I know that ACCESS's time format depends on your Windows time settings. I use ISO-8601 format (YYYYMMDD) so that I can get away with SQL WHERE statements like this one:
WHERE dates > #2020/02/15#
AND dates < #2021/01/30#
If I run the code from above in another computer, whose Windows time settings are for example DDMMYYYY, will the SQL statement no longer work? I could simply do something like this to solve that problem (will it though?):
WHERE dates BETWEEN Format(date1, "\#YYYY\/MM\/DD\#") AND Format(date2, "#YYYY\/MM\/DD\#")
EDIT: Time format has beign changed as pointed out by #Gustav. The question remains; will the first WHERE Statement no longer work on different Windows time settings? Will the second correct the problem?
In Access SQL, use octothorpes:
WHERE dates > #2020/02/15#
AND dates < #2021/01/30#
WHERE dates BETWEEN Format(date1, "\#YYYY\/MM\/DD\#") AND Format(date2, "#YYYY\/MM\/DD\#")
Nope, Windows time settings will mess with a lot of things, but not with ordering or comparisons with dates.
As long as the field is defined as a date (so with octothorpes, like Gustav said), the 2nd of February 2021 will be less the 11th of February 2021, even though that wouldn't be the case if you cast them to a string first.
Always try to keep columns as they are when filtering, so if dates is actually a date column (and not a formatted string), just use WHERE dates BETWEEN #2020/02/15# AND #2021/01/30#, no formats, no funky stuff. And note that especially when trying to keep your application working in all locales, it's important to avoid casting dates to strings, which can happen if you compare a date with a formatted string.
Related
Trying to convert a datetime format column (example value: 12-11-2020 18:15:06) which is actually a nvarchar into this date format: yyyymmdd
This is what I tried so far but I'm getting the following error:
What am I doing wrong?
There are many problems here.
Dates should not be stored as strings.
You lose the ability to perform any kind of date math or extract date parts.
You lose built-in validation (both invalid dates like February 31st and any garbage that doesn't even look like a date).
For example, we have no idea if 12-11-2020 is December 11th or November 12th, or if the data was entered consistently. Imagine a person from the US did some of the data entry and a colleague from Germany did the rest.
FORMAT() is the most expensive way to format a date (see this and this - these are articles about removing time altogether, but the overhead with FORMAT() is the same).
An index on MYDATE can't be used to satisfy this query, so you will do a full table scan every time, which will get worse and worse as the table grows.
You can perform your query in your given scenario without changing anything, but I highly recommend you fix the column and make sure data entry can't be arbitrary (use a date picker or calendar control so you dictate a consistent format).
If 12-11-2020 is December 11th:
WHERE TRY_CONVERT(date, MYDATE, 110) >= #DateVariable;
If 12-11-2020 is November 12th:
WHERE TRY_CONVERT(date, MYDATE, 105) >= #DateVariable;
Note that this still might not get the correct and logical results if some people thought they entered December 11th and others thought they entered November 12th.
You can see all the valid style numbers for CONVERT/TRY_CONVERT here.
I'm trying to get a value using a DlookUp, the problem is access formats my dd/mm/yyyy into mm/dd/yyyy despite using the Format function.
muestraAguasDatos = Nz(DLookup("[name]", "samples", "[location] = '" & location & "' AND ([name] LIKE
'*ACRT*' OR [nombre] LIKE '*CAWQ*') AND [sample_date] = #" & Format(sampleDate, "dd/mm/yyyy") & "#"))
This DLookup works when day value are > 12 but when it's lower and despite having the format it still format it to mm/dd/yyyy
Can you help me solving this issue please?
There are so many misunderstanding with MS Access date fields for non-US residents.
The basic rule is :
Whenever you specify a hardcoded date literal using #the date# notation, in
either :
an SQL query
a query filter criteria
in VBA
in a Dlookup() like you do
You should ALWAYS use the US date format : MM/DD/YYYY, or the ISO format YYYY/MM/DD
The confusion among Access beginners, comes from several things :
In the interfaces, by default, MS Access does an implicit conversion of the dates in the format that is defined on Windows Regional and Language Options setting of the computer. So non-US residents might have the impression that dates are always stored by default in the DD/MM/YYYY format, but that cake is a lie. Dates are stored as numbers, and it is just the display format that changes and is adapted following the computer settings.
In some cases, when you code date literals with #the date# in VBA or a Query, using DD/MM/YYYY format, it just works fine. The reason is date there's a check date algorithm in MS Office that validates a date and modify it to the right format in certain circumstances:
When your date begins by the year, MS Access is smart enough to detect it and it will then consider that your date is enterred in YYYY-MM-DD and do an implicit convertion to MM/DD/YYYY.
