I'm reporting out of a database that is using decimal(17,6) as the datatype for a date field. For example, the current date/time in this field would be 20210820.171900. Unusual, but whatever. I need to convert the original date field from decimal(17,6) to datetime. This is what I have:
SELECT convert(datetime, convert(varchar,convert(int, lastmoddatetime)), 0)
from Table1
The above statement works correctly as long as none of the records have a value of zero in this column. Unfortunately, the column value defaults to zero (0.000000) if no date has been calculated for it. Whenever a column has a zero value, I get the following error:
Conversion failed when converting date from character string.
How can I overcome this issue? Ultimately, I'm needing to apply a dateadd function to the lastmoddatetime field.
Note: Before you suggest changing the column definition, this database originated in the 1990's and I'm not allowed to make any changes to the database structure.
You can use NULLIF to null out those values
convert(datetime, convert(varchar(15), convert(int, NULLIF(lastmoddatetime, 0.0))), 0)
Either use TRY_CONVERT or CASE - depending how you want to handle the zero case.
SELECT
-- If desiring null for 0 and SQL Server 2012+
TRY_CONVERT(date, CONVERT(varchar, CONVERT(int, lastmoddatetime)), 0)
, CASE WHEN lastmoddatetime <> 0
-- If desiring some other valid date or < SQL Server 2012
THEN CONVERT(date, CONVERT(varchar, CONVERT(int, lastmoddatetime)), 0)
ELSE NULL /* Whatever valid datetime value you want */ END
FROM (
VALUES (20210820.171900), (0.0)
) x (lastmoddatetime);
I note that this ignores the time component - so am converting to a date not datetime above. If you need to handle the time component you need to update your question.
Yet another option.
You can thin it out a bit by using left() and try_convert()
Example
Declare #YourTable table (lastmoddatetime numeric(17,6))
Insert into #YourTable values
(20210820.171900)
,(0.0)
Select AsDate = try_convert(date,left(lastmoddatetime,8))
,AsDateTime = try_convert(datetime,left(lastmoddatetime,8))
From #YourTable
Results
AsDate AsDateTime
2021-08-20 2021-08-20 00:00:00.000
NULL NULL
use
convert(datetime,convert(int,lastmoddatetime),0)
Related
I have a table where there are values like 20170730 and also 0 values are there which is INT type
I am trying to convert it to value like 30/07/2017, for which i am using the below code,
Select convert(NVARCHAR(10),convert(date,convert(NCHAR(8),datecolumn)),103) from table
But for the zero values i am getting the below error
Conversion failed when converting date and/or time from character string.
If i delete all the zero this working fine but problem having with zero.
My requirement is to convert when there a date value and if 0 are there then it should be zero only like below,
Result
30/07/2017
0
Can u pls help
As already pointed out in the comments, you can try to use a CASE expression
SELECT CASE
WHEN nmuloc = 0 THEN
'0'
ELSE
convert(varchar(10),
convert(date,
convert(varchar(8),
nmuloc),
112),
103)
END
FROM elbat;
or try_convert() and coalesce().
SELECT coalesce(convert(varchar(10),
try_convert(date,
convert(varchar(8),
nmuloc),
112),
103),
'0')
FROM elbat;
db<>fiddle
The latter one will also correct other "malformed" data like 123 for example. The former will also fail in such cases. You may want that or not.
But, as also already pointed out in the comments, your real problem is that you use an inappropriate data type. Change the column's datatype to some date/time data type to really fix this.
I've got a table that currently has all columns stored as nvarchar(max), so I'm converting all the datatypes to be what they should be. I have a column of dates, however when I run this:
ALTER TABLE Leavers ALTER COLUMN [Actual_Termination_Date] date;
I get
"Conversion failed when converting date and/or time from character string".
This is relatively normal, so I did the following to investigate:
SELECT DISTINCT TOP 20 [Actual_Termination_Date]
FROM LEAVERS
WHERE ISDATE([Actual_Termination_Date]) = 0
which returned:
NULL
13/04/2017
14/04/2017
17/04/2017
19/04/2017
21/04/2017
23/04/2017
24/04/2017
26/04/2017
28/04/2017
29/03/2017
29/04/2017
30/04/2017
31/03/2017
42795
42797
42813
42817
42820
42825
The null and excel style date formats (e.g. 42795) are no problem, however it's the ones appearing as perfectly normal dates I'm having a problem with. I usually fix issues like this by using one of the following fixes:
SELECT cast([Actual_Termination_Date] - 2 as datetime)
FROM LEAVERS
WHERE ISDATE([Actual_Termination_Date]) = 0
or
SELECT cast(convert(nvarchar,[Actual_Termination_Date], 103) - 2 as datetime)
FROM LEAVERS
WHERE ISDATE([Actual_Termination_Date]) = 0
When these return back the dates as I would expext, I'd then do an UPDATE statement to change them in the table and then convert the column type. However I keep getting an error message telling me that various dates can't be converted such as:
Conversion failed when converting the nvarchar value '21/04/2017' to data type int.
