Converting decimal to Date - sql

I have a column with dates formatted as decimals, for example: 20,210,830.
I want to convert this number to date format as 08/30/2021
I have tried to use convert and the database shoots me an error that convert is not a valid function. Cast seems to work but, only returns a null value every time.
This statement will validate:
SELECT CAST(CAST(CONTCLMPDTE AS VARCHAR(8)) AS DATE)
FROM CMSFIL.JCTDSC AS COMPLDATE
This statement works but, just outputs null. For background I am querying from a Db2 database.
My ultimate goal is to use this converted date to grab the difference from the current day.
Such as
DAY(CURRENT_DATE) - DAY(COMPLDATE)

Converting it to a date, you cqan do it like this
CREATE TABLE JCTDSC (
CONTCLMPDTE varchar(10)
);
INSERT INTO JCTDSC VALUES ('20,220,830')
SELECT date(to_date(REPLACE(CONTCLMPDTE,',',''),'YYYYMMDD')) FROM JCTDSC AS COMPLDATE
1
2022-08-30
fiddle

So after a long couple days and almost pulling my hair out, here is what worked for me.
SELECT date(substr(CONTCLMPDTE,1,4)||'-'||substr(CONTCLMPDTE,5,2)||'-'||substr(CONTCLMPDTE,7,2)) FROM JCTDSC WHERE COMPANYNUMBER={Company Number} AND JOBNUMBER={Job Number} LIMIT 1
This formatted from yyyymmdd to mm/dd/yyyy. It also worked for finding the days between current_date and CONTCLMPDTE using this code.
DAYS(CURRENT_DATE) - DAYS({COntract Compl Date Formatted})
Thank you all for your help!

You probably get an error because you have some INT / DECIMAL value which can't be converted to a date using this pattern.
The solution is to create some "safe" conversion function "eating" errors like below.
CREATE FUNCTION DATE_SAFE (P_DT INT)
RETURNS DATE
CONTAINS SQL
NO EXTERNAL ACTION
DETERMINISTIC
BEGIN
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
RETURN CAST (NULL AS DATE);
END;
RETURN DATE (TO_DATE (CAST (P_DT AS CHAR (8)), 'YYYYMMDD'));
END
Usage:
SELECT
CONTCLMPDTE
--, DATE (TO_DATE (CAST (CONTCLMPDTE AS CHAR (8)), 'YYYYMMDD'))
, DATE_SAFE (CONTCLMPDTE)
FROM (VALUES 0, 20220830) T (CONTCLMPDTE)
The function returns NULL if the corresponding INT can't be converted to a DATE, and no error is thrown as in case, when you uncomment the commented out line with built-in functions only.

The value just need to be converted into a string with a date format. Then you can use the date() function to convert to date.
create table qtemp/dec_vals (
col1 decimal(8,0) );
insert into qtemp/dec_vals
values (20200830), (20200831), (20200901), (20200902), (20200903), (20200904), (20200905), (20200906);
select date(substr(char(col1), 5, 2) || '/' || substr(char(col1), 7, 2) || '/' || substr(char(col1), 1, 4)) from qtemp/dec_vals;

Related

How to convert a NUMERIC field into a DATE field and use it in a WHERE clause in DB2?

I have a field that is integer format 20220801 that needs to be converted to a date field. I then need to use this field in a WHERE clause compared against the CURRENT DATE. This is specifically for DB2.
Every time I try to do this I receive this error message:
Here are some snippets I've tried unsuccessfully, each time returning the above error
SELECT
DATE(TIMESTAMP_FORMAT(CHAR(BWDUED), 'YYYYMMDD')) AS DUE_DATE,
CURRENT DATE AS TODAY_DATE
FROM
SCHEMA.TABLE
WHERE
DATE(TIMESTAMP_FORMAT(CHAR(BWDUED), 'YYYYMMDD')) = CURRENT_DATE
SELECT
DATE(TO_DATE(CHAR(BWDUED), 'YYYYMMDD')) AS DUE_DATE,
CURRENT DATE AS TODAY_DATE
FROM
SCHEMA.TABLE
WHERE
DATE(TO_DATE(CHAR(BWDUED), 'YYYYMMDD')) = CURRENT_DATE
I've looked at many of the answers on here, but none of them have gotten me past this error. Any help on navigating this would be appreciated!
Take a look at TIMESTAMP_FORMAT. It allows to specify the input format and you get a TIMESTAMP or DATE back.
VALUES (TIMESTAMP_FORMAT('20220801','YYYYMMDD'))
The problem is because some row contains a number which can't be formatted as a timestamp with the specified pattern.
Consider the following example returning exactly the same error, if you uncomment any of the commented out lines.
SELECT
DATE (TIMESTAMP_FORMAT (CHAR(BWDUED), 'YYYYMMDD')) AS DUE_DATE,
CURRENT DATE AS TODAY_DATE
FROM
(
VALUES
--0 ,
--20221232,
INT (TO_CHAR (CURRENT DATE, 'YYYYMMDD'))
) T (BWDUED)
WHERE
DATE (TIMESTAMP_FORMAT (CHAR(BWDUED), 'YYYYMMDD')) = CURRENT_DATE
The solution would be create a "safe" formatter function eating possible errors, and use it instead of TIMESTAMP_FORMAT (or synonym TO_DATE function).
CREATE OR REPLACE FUNCTION TO_DATE_SAFE
(
P_STR VARCHAR (128)
, P_FMT VARCHAR (128)
)
RETURNS TIMESTAMP
CONTAINS SQL
NO EXTERNAL ACTION
DETERMINISTIC
BEGIN
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
RETURN CAST (NULL AS TIMESTAMP);
END;
RETURN TO_DATE (P_STR, P_FMT);
END

