How can I use ISNUMERIC() function with sql_variant datatype?
This following code doesn't work
DECLARE #x sql_variant
SET #x = 3
IF ISNUMERIC(#x) = 1
SELECT 'Numeric'
ELSE
SELECT ' NOT'
Error :
Msg 8116, Level 16, State 1, Line 4
Argument data type sql_variant is invalid for argument 1 of isnumeric function.
But this works
IF ISNUMERIC(CAST(#x AS INT)) = 1
is there is any way of making this happened with out CAST()
Haven't found any thing useful on google regarding this issue thanks , I'm using
SQL Server 2008 R2
If you want to know if the underlying datatype is numeric, you can use SQL_Variant_Property to find out;
DECLARE #x sql_variant
SET #x = 3.2
SELECT CASE
WHEN SQL_Variant_Property(#x, 'Precision') = 0
THEN 'NO'
ELSE 'YES'
END
Casting to int doesn't really make sense. Your conversion will fail (when something else than an integer appears) and you'll get an error.
You can, however, cast to nvarchar(max) - this should always work and your ISNUMERIC function will behave as expected
Related
I have a simple SQL CASE statement that I am trying to interpret the datatype of a variable and then converting it to said format. I have the following sample:
DECLARE #P1 varchar(10) = '2';
SELECT CASE 1
WHEN ISNUMERIC(#P1) THEN (CAST(#P1 AS INT))
WHEN ISDATE(#P1) THEN (CAST(#P1 AS DateTime))
ELSE 'N' END AS Test2P1
I would expect it to return an integer value of 2. However, this is what I get.
Test2P1
1900-01-03 00:00:00.000
However, if I modify the code to just display a character instead of CASTING the variable, I get a different result:
DECLARE #P1 varchar(10) = '2';
SELECT CASE 1
WHEN ISNUMERIC(#P1) THEN 'I'
WHEN ISDATE(#P1) THEN 'D'
ELSE 'N' END AS Test2P1
Then I get a result of: I
Taking this experiment one step further, if I leave the first test returning an 'I' but casting the date, then I get an error:
DECLARE #P1 varchar(10) = '2';
SELECT CASE 1
WHEN ISNUMERIC(#P1) THEN 'I'
WHEN ISDATE(#P1) THEN (CAST(#P1 AS DateTime))
ELSE 'N' END AS Test2P1
Msg 241, Level 16, State 1, Line 3
Conversion failed when converting date and/or time from character string.
It appears that SQL is evaluating multiple instances of THEN statements. However, the ISDATE expression does NOT return true. I am stumped.
In my research, I came across this article [SQL Performance] (https://sqlperformance.com/2014/06/t-sql-queries/dirty-secrets-of-the-case-expression) What he is saying in this article makes complete sense. But I do not see where it applies in this situation as I am never changing the value of the variable.
I have also wrapped my CASE statement in COALESCE(), but it does not appear to help. I wouldn't have expected it to, but I found multiple articles referencing this as a solution to similar problems. This seems like a very simple CASE statement, but I do not know where I am going wrong. Any help is greatly appreciated.
DateTime has a higher datatype precedence in SQL Server than INT does, so your whole CASE is getting cast as DATETIME. You can only return data of a single datatype in one column, thus the need for datatype precedence.
Here is the MSDN article showing precedence.
Although I can't think of a good reason to do this, you could force the case expression to return sql_variant, which can store multiple different types, eg:
DECLARE #P1 varchar(10) = '2';
SELECT CASE 1
when 0 then cast(null as sql_variant)
WHEN ISNUMERIC(#P1) THEN (CAST(#P1 AS INT))
WHEN ISDATE(#P1) THEN (CAST(#P1 AS DateTime))
ELSE 'N' END AS Test2P1
I'm getting the "conversion" error in a SQL Select query.
The error is:
Msg 248, Level 16, State 1, Line 6
The conversion of the nvarchar value '7000952682' overflowed an int column.
Problem is, there are no int columns in my table!
Here is the table structure:
Here is the query:
If I set the value of #SU to NULL, then it does return all rows as expected. When the value is set to the string value of '7000952682' I get the error.
Why is SQL Server trying to convert the nvarchar value to an int?
