I hope I will be forgiven for transgressing the rules ever so slightly by asking for a reason, rather than a solution.
I have the following code:
INSERT INTO destinationTable (RecordMonth, ...)
SELECT t1.Expr1, ...
FROM
(
SELECT
CDate(Format("01-" & Right([t1].[Year-Month],2) & "-" & Left([t1].[Year-Month],4),"dd/mm/yyyy")) AS Expr1,
/* ...other fields with no bearing... */
FROM tcsvMonthData AS t1
)
WHERE t1.Expr1 >= DateAdd("m",-6,(SELECT MAX(Expr1) FROM t1))
[Year-Month] in t1 is a varchar-type field.
This script fails, Access gives the following error message: "Data type mismatch in criteria expression."
If I remove the CDate block the script will work. Happy to have found the answer but I don't understand why the error occurs in the first place. CDate constrains a field to a date type. After format the field should be a date type already, so CDate is redundant, but it should not harm (not in my head, at least). Also, as far as I know DateAdd unlike say, Year, does not convert the input field to a string, it should maintain a date type. So what is going on here?
EDIT:
Year-Month describes the month the record occurred in and it looks like this: 2017-11. It is a varchar type and the goal is to have it as a proper datetime field in dd/mm/yyyy format where each month is represented by the first day of that month. So May is 01/05/2018 etc.
You are seriously overcomplicating this. CDate is all you need:
CDate([t1].[Year-Month]) AS Expr1
Edit:
To accept Null values, either filter these out, or use CVDate to either pass Null on:
CVDate([t1].[Year-Month]) AS Expr1
or supply a default value using Nz:
Nz(CVDate([t1].[Year-Month]), Date()) AS Expr1
I have found a solution in sql server please use cdate in place of cast for ms access.
select cast(format(cast('01-' + left('07/23/2018',2) + '-' + right('07/23/2018',4) as date),'dd/MM/yyyy') as date) AS Expr1
change the static date with your column.
It’s been a long time since I have had to use Access but I think the problem isn’t with your use of CDate() but rather the use of Format() on the internal string. Format() needs to operate on a date, but you are giving it a string. Because Format is failing, the surrounding CDate() is failing as well.
You need to use CDate () before Format() like this:
Format(CDate ("01-" & Right([t1].[Year-Month],2) & "-" & Left([t1].[Year-Month],4),"dd/mm/yyyy")) AS Expr1,
You may need to do some tweaking to get that to run but the basic idea should work.
The rejected answer below works because Cast As Date (which is functionally equivalent to CDate) is used both before and after Format() so Format() is being passed a Date. The 2nd Cast in that example is redundant.
Related
I should preface my question by saying I am very new to SQL (or any programming involving databases). I started learning SQL a couple of weeks ago when I decided to take on a data project.
I have been using SSMS in wrangling large tables in comma-separated text file format. I need to be able to sort by dates, and the current format is mmddyyyy, but when I try to sort by date it does not work.
I know that converting dates is something that gets asked a lot around here, but I haven't found any solutions that explain things for a newb like myself.
So far my guesses for a solution are to use the CONVERT or CAST solutions, but I'm not sure if that is the right approach. I have found several CAST/CONVERT posts but none have really applied to my situation.
I hate to have this as my first question, but I'd thought I'd take some down vote bullets if it means I could figure this out. Thank you.
Sample of what I'm trying to do:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE [ column1] > 01012017;
I get the entire table back, unsorted.
Since your:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE [ column1] > 01012017;
does not error, we could say that the [column1]'s datatype is either a character type (like VARCHAR, char), or datetime.
Since you are getting back all the data and I would think you don't have data in the future, it should be a varchar (or char) - with datetime that means 1900-01-01 + 1012017 days.
To make it a datetime you need to 'cast' your column1 which is in mmddyyyy form by first converting it to yyyymmdd style (which would work under any date and language setting):
cast(right([column1],4)+substring([column1],1,2)+substring([column1],3,2) as datetime)
and you would write that 01012017 as a string (quotes around) and also again in yyyymmdd format (it would be implicitly casted to datetime):
'20170101'
So your SQL becomes:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE cast(right([column1],4) +
substring([column1],1,2) +
substring([column1],3,2) as datetime) > '20170101';
Having a date\datetime column as varchar and using like this would render the ability to use simple indexes but that is another matter. For now, this would return the data you want.
