I am using SQL Server Management Studio 18 against SQL Server 2016. I have some material that are in batches and those batches have expiration dates that are held as strings, but are basically in the format of 'yearmonthday', e.g. '20210312' for March 3rd, 2021. My goal is to only see material that is expiring after the current date. Whenever I try to CAST the expiration date column AS DATE within the WHERE clause, I get this error:
Conversion failed when converting date and/or time from character string
(or something similar when trying different methods).
So, right now my code looks like this:
SELECT MaterialColumn, BatchColumn, CAST(ExpirationColumn AS DATE)
FROM StockTable
WHERE CAST(ExpirationColumn AS DATE) > CAST(GETDATE() AS DATE)
If I don't do the WHERE clause, I know I can CAST the ExpirationColumn as DATE without issue, but when it's in the WHERE clause, I run into that error. Is there any way I can filter to see only the dates that I want?
You can use try_cast() instead:
SELECT MaterialColumn, BatchColumn, CAST(ExpirationColumn AS DATE)
FROM StockTable
WHERE TRY_CAST(ExpirationColumn AS DATE) > CAST(GETDATE() AS DATE);
You can also find the bad values:
SELECT ExpirationColumn
FROM StockTable
WHERE TRY_CAST(ExpirationColumn AS DATE) IS NULL AND ExpirationColumn IS NOT NULL;
It sounds like you might need to fix some data values.
Honestly, if your dates are all stored in the format yyyyMMdd then there's no need to convert. Instead use a varchar parameter, as (at least) a varchar in the format yyyyMMdd had the same sort order as a date.
As a result you just convert GETDATE to the right format:
WHERE Expiration > CONVERT(varchar(8), GETDATE(), 112)
Of course, this doesn't change my statements in the comment; fix your design, don't stores dates as a string but as a date (and time) data type.
Related
I'm trying to parse certain columns into a date format and have had success doing so, but have run into an error due to inconsistency that lies in the data.
My date columns are currently integers in the form of YYYYMMDD, so I've used the following in the select statement to parse into dates:
CONVERT(datetime, CAST(date_column AS CHAR(8)), 112)
This works as expected, transforming my data into a YYYY-MM-DD format.
I run into the following error though:
Conversion failed when converting date and/or time from character
string.
After looking through the data a bit, it turns out I have some cases of inconsistent data values, such as -1 and 10630 instead of the expected YYYYMMDD value.
Do I just need to add a WHERE statement to only apply CONVERT and CAST to YYYYMMDD fields while filtering out fields with bad data? If so, how would I do this, or is there a better way?
Thanks in advance
Let me assume you are using SQL Server, based on the syntax of your SQL. You shouldn't actually need the 112. 'YYYYMMDD' is the default date format for SQL Server.
In any case, you can use TRY_CONVERT():
TRY_CONVERT(datetime, CAST(date_column AS CHAR(8)), 112)
This returns NULL if the value cannot be converted. You can find the offending values using:
select date_column
from t
where try_convert(datetime, cast(date_column as char(8)) is null and
date_column is not null;
Use Parse() or Try_parse()
select parse('22-JAN-1989' as date)
select parse('04-March-1992' as date)
select parse('03/10/2020' as date)
select parse('07-05-1958' as date)
select parse('Aug 25,2016' as date)
Every example above returns a valid date.
You can also add USING 'en-US' or such if you want a different culture.
If you are getting numeric values, and you know the starting date, use
select IsNull(try_parse('16500' as date),dateadd(d,cast('16500' as int),'1/1/1980'))
I have a little query that strips the date from the datetime field but when I try to convert it from GMT to CST it readds the date. Is there a better way to do this?
Location table:
arrival
4-6-2018 12:35:43
SELECT arrival
FROM(
SELECT CONVERT(VARCHAR(8), arrival))
FROM locations
)a
This query will give me this result:
12:35:43
SELECT (DATEADD(hour,-5,arrival))
FROM(
SELECT CONVERT(VARCHAR(8), arrival))
FROM locations
)a
4-6-2018 12:35:43
This query will give readd the date. How can I remove the date and then do the dateadd function without it readding the date
arrival seems to be a DateTime, which always carries a date part. You need a time instead, supported by SQL Server 2008+:
cast(DATEADD(hour,-5,arrival) as time)
To quote from DATEADD (Transact-SQL) - Return Types:
The return data type is the data type of the date argument, except for string literals. The return data type for a string literal is datetime. An error will be raised if the string literal seconds scale is more than three positions (.nnn) or contains the time zone offset part.
Emphasis my own.
As you are passing a string (varchar), then DATEADD is returning a datetime.
Like those in the comments have said, if you use the correct data type (time) this problem goes away:
SELECT DATEADD(HOUR, -5,CONVERT(time,Arrival))
FROM (VALUES('4-6-2018 12:35:43'),('4-6-2018 07:35:43'),('4-6-2018 03:35:43')) V(Arrival)
Probably this is what you are asking for:
SELECT Convert(Varchar(8), DATEADD(hour,-5,arrival), 108)
FROM locations;
Note: This is compatible with SQL server versions that doesn't have Time datatype too.
I have dates currently stored as varchar(1000) that are in inconsistent formats. I.e. yyyy-mm-dd and dd-mm-yyyy etc.
What query can I run to clean these up so they are in a consistent format, so I can convert the column datatype from varchar(1000) to date?
Thanks
This could get ugly if you have many different date formats, possibly including invalid data. One option would be to assign a new date column using a CASE expression to choose the correct format mask:
UPDATE yourTable
SET date_col = CASE WHEN date LIKE '[0-9]{2}-[0-9]{2}-[0-9]{4}'
THEN CONVERT(datetime, date, 105)
WHEN date LIKE '[0-9]{4}-[0-9]{2}-[0-9]{2}'
THEN CONVERT(datetime, date) END;
You may add conditions to the above CASE expression for other date formats.
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.
In a SQL Server table, I have a field named Timestamp, which is a 'datetime' field. On a screen I have created, a user will pass in a date (no time), and I need to return all the records for that date.
Just doing Timestamp = #Date doesn't seem to work unless the time in the field is 00:00:00. What is the most efficient way of doing this?
Since you're on SQL Server 2008, you can use the DATE datatype.
Do a comparison between
CAST(Timestamp AS DATE) = #Date
That should work and look just at the date - no time portion.
In general you should think about the data from a specific date as data that falls in a range, not at a single point in time. So ideally your query should use a range, such as:
WHERE [Timestamp] >= #Date
AND [Timestamp] < DATEADD(DAY, 1, #Date)
In this case, luckily, the optimizer is smart and will still use an index if you use CONVERT(DATE, [timestamp]) against the column. However in a lot of cases you need to be careful because this will often make your clause non-sargable.
PS Timestamp is a horrible column name. It's a data type in SQL Server which has nothing to do with date or time.
A common technique for truncating the time part off a datetime value is to use the DATEDIFF and DATEADD functions. In your example it would be used like this to truncate the time part of the Timestamp field.
WHERE #DateEntered = DATEADD(DAY,0, DATEDIFF(DAY, 0, Timestamp))
Bascially it's taking the datetime value and finding the name of days since "the date represented by 0" (for lack of a better description) and then adding that number of days back. This effectively truncates time part.