If the month part is higher than 12 and lower then 31, then MS Access will understand that this is in fact a DAY, and that you hardcoded the month at the other place. So for instance if you introduce 15th of September like this : #15/09/2019# it will implicitly be transformed in #09/15/2019#. However if you enters the 11th September like this #11/09/2019#, then Access will process it as 09th November !!!
Personal opinion, I have always found this last behavior plain stupid, because it may introduces a lot of troubles on applications of people not acquainted by that mechanism, and that tracking where the problems comes can be very tedious. It's sneaky, it should not be there. Much better to raise an error if the format is wrong.
I have a SQL db that I need to filter results based on the month that inventory items were completed in order to do the billing.
The field I'm working with is called CompletionDate. Here is the code I'm using.
input name='criteria' type='hidden' value="WHERE CompletionDate BETWEEN '8-1-2013' AND '8-31-2013'"
I get some of the records returned but not all. I suspect that the problem lies in the format of the CompletionDate field. It is currently a varchar(10). I am storing the data in this field in the format MM-DD-YYYY.
After some searching I understand that since the field is in a varchar datatype that the above mentioned code is not going to work the way I want it to. I've tried this to no avail.
input name='criteria' type='hidden' value="WHERE to_date(CompletionDate, 'mm-dd-yyyy') BETWEEN to_date('8-1-2013', 'mm-dd-yyyy') AND to_date('8-31-2013', 'mm-dd-yyyy')"
Can anyone help guide me to the solution?
Because the field is of type varchar, you are not searching for a date range but actually a text range. You really should store dates in a date type field, because then you can easily and efficiently do date range queries.
Your workaround using to_date should in theory work, although it is rather inefficient as the database has to try to convert the text from each row into a real date in order to be able to do the comparison. As to why it actually does not work is still unclear. What database are you using? Is the format string correct or should it be in uppercase ('MM-DD-YYYY')?
If you are stubborn in storing dates as text in the database, using a format that can be lexically sorted, e.g. YYYY-MM-DD including leading zeroes (2013-08-01), can seemingly make the range queries work. But there really are several good reasons why databases have dedicated date datatypes!
A better way is like this:
where CompletionDate >= the start of your date range
and CompletionDate < the day after the end of your date range.
Reason number 1 is that it will take the time element into account, if applicable.
Reason number 2 is that using functions in the where clause slows down production.
By the way, if CompletionDate is a char or varchar datatype in your db, you have serious problems.
I was wondering if there was a way to store a date (example: 01/01/2013) as datetime without SQL Server CE adding the time (example: 12:00:00 AM).
I could always store it as the string "01/01/2013" but I really want to be able to compare the dates on querying the database.
I realize that as long as I only stored the date part, all of the times in the datetime field would have equal values (i.e. 12:00:00 AM), so comparing them wouldn't be a problem and I could just always ignore the time part, however, it seems ridiculous to have this unnecessary data appended to every entry in the table.
Is there a way to store only the date part of the datetime as datetime so that the dates can still be compared in the SQL query or do I just need to live with this overhead and move on?
Side Note:
I just spent the last 30 minutes searching Google and SO for an answer I was sure was already out there, but to my surprise, I couldn't find anything on this issue.
Update:
The conclusion I have come to is that I will just accept the time in the datetime format and let it always default to 12:00:00 AM by only adding the date part during the INSERT statement (e.g. 01/01/2013). As long as the time part always remains the same throughout, the dates will still be easily comparable and I can just trim it up when I convert it to string for screen display. I believe this will be the easiest way to handle this scenario. After all, I decided to use SQL for the power of its queries, otherwise, I might have just used XML instead of a database, in the first place.
No you really can't get rid of the time component. It is part of the data type defined by sql server. I was very annoyed by it until I found that I could still display the dates without the time using JQuery to reformat them with the date formatter plugi:
https://github.com/phstc/jquery-dateFormat
Good Luck!
select CONVERT(date, GETDATE())
I have a date in the format [last two year][day of 365]. Using either SQL or excel functions, I need to determine the date this pertains to. The year is always the last two of the 2000s. There are no dates from before 2007. Is there a way to easily do this? I'm using this for a quick check, and am trying to avoid a large coding time for this.
In SQL, the date-handling functions seem to vary widely by SQL vendor, and there don't seem to be any good standard ways of handling date offsets. However, if you were a bit more specific about the specific SQL server you're using, someone might be able to provide an answer that applies.
In Excel, you can build a date for the first day of the year (e.g. 2008-01-01) and then add the number of days numerically, subtracting 1 so that the first day is still 2008-01-01; the resulting value, when formatted as a date, should be the precise date value. For example, =DATE(2008,1,1)-1+320 returns a date of 11/15/08 (at least in LibreOffice Calc).
You can try this formula in Excel where your data is in A1
=DATE(LEFT(A1,2)+100,1,RIGHT(A1,3))