Assuming your column's datatype is [Date], try something similar to:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE FORMAT([column1],'dd/MM/yyyy') >'01012017'
If it's string format, you'll have to use CONVERT() to convert the column to Date with a query like
SELECT *
FROM [databasename].[dbo].[table1]
WHERE CONVERT(NVARCHAR(10), [Column1], 112) >'01012017'
Refer to this W3Schools article if you need more help with the CONVERT clause
I am trying to achieve this use case: when there is no date picked I want to show all the results but when I have date picked I want it to filter.
fyi:
the date getting picked are YYYY-MM-DD HH24:MI:SS in the presentation variable, but the date format in my query is dd-mon-yy. So when I need to convert the value of the presntation varible to dd-mon-yy.
OBIEE doesnt like when I play around with the values, and the BI server does not let me look at the error message.
I dont have access to change the format on the server level so my only option is to use formulas
I'm new to presentation variable.
ALso I need you'll to remember if there is no date selected in the prompt I would want all values returned
code:
and
( ( main_query.schd_compare >= (#{pv_task_sch_st_date}['#']{NVL(main_query.schd_compare,'None')})
)
AND (
main_query.schd_compare <= (#{pv_task_sch_end_date}['#']{NVL(main_query.schd_compare,'None')})
) )
I need help with syntax for obiee
Inside the database, it doesn't care if a date is "DD Mon YY" or "YYYY-MM-DD HH24:MI:SS". Those are just formatting, and the actual bit value of that date will be the same. So if both "dates" are actually a date datatype, then you can just use something like:
....
AND (
(
main_query.schd_compare >= NVL(pv_task_sch_st_date,main_query.schd_compare)
)
AND
(
main_query.schd_compare <= NVL(pv_task_sch_end_date,main_query.schd_compare)
)
)
That's if your pv_task_sch_???_date are passed as NULL values when not selected. Oracle does seem to treat empty strings and NULL the same in comparisons like this, but you it can be hard to debug if you get in the habit of relying on NULL and '' being the same.
As for your query, my guess is that your pv_task... values are actually being passed to your query as a some sort of string. If that's the case, then you'll need to put a TO_DATE() around your pv_task... variables.
Take a look at https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=2066b2005a22769e785815f6b03750a1. I stepped through a few examples of how your dates can be treated.
I did say earlier that the database doesn't care when format your date is in. And it is stored the same, no matter the format. But when you're using TO_DATE() or other similar functions, Oracle wants you to specify the proper mask of your data. If you send "01 Jan 99" to TO_DATE(), Oracle needs to know how to interpret that value. So you tell it that the string is "DD Mon YY". You can't do TO_DATE('2018-09-10','YYYY-MM-DD HH24:MI:SS') because my input doesn't have a time component. ( I would also caution about using 2-digit years. )
By the way, I hate dates. And dealing with dates in Oracle reinforces that hatred.
I have a question regarding SQL dates.
The table I am working with has a date field in the following format: "22-SEP-08". The field is a date column.
I am trying to figure out how to output records from 1/1/2000 to present day.
The code below is not filtering the date field:
Select distinct entity.lt_date
from feed.entitytable entity
where entity.lt_date >= '2000-01-01'
Any help regarding this issue is much appreciated. Thanks!
Edit: I am using Oracle SQL Developer to write my code.
DATEs do not have "a format". Any format you see is applied by the application displaying the date value.
You can either change the configuration of SQL Developer to display dates in a different format, or you can use to_char() to format the date the way you want.
The reason your statement does not work, is most probably because of the implicit data type conversion that you are relying on.
'2000-01-01' is a string value, not a date. And the string is converted using the NLS settings of your session. Given the fact that you see dates displayed as DD-MON-YY means that that is the format that is used by the evil implicit data type conversion. You should supply date values always as real date literals.
There are two ways of specifying a real date literal. The first is ANSI SQL and simple uses the keyword DATE in front of an ISO formatted string:
where entity.lt_date >= DATE '2000-01-01'
Note the DATE keyword in front of the string, wich makes it a real date literal not a string expression.
The other option is to use to_date() to convert a character value into a date:
where entity.lt_date >= to_date('2000-01-01', 'yyyy-mm-dd');
More details about specifying date literals can be found in the manual:
Date literals
to_date function
My guess is the data type isn't a Date. Just in case its a char type, try to convert it using the Oracle TO_DATE() function. The Oracle documentation below should help you with parameters.
http://docs.oracle.com/cd/B19306_01/server.102/b14200/functions183.htm
An implicit datatype conversion bites once again.
You're right. The predicate is not doing the comparison you are expecting,
Oracle is performing an implicit datatype conversion, from DATE to VARCHAR, so that it can do a comparison to the string literal.