Any thoughts? Thanks!
Probably because of your language setting. For '21/04/2017' to work, you'll need to be using the BRITISH language, or other language that uses dd/MM/yyyy. I suspect you are using ENGLISH which is actually American.
American's use MM/dd/yyyy meaning that '21/04/2017' would mean the 4th day of the 21st month in the year 2017; obviously that doesn't work.
The best method is to use an unambiguous format, regardless of language and data type. For SQL Server that's yyyyMMdd and yyyy-MM-ddThh:mm:ss.nnnnnnn (yyyy-MM-dd and yyyy-MM-dd hh:mm:ss.nnnnnnn are not unambiguous in SQL Server when using the older datetime and smalldatetime data types).
Otherwise you can use CONVERT with a style code:
SELECT CONVERT(date,'21/04/2017', 103)
The problem with your data, however, is that you have values that are in the format dd/MM/yyyy and integer values. The int (not varchar) value 42817 as a datetime in SQL Server is 2017-03-25. On the other hand, if this data came from Excel then the value is 2017-03-23. I am going to assume the data came from Excel, not SQL Server (because the ACE drivers have a habit of reading dates as numbers, because the thing they aren't is "ace").
You'll need to therefore convert the values to an unambiguous format first, so that'll be yyyyMMdd. As we have 2 different types of values, this is a little harder, but still possible:
UPDATE dbo.Leavers
SET Actual_Termination_Date = CONVERT(varchar(8), ISNULL(TRY_CONVERT(date, Actual_Termination_Date, 103), DATEADD(DAY, TRY_CONVERT(int, Actual_Termination_Date),'18991230')), 112);
Then you can alter your table:
ALTER TABLE dbo.Leavers ALTER COLUMN [Actual_Termination_Date] date;
DB<>Fiddle using Michał Turczyn's DML statement.
Put the column into a canonical format first, then convert:
update leavers
set Actual_Termination_Date = try_convert(date, [Actual_Termination_Date], 103);
ALTER TABLE Leavers ALTER COLUMN [Actual_Termination_Date] date;
The update will do an implicit conversion from the date to a string. The alter should be able to "undo" that implicit conversion.
Back up the table before you do this! You are likely to discover that some dates are not valid -- that is pretty much the rule when you store dates as strings although in a small minority of cases, all date strings are actually consistently formatted.
The actual date does not matter. The error happens when you try to subtract 2 from a string:
[Actual_Termination_Date] - 2
The clue comes from the error message:
Conversion failed when converting the nvarchar value '21/04/2017' to data type int.
To fix the problem, use DATEADD after the conversion:
SELECT DATEADD(days, -2, convert(datetime, [Actual_Termination_Date], 103))
You just have inconsistent date format within your column, which is terrible.
Having wrong datatype lead to it, that's why it is so important to have proper data types on columns.
Let's investigate it a little:
-- some test data
declare #tbl table (dt varchar(20));
insert into #tbl values
(NULL),
('13/04/2017'),
('14/04/2017'),
('17/04/2017'),
('19/04/2017'),
('21/04/2017'),
('23/04/2017'),
('24/04/2017'),
('26/04/2017'),
('28/04/2017'),
('29/03/2017'),
('29/04/2017'),
('30/04/2017'),
('31/03/2017'),
('42795'),
('42797'),
('42813'),
('42817'),
('42820'),
('42825');
-- here we handle one format
select convert(date, dt, 103) from #tbl
where len(dt) > 5
or dt is null
-- here we handle excel like format
select dateadd(day, cast(dt as int), '1900-01-01') from #tbl
where len(dt) = 5
So, as you can see you have to apply to different approaches for this task. CASE WHEN statement should fit here nicely, see below SELECT:
select case when len(dt) = 5 then
dateadd(day, cast(dt as int), '1900-01-01')
else convert(date, dt, 103) end
from #tbl
I have a varchar column in my database table, on the row I would like to return it is populated as '2018-12-26T00:00:00.000' (quotes mine, not included in actual value). When I try to query for this value whenever it is a valid date, e.g.
SELECT
myValue
FROM
myTable
WHERE
ISDATE(myValue) = 1
it returns properly. However, I need this value to be converted to DATE. When I try something like this:
SELECT
CAST(myValue AS DATE) AS myValueFormatted
FROM
myTable
WHERE
ISDATE(myValue) = 1
I get an error
Conversion failed when converting date and/or time from character string
Is there any other way I can convert this varchar value to Date?