Redshift can't convert a string to a date, tried multiple functions

I have a table with a field called ADATE, it is a VARCHAR(16) and the values are like so: 2019-10-22-09:00.
I am trying to convert this do a DATE type but cannot get this to work.
I have tried:
1
TO_DATE(ADATE, 'YYYY-MM-DD')
Can't cast database type date to string
2
TO_DATE(LEFT(ADATE, 10), 'YYYY-MM-DD')
Can't cast database type date to string
3
TO_DATE(TRUNC(ADATE), 'YYYY-MM-DD')
XX000: Invalid digit, Value '-', Pos 4, Type: Decimal
4
CAST(ADATE AS DATE)
Error converting text to date
5
CAST(LEFT(ADATE, 10) AS DATE)
Error converting text to date
6
CAST(TRUNC(ADATE) AS DATE)
Error converting numeric to date
The issue was the data containing blanks (not Nulls) so the error was around them.
I resolved this by using the following code:
TO_DATE(LEFT(CASE WHEN adate = '' THEN NULL ELSE adate END, 10), 'YYYY-MM-DD') adate
Clearly, you have bad date string values -- which is why the value should be stored as a date to begin with.
I don't think Redshift has a way of validating the date before attempting the comparison, or of avoiding an error. But you can use case and regular expressions to see if the value is reasonable. This might help:
(case when left(adate, 10) ~ '^(19|20)[0-9][0-9]-[0-1][0-9]-[0-3][0-9]$'
then to_date(left(adate, 10), 'YYYY-MM-DD')
end)
This is not precise . . . you can make it more complex so month 19 is not permitted (for instance), but it is likely to catch the errors.

storing date in 'CCYYMMDD' format in Teradata

I would like to store dates in the format CCYYMMDD in Teradata, but I fail to do so. Find below what I tried so far:
query 1:
SEL CAST(CAST(CURRENT_DATE AS DATE FORMAT 'YYYYMMDD') AS VARCHAR(8))
-- Output: 20191230 ==> this works!
query 2:
SEL CAST(CAST(CURRENT_DATE AS DATE FORMAT 'CCYYMMDD') AS VARCHAR(8))
-- output: SELECT Failed. [3530] Invalid FORMAT string 'CCYYMMDD'.
It seems that the CCYYMMDD is not available in Teradata right away. Is there a workaround?
Tool used: Teradata SQL assistant
Internally, dates are stored as integers in Teradata. So when you say you want to store them in a different format, I don't think you can do that. But you can choose how to display / return the values.
I'm sure there's a cleaner way to get the format you want, but here's one way:
WITH cte (mydate) AS (
SELECT CAST(CAST(CURRENT_DATE AS DATE FORMAT 'YYYYMMDD') AS CHAR(8)) AS mydate
)
SELECT
CAST(
(CAST(SUBSTRING(mydate FROM 1 FOR 2) AS INTEGER) + 1) -- generate "century" value
AS CHAR(2) -- cast value as string
) || SUBSTRING(mydate FROM 3) AS new_date -- add remaining portion of date string
FROM cte
SQL Fiddle - Postgres
You'd have to add some extra logic to handle years before 1000 and after 9999. I don't have a TD system to test, but give it a try and let me know.

