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

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

Related

I have an oracle table which has date in dd-mm-yyyy and dd/mm/yyyy format in same field. Now i have to convert into one common format

I have an oracle table which has date in dd-mm-yyyy and dd/mm/yyyy format in same field. Now i have to convert into one common format.
Please suggest how to approach this?
I did tried but it is failing as it is failing due to invalid month.
Is there a way i can first identify what format the date is and then based on case statement i might convert.
or something easy way? Please
I trust you've learnt your lesson and you're now going to store these dates in the date data type.
Your two different date formats actually aren't important, Oracle already is a little over accepting when it comes to separating characters.
e.g
to_date('01/01/1900','dd-mm-yyyy')
Does not error
I did tried but it is failing as it is failing due to invalid month.
Your error is coming because you've allowed a value that doesn't match either of those formats into your string column.
If you are on version 12.2 at least (which you should be in 2020) then you can use the validate_conversion function to identify rows that don't convert to a date with your format (https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sqlrf/VALIDATE_CONVERSION.html#GUID-DC485EEB-CB6D-42EF-97AA-4487884CB2CD)
select string_column
from my_table
where validate_conversion(string_column AS DATE,'dd/mm/yyyy') = 0
The other additional helper we got in 12.2 was the on conversion error clause of to_date. So you can do.
alter table my_table add my_date date;
update my_table set my_date = to_date(my_string default null on conversion error,'dd/mm/yyyy');
If you are confident that there is no other format than those two, a simple approach is replace():
update mytable set mystring = replace(mystring, '/', '-');
This turns all dates to format dd-mm-yyyy.
I would suggest taking a step forward and convert these strings to a date column.
alter table mytable add mydate date;
update mytable set mydate = to_date(replace(mystring, '/', '-'), 'dd-mm-yyyy');
This will fail if invalid date strings are met. I tend to consider that a good thing, since it clearly signals that this a problem with the data. If you want to avoid that, you can use on conversion error, available starting Oracle 12:
to_date(
replace(mystring, '/', '-') default null on conversion error,
'dd-mm-yyyy'
)
Then you can remove the string column, which is no longer needed.

Converting records from 'YYYY-MM-DD' format to MM/DD/YYYY in PL/SQL

I am trying to convert a specified column which is in format 'YYYY-MM-DD' and I need to convert it in MM/DD/YYYY as a data warehousing task.
The specified column is in varchar2 format.
I've been trying to use to_date, to_char but haven't succeeded yet. Any ideas?
We can try first converting your text dates into bona fide dates using TO_DATE. Then, we can use TO_CHAR to convert them to the new format.
UPDATE yourTable
SET date_col = TO_CHAR(TO_DATE(date_col, 'YYYY-MM-DD'), 'MM/DD/YYYY');
-- and maybe a WHERE clause
This being said, it is bad practice to persist your date information as text. Rather, use a proper date or timestamp column if at all possible. You would be better off creating a new date column, and then stopping after calling TO_DATE.
Inside your function/procedure, you can try this:
some_var := to_char(to_date(column_to_convert,'YYYY-MM-DD'),'MM/DD/YYYY');
It converts first the data to a date, then back to varchar2 using the desired format. Just replace the identifiers accordingly.
this will work:
select to_char(to_date('2018-10-19','YYYY-MM-DD'),'MM/DD/YYYY')from dual;

To get all the dates in a format dd/mm/yyyy. I have a date field in the format yyyymmdd