UPDATE: I've noticed through trying some different things, the query seems to be fine with me using the value as a date for anything (DATEDIFF, CONVERT back to string, etc.) in the select portion, but trying to do anything with it in the WHERE clause causes the error. To ensure nothing else is interfering, I created a temp table with only 1 row with the data value above, and running the query just against that one value gives the error
UPDATE 2: Ok, I have no idea why this fixes it, but this is what I found. When I run
SELECT
myValue
FROM
myTable
WHERE
TRY_CONVERT(DATE, myValue) IS NOT NULL
it returns EXACTLY the same values as
SELECT
myValue
FROM
myTable
WHERE
ISDATE(myValue) = 1
However, when I then add AND CAST(myValue AS DATE) < GETDATE() to each WHERE clause, only the first one works. I understand why TRY_CONVERT is safer to use, I'm still not sure why it works over GETDATE()
I can't reproduce your error...
declare #dt varchar(256) = '2018-12-26T00:00:00.000'
select cast(#dt as date)
So, there must be another rogue value in there that can't be converted.
To identify what value is causing the issue on versions < 2012, run this:
SELECT
myValue
FROM myTable
WHERE
ISDATE(myValue) = 0
Note, ISDATE is deterministic only if you use it with the CONVERT function, if the CONVERT style parameter is specified, and style is not equal to 0, 100, 9, or 109.
For 2012 onward, use TRY_CONVERT
SELECT
*
FROM myTable
WHERE
TRY_CONVERT(date, myValue) IS NULL
You could also just try something like this:
SELECT CAST(LEFT(MyValue, 10) AS DATE)
If it still doesn't work, you have some formatting issues with your data.
This helped me....
CAST string as varchar(30) then cast the varchar as datetime2
CAST(CAST(REPLACE(['Timestamp' ],'''','') AS varchar(30)) as datetime2)
I have VARCHAR column (MyValue) in my table. It has date value in two different format.
MyValue
----------
25-10-2016
2016-10-13
I would like to show them in DATE format.
I wrote query like below:
SELECT CONVERT(date, MyValue, 105) FROM MyTable
SELECT CAST(MyValue as date) FROM MyTable
Both are giving me this error. Conversion failed when converting date and/or time from character string.
Is there anyway convert to DATE datatype format even the value stored in different formats like above?
Expecting your answers. Thanks in advance.
Does this help?
declare #varchardates table
(
vcdate varchar(20)
)
INSERT INTO #varchardates VALUES
('25-10-2016'),
('2016-10-13')
SELECT CONVERT(date,vcdate, case when SUBSTRING(vcdate, 3, 1) = '-'
THEN 105 ELSE 126 END) as mydate
FROM #varchardates
Depending on how many different formats you have in your data, you may need to extend the case statement!
See here for list of the different format numbers
You can use TRY_CONVERT and COALESCE. TRY_CONVERT returns NULL if the conversion fails, COALESCE returns the first NOT NULL value:
SELECT COALESCE(TRY_CONVERT(DATETIME, x, 105), TRY_CONVERT(DATETIME, x, 120))
FROM (VALUES('25-10-2016'), ('2016-10-13')) a(x)
I assumed the value 2016-10-13 is in format yyyy-MM-dd.
You mention in a comment you may have other formats as well. In that case it gets very tricky. If you get a value 01-12-2017 and you have no idea about the format, there is no way to tell whether this is a date in januari or in december.
I have a main table called Cases that I am inserting data into. I have a alternative table where all of the raw data called rawTableData is stored and then sent to the main table.
I have a nvarchar column in my rawTableDatathat stores a datetime string in this format
2016-04-04-10.50.02.351232
I have a column in my Cases table that has a datatype of DATETIME.
I first tried to find the bad data in this method below
SELECT CONVERT(datetime, nvarcharDateColumn, 103)
FROM rawTableData
WHERE ISDATE(CONVERT(datetime, nvarcharDateColumn, 103)) != 1
And I get the error below
The conversion of nvarchar data type to a datetime data type resulted in an out-of-range value.
Then I tried a different approach hoping to find all of the out of range values
SELECT nvarcharDateColumn
FROM rawTableData
WHERE ISDATE(nvarcharDateColumn)
But that only returns all rows since its nvarchar.
Again, I kept going and tried a different approach
SELECT CONVERT(DATETIME, CASE WHEN ISDATE(nvarcharDateColumn) = 1 THEN nvarcharDateColumn END, 103)
FROM rawTableData
I am not sure what I am doing wrong here and any help would be appreciated.
I am using SQL Server 2012
You can use TRY_CONVERT:
SELECT nvarchardatecolumn, TRY_CONVERT(date, nvarchardatecolumn)
FROM rawTableData
And if you only want to return the invalid dates, use a derived table:
SELECT *
FROM (SELECT nvarchardatecolumn, TRY_CONVERT(date, nvarchardatecolumn) DateCheck
FROM rawTableData
) A
WHERE DateCheck IS NULL