Convert an Int to a date field

I'm trying to convert an integer field to an actual date field. Someone created a "date" field that just sticks in a "date" that is actually an integer. I'm trying to convert it to an actual date.
I have tried the following to no avail:
CAST(CAST(last_purch_date AS CHAR) AS DATE) as Create,
CAST( last_purch_date as datetime) as Created,
convert(datetime,last_purch_date) as Created1,
ISDATE(CONVERT(CHAR(8),last_purch_date)) as PleaseDearGodWORK
Simple cast as date could work
Select cast(cast(20161011 as varchar(8)) as date)
Returns
2016-10-11
If your data is suspect, you could also use Try_Convert()
Select Try_Convert(date,cast(2610 as varchar(8)))
Returns
NULL
SELECT convert(date,CONVERT(varchar(8),[columname],101))

All rows with date <= 90 days in oracle based on varchar2 date string [duplicate]

I have the following query that I am attempting to use as a COMMAND in a crystal report that I am working on.
SELECT * FROM myTable
WHERE to_date(myTable.sdate, 'MM/dd/yyyy') <= {?EndDate}
This works fine, however my only concern is that the date may not always be in the correct format (due to user error). I know that when the to_date function fails it throws an exception.. is it possible to handle this exception in such a way that it ignores the corresponding row in my SELECT statement? Because otherwise my report would break if only one date in the entire database is incorrectly formatted.
I looked to see if Oracle offers an isDate function, but it seems like you are supposed to just handle the exception. Any help would be greatly appreciated. Thanks!!
Echoing Tony's comment, you'd be far better off storing dates in DATE columns rather than forcing a front-end query tool to find and handle these exceptions.
If you're stuck with an incorrect data model, however, the simplest option in earlier versions is to create a function that does the conversion and handles the error,
CREATE OR REPLACE FUNCTION my_to_date( p_date_str IN VARCHAR2,
p_format_mask IN VARCHAR2 )
RETURN DATE
IS
l_date DATE;
BEGIN
l_date := to_date( p_date_str, p_format_mask );
RETURN l_date;
EXCEPTION
WHEN others THEN
RETURN null;
END my_to_date;
Your query would then become
SELECT *
FROM myTable
WHERE my_to_date(myTable.sdate, 'MM/dd/yyyy') <= {?EndDate}
Of course, you'd most likely want a function-based index on the MY_TO_DATE call in order to make this query reasonably efficient.
In 12.2, Oracle has added extensions to the to_date and cast functions to handle conversions that error
SELECT *
FROM myTable
WHERE to_date(myTable.sdate default null on conversion error, 'MM/dd/yyyy') <= {?EndDate}
You could also use the validate_conversion function if you're looking for all the rows that are (or are not) valid dates.
SELECT *
FROM myTable
WHERE validate_conversion( myTable.sdate as date, 'MM/DD/YYYY' ) = 1
If your data is not consistent and dates stored as strings may not be valid then you have 3 options.
Refactor your DB to make sure that the column stores a date datatype
Handle the exception of string to date in a stored procedure
Handle the exception of string to date in a (complex) record selection formula
I would suggest using the first option as your data should be consistent.
The second option will provide some flexibility and speed as the report will only fetch the rows that are needed.
The third option will force the report to fetch every record in the table and then have the report filter down the records.
I have the same problem... an old legacy database with varchar fields for dates and decades of bad data in the field. As much as I'd like to, I can't change the datatypes either. But I came up with this solution to find if a date is current, which seems to be what you're doing as well:
select * from MyTable
where regexp_like(sdate, '[0-1][0-9].[0-3][0-9].[0-9][0-9][0-9][0-9]')
-- make sure it's in the right format and ignore rows that are not
and substr(sdate,7,10) || substr(sdate,1,2) || substr(sdate,4,5) >= to_char({?EndDate}, 'YYYYMMDD')
-- put the date in ISO format and do a string compare
The benefit of this approach is it doesn't choke on dates like "February 30".
Starting from Oracle 12c there is no need to define a function to catch the conversion exception.
Oracle introduced an ON CONVERSION ERROR clause in the TO_DATE function.
Basically the clause suppress the error in converting of an invalid date string (typical errors are ORA-01843, ORA-01841, ORA-011861, ORA-01840) and returns a specified default value or null.