If lt_date column is DATE datatype, then Oracle is seeing your where clause:
where entity.lt_date >= '2000-01-01'
Oracle is actually seeing it as if it's written like this:
where TO_CHAR(entity.lt_date) >= '2000-01-01'
And that's where the "format" problem comes in. The column itself does not have a "format". Because the second argument to the TO_CHAR function is not supplied, Oracle is using the value of the NLS_DATE_FORMAT parameter (from your session). And that's probably set to DD-MON-YY. Which is why that's the "format" you're seeing when you a run a SELECT statement in SQL*Plus. Because the DATE value is (again) being run through a TO_CHAR function to get a string that can be displayed.
To get the "filtering" you want, don't do a comparison to a string literal. Instead, do the comparison to an expression that has DATE datatype.
You can use the Oracle TO_DATE function. And you don't want to rely on setting of NLS_DATE_FORMAT, explicitly specify the format model as the second argument to the function. For example:
DO THIS
where entity.lt_date >= TO_DATE('2000-01-01','YYYY-MM-DD')
DON'T DO THIS
It's also possible to specify the format model as the second argument to the TO_CHAR function.
where TO_CHAR(entity.lt_date,'YYYY-MM-DD') >= '2001-01-01'
But you don't want to do that because that's going to force Oracle to evaluate that expression on the left side for every flipping row in the table, so it has a string value to do the comparison. (That's true unless someone created a function-based index for you.) If you do the comparison on the bare column, using the TO_DATE on the literal side, Oracle can make effective use of an appropriate index (with lt_date as the leading column) to satisfy the predicate.
I have a table and need to verify that a certain column contains only dates. I'm trying to count the number of records that are not follow a date format. If I check a field that I did not define as type "date" then the query works. However, when I check a field that I defined as a date it does not.
Query:
SELECT
count(case when ISDATE(Date_Field) = 0 then 1 end) as 'Date_Error'
FROM [table]
Column definition:
Date_Field(date, null)
Sample data: '2010-06-27'
Error Message:
Argument data type date is invalid for argument 1 of isdate function.
Any insight as to why this query is not working for fields I defined as dates?
Thanks!
If you defined the column with the Date type, it IS a Date. Period. This check is completely unnecessary.
What you may want to do is look for NULL values in the column:
SELECT SUM(case when Date_Field IS NULL THEN 1 ELSE 0 end) as 'Date_Error' FROM [table]
I also sense an additional misunderstanding about how Date fields, including DateTime and DateTime2, work in Sql Server. The values in these fields are not stored as a string in any format at all. They are stored in a binary/numeric format, and only shown as a string as a convenience in your query tool. And that's a good thing. If you want the date in a particular format, use the CONVERT() function in your query, or even better, let your client application handle the formatting.
ISDATE() only evaluates against a STRING-like parameter (varchar, nvarachar, char,...)
To be sure, ISDATE()'s parameter should come wrapped in a cast() function.
i.e.
Select isdate(cast(parameter as nvarchar))
should return either 1 or 0, even if it's a MULL value.
Hope this helps.
IsDate takes a character string or exression that yeilds a character string as it's argument
The problem is this method ISDATE() only admits arguments of type datetime and smalldatetime within the "time" types, so it won´t work if you are using date type.
Also if you use date as type for that field, you won´t have to check the information there because it won´t admit other type of field.
You shoul only check for null values in your column, that´s all.
I have a query in which I want to select data from a column where the data is a date. The problem is that the data is a mix of text and dates.
This bit of SQL only returns the longest text field:
SELECT MAX(field_value)
Where the date does occur, it is always in the format xx/xx/xxxx
I'm trying to select the most recent date.
I'm using MS SQL.
Can anyone help?
Try this using ISDATE and CONVERT:
SELECT MAX(CONVERT(DateTime, MaybeDate))
FROM (
SELECT MaybeDate
FROM MyTable
WHERE ISDATE(MaybeDate) = 1) T
You could also use MAX(CAST(MaybeDate AS DateTime)). I got in the (maybe bad?) habit of using CONVERT years ago and have stuck with it.
To do this without a conversion error:
select max(case when isdate(col) = 1 then cast(col as date) end) -- or use convert()
from . . .
The SQL statement does not specify the order of operations. So, even including a where clause in a subquery will not guarantee that only dates get converted. In fact, the SQL Server optimizer is "smart" enough to do the conversion when the data is brought in and then do the filtering afterwards.
The only operation that guarantees sequencing of operations is the case statement, and there are even exceptions to that.
Another solution would be using PATINDEX in WHERE clause.
SELECT PATINDEX('[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]', field_value)
Problem with this approach is you really are not sure if something is date (e.g. 99/99/9999 is not date).
And problem with IS_DATE is it depends on configuration (e.g. DATEFORMAT).
So, use an appropriate option.