In my DB, there is a date field in the format yyyymmdd.
I have to get all the dates in the format dd-mm-yyyy for that particlar date.
ex:
Date
20170130
20170228
20170325
for the above dates, I need the output in the below format with the dates and day of the particular dates
date day
30-01-2017 tuesday
28-02-2017 tuesday
25-03-2017 saturday
If the column is a string, then it can hold invalid date values such as February 31, one way to avoid this is by a small function such as this:
create or replace
function my_to_date( p_str in varchar2 ) return date
is
begin
return to_date( p_str );
exception
when others then
return null;
end;
\\
select to_char(my_to_date('20170231'),'DD-MM-YYYY Day')
from dual
\\
Demo
Try below:
Select to_char(yrdate, 'dd-mm-yyyy'), to_char(yrdate, 'D') from yrtable
It sounds like your dates aren't actually DATE fields but some kind of CHAR field? The best option would be to convert to DATE and then convert back to CHAR:
SELECT TO_CHAR(TO_DATE(mydate, 'YYYYMMDD'), 'DD-MM-YYYY Day')
FROM mytable;
This uses the YYYYMMDD mask to convert your string into a date, then uses the mask DD-MM-YYYY Day to convert it back into a string. Use day if you want the day name in lowercase (as in your OP).
#user2778168 answer will give you the results you want. But why?
Your database does not have dates stored in yyyymmdd format or any other date format for at mater, unless it's defined with a character type definition. Oracle stores all dates in a single internal structure, and with only slight variations timestamps are the same. The format used only tells Oracle how to display the value or to convert a string to a date. Unless a specific format is specified Oracle uses the NLS_DATE_FORMAT for this determination. See here and scan down to "Datetime Format Models" for format specifications.
To see this run the following:
select value
from nls_session_parameters
where parameter = 'NLS_DATE_FORMAT';
Select yrdate default_format
, to_char(yrdate, 'dd-mm-yyyy') specified_format
, dump(yrdate) unformated
from yrtable;
alter session set nls_date_format = 'Month dd,yyyy';
Rerun the above queries.
It seems you hold date column(date1) in character format. Suppose you have a table named days:
SQL> desc days
date1 varchar2(10)
then,
we should convert it into date, and then into char format, with aliases in quotation marks to provide lowercase aliases as you wanted.
perhaps your database's date language is non-english like mine(turkish), then you need to convert it to english.
lastly, it'a appropriate to order the results according to converted date, seen from your output. So we can use the following SQL :
select to_char(to_date(date1,'yyyymmdd'),'dd-mm-yyyy') "date",
to_char(to_date(date1,'yyyymmdd'),'day','nls_date_language=english') "day"
from days
order by to_date(date1,'yyyymmdd');
D e m o

Convert Data from yyyy-dd-mm to mm/dd/yyyy Issue

I have a column in my table with Dates in the format yyyy-mm-dd I want to convert all the dates in that column to the format mm/dd/yyyy
I am using the below query
UPDATE Test.dbo.Status
SET DateIn = CONVERT(DATE,DateIn ,101)
The DateIn column is defined as Date in my table (DateIn DATE NULL)
The query does no change to the data. am I doing some thing wrong here?
You can change the default format in which SQL Server displays a date, but you can't alter the way a DATE value is stored via CONVERT(). You can format a date however you want if you store it as a string, but you lose functionality when you do that and it's not advisable. If you are hell-bent on storing a formatted version, you might want to create a new VARCHAR() field so you can preserve your DATE version.
You're better off formatting the date at the application level.
The reason your query does nothing is that the actual DATE values are equivalent. Notice when you take any valid date format and CAST() it as DATE the resulting format is the same regardless of the input:
SELECT CAST('20040510' AS DATE)
SELECT CAST('2004-05-10' AS DATE)
SELECT CAST('May 10, 2004' AS DATE)
All return: 2004-05-10 on my instance of SQL Server.

Ms Access - How to verify the date time format displayed in yyyy/mm/dd HH/MM/SS

May I know could I verify whether the date displayed in the field is in specific format
As per my requirement, the datetime should be displayed in format 'yyyy/mm/dd HH(24hr)/MM/SS'
Eg: The valid value should be '2014/07/18 14:16:48'. If the date is displayed as '18/07/2014 14:16:48', then it is invalid.
Using query how I verify whether it is shown in the format which I have expected. I could use IsDate option to verify it is a valid date and also I could use Mid function to verify the date separator which is '/', but how could I verify the format.
Thanks
If the column is stored as Text, use the SQL Like operator. Select valid dates:
SELECT * FROM myTable WHERE myDate Like "####/##/## ##:##:##"
Select invalid dates
SELECT * FROM myTable WHERE myDate Not Like "####/##/## ##:##:##"
# stands for a single digit.
See Like Operator.
But note that this only makes sense if myDate is a Text! If the type of myDate is Date/Time, the date is stored in a numeric format internally and is only formatted as a date for display. So don't confuse the date value per se and the date as it is displayed.
A Date/Time is always stored in the same way, no matter how it is formatted and displayed!
All you need to do is to open the Table in Design View and to set the Format property.