Example of usage
select to_date('2020-99-01','yyyy-mm-dd') from dual;
-- ORA-01843: not a valid month
select to_date('2020-99-01' default null on conversion error,'yyyy-mm-dd') from dual;
-- returns NULL
select to_date('2020-99-01' default '2020-01-01' on conversion error,'yyyy-mm-dd') from dual;
-- 01.01.2020 00:00:00
Solution for the Legacy Application
Let's assume there is a table with a date column stored as VARCHAR2(10)
select * from tab;
DATE_CHAR
----------
2021-01-01
2021-99-01
Using the above feature a VIRTUAL DATE column is defined, that either shows the DATE or NULL in case of the conversion error
alter table tab add (
date_d DATE as (to_date(date_char default null on conversion error,'yyyy-mm-dd')) VIRTUAL
);
select * from tab;
DATE_CHAR DATE_D
---------- -------------------
2021-01-01 01.01.2021 00:00:00
2021-99-01
The VIRTUAL column can be safely used because its format is DATE and if required an INDEX can be set up on it.
select * from tab where date_d = date'2021-01-01';
Since you say that you have "no access" to the database, I am assuming that you can not create any functions to help you with this and that you can only run queries?
If that is the case, then the following code should get you most of what you need with the following caveats:
1) The stored date format that you want to evaluate is 'mm/dd/yyyy'. If this is not the case, then you can alter the code to fit your format.
2) The database does not contain invalid dates such as Feb 30th.
First, I created my test table and test data:
create table test ( x number, sdate varchar2(20));
insert into test values (1, null);
insert into test values (2, '01/01/1999');
insert into test values (3, '1999/01/01');
insert into test values (4, '01-01-1999');
insert into test values (5, '01/01-1999');
insert into test values (6, '01-01/1999');
insert into test values (7, '12/31/1999');
insert into test values (8, '31/12/1999');
commit;
Now, the query:
WITH dates AS (
SELECT x
, sdate
, substr(sdate,1,2) as mm
, substr(sdate,4,2) as dd
, substr(sdate,7,4) as yyyy
FROM test
WHERE ( substr(sdate,1,2) IS NOT NAN -- make sure the first 2 characters are digits
AND to_number(substr(sdate,1,2)) between 1 and 12 -- and are between 0 and 12
AND substr(sdate,3,1) = '/' -- make sure the next character is a '/'
AND substr(sdate,4,2) IS NOT NAN -- make sure the next 2 are digits
AND to_number(substr(sdate,4,2)) between 1 and 31 -- and are between 0 and 31
AND substr(sdate,6,1) = '/' -- make sure the next character is a '/'
AND substr(sdate,7,4) IS NOT NAN -- make sure the next 4 are digits
AND to_number(substr(sdate,7,4)) between 1 and 9999 -- and are between 1 and 9999
)
)
SELECT x, sdate
FROM dates
WHERE to_date(mm||'/'||dd||'/'||yyyy,'mm/dd/yyyy') <= to_date('08/01/1999','mm/dd/yyyy');
And my results:
X SDATE
- ----------
2 01/01/1999
The WITH statement will do most of the validating to make sure that the sdate values are at least in the proper format. I had to break out each time unit month / day / year to do the to_date evaluation because I was still getting an invalid month error when I did a to_date on sdate.
I hope this helps.
Trust this reply clarifies...
there is no direct EXCEPTION HANDLER for invalid date.
One easy way is given below once you know the format like DD/MM/YYYY then below given REGEXP_LIKE function will work like a charm.
to_date() also will work, when invalid_date is found then cursor will goto OTHERS EXCEPTION. given below.
DECLARE
tmpnum NUMBER; -- (1=true; 0 = false)
ov_errmsg LONG;
tmpdate DATE;
lv_date VARCHAR2 (15);
BEGIN
lv_date := '6/2/2018'; -- this will fail in *regexp_like* itself
lv_date := '06/22/2018'; -- this will fail in *to_date* and will be caught in *exception WHEN OTHERS* block
lv_date := '07/03/2018'; -- this will succeed
BEGIN
tmpnum := REGEXP_LIKE (lv_date, '[0-9]{2}/[0-9]{2}/[0-9]{4}');
IF tmpnum = 0
THEN -- (1=true; 0 = false)
ov_errmsg := '1. INVALID DATE FORMAT ';
DBMS_OUTPUT.PUT_LINE (ov_errmsg);
RETURN;
END IF;
tmpdate := TO_DATE (lv_date, 'DD/MM/RRRR');
--tmpdate := TRUNC (NVL (to_date(lv_date,'DD/MM/RRRR'), SYSDATE));
tmpnum := 1;
EXCEPTION
WHEN OTHERS
THEN
BEGIN
tmpnum := 0;
ov_errmsg := '2. INVALID DATE FORMAT ';
DBMS_OUTPUT.PUT_LINE (ov_errmsg || SQLERRM);
RETURN;
END;
-- continue with your other query blocks
END;
-- continue with your other query blocks
DBMS_OUTPUT.PUT_LINE (tmpnum);
END;