converts them before dispalying the value. Therefore if you need to store in certain format, then store in VARCHAR type.
Check out CAST and CONVERT functions on MDSN
or you can do it in your c# code like that :
First you have to take your date from your table and put it in string var "DT" exemple :
string strDT =db.TableTitle.date;
string date = strDT .ToString("MM/DD/YYYY");
DateTime DT = Convert.ToDateTime(date);
then you can use the DT time variable :)

Convert Date Against Where Clause

I have Following dummy table with data:
ACID srno date(mm/dd/yyyy) name
3 1 04/12/2010 mahesh
3 2 04/12/2010 mahendra
Now if I try with Following SQL Transact:
select srno from dummy
where name = 'mahesh'
and date= convert(datetime,'12/04/2010',101) –- I have date in dd/MM/yyyy Format
and ACID=3
It’s Not returning the srno of the table. That means Date is not execute convert statement as above
What’s the reason?
Try using style 103 instead of 101.
select srno from dummy
where name = 'mahesh'
and date= convert(datetime,'12/04/2010',103) –- I have date in dd/MM/yyyy Format
and ACID=3
If you convert 12/04/2010 using format 101, you get date "December 4, 2010", which is not in your database. Use format 103 to convert a date in format dd/mm/yyyy to DateTime.
The database stores dates using the DateTime type which is format-agnostic. It does have a default format for string conversions, which seems to be mm/dd/yyyy (101) on your database.
However, when you convert a string to add it to your table, you want to specify the format of your input string, in your example dd/mm/yyyy (103).
Take a look at the MSDN article for CAST and CONVERT which details all format styles that you can use with dates.
To be honest, if you want to specify a DATE LITERAL in SQL Server, please stick with the simplest YYYYMMDD format, e.g.
and dummy.date = '20100412'
It is robust and works for all regional, user language and dateformat settings. This assumes the other side of the comparison is already a date column. Even if you had to CAST it, using this format you don't need to specify a format
and dummy.date = cast('20100412' as datetime)