All branches of a CASE expression have to have the same type. In this case (no pun intended), it looks like SQL Server is using an integer type and doing an implicit cast of SU to integer. The problem is that the max value for an integer in SQL Server is roughly 2.1 billion, and the example you gave is using the value 7000952682, hence the overflow.
You have two options here. You could make everything varchar:
CASE WHEN #SU IS NULL OR #SU = '' THEN '1' ELSE [SU] END
Or, you could make everything numeric, using a type that won't overflow, e.g.
CASE WHEN #SU IS NULL OR #SU = ''
THEN CAST(1 AS numeric(20, 6))
ELSE CAST([SU] AS numeric(20, 6)) END
As a side note, you could write the first part of your CASE expression more succinctly using COALESCE:
CASE WHEN COALESCE(#SU, '') = '' THEN '1' ELSE [SU] END
Don't use case in the where clause. The logic is more simply and accurately expressed as:
where (#su is null or #su = '' or #su = su)
Consider the following numbers.
7870.2
8220.0
I need to remove decimal points if the value ends with .0. If it ends with .2 then it should keep the value as it is.
I have used ceiling but it removes all the values after decimal.
How can I write a select query in which I can add some condition for this?
Generally speaking you should not do this in your dB. This is an app or reporting side operation. The dB is made to store and query information. It is not made to format/string manipulate information.
use right within a case statement and:
DECLARE #val decimal(5,1)
SET #val = 7870.0
Select
Case
When right(#val,1)<> '0' then
cast(#val as varchar)
else
cast(cast(#val as int) as varchar)
End
output: 7870
EDIT: I could write :
Case
When right(#val,1)<> '0' then
#val
else
cast(#val as int) -- or floor(#val)
End
but because return type of case statement is the highest precedence type from the set of given types, so the output for second version is: 7870.0 not 7870, that's why I convert it to i.e varchar in when clauses, and it can be converted outside of case statement, I mean cast ((case when...then...else... end) as datatype)
Cast the number as a float, using float(24) to increase precision:
DECLARE #t table(number decimal(10,1))
INSERT #t values(7870.2),(8220.0)
SELECT cast(number as float(24))
FROM #t
Result:
7870,2
8220
Here below goes a sample:
declare #1 decimal(4,3)
select #1 = 2.9
select case when SUBSTRING (PARSENAME(#1,1), 1, 1) = 0 then FLOOR(#1) else #1 end
Change the #1 in the select statement with your database field name.
sqlfiddle
The solution seems to be simple:
SELECT CONVERT (FLOAT, PAYLOAD)
I'm encountering an error on the item below and I don't understand why. Can anyone shed some light on it for me?
CREATE FUNCTION dbo.fn_AcMonthOrder
(
#Month varchar(100)
)
RETURNS INT
AS
BEGIN
DECLARE #MonthOrder Int
SET #MonthOrder =
(CASE
WHEN #Month IN ('Aug','August',8) THEN 1
WHEN #Month IN ('Sep','September',9) THEN 2
WHEN#Month IN ('Oct','October',10) THEN 3
...
ELSE 0 END)
RETURN #MonthOrder
END
If I attempt to call this function then it works fine for an integer, but not for the varchars. I.e. PRINT #dbo.fn_AcMonthOrder(8) will return 1 as expected, but PRINT #dbo.fn_AcMonthOrder('Aug') Or PRINT #dbo.fn_AcMonthOrder('August') returns the following error:
Msg 245, Level 16, State 1, Line 1
Conversion failed when converting the varchar value 'Aug' to data type int.
When you use different data types in an expression, SQL Server follows data type precedence. In this case:
8 IN ('Aug','August', 8)
You're mixing int with varchar. Since int has higher precedence, it will convert the varchar to int. The reason this particular case does not throw an error might be optimization. This does throw an error:
8 IN ('Aug','August',10)
And this does not throw an error:
'Aug' IN ('Aug','August',8)
But this throws an error again:
'Sept' IN ('Aug','August',8)
This confirms that the optimizer first compares the elements that do not require conversion. It only raises an error when it gets to the elements it cannot convert.
At the end of the day, the best solution is to make sure all data types are the same. In your case, you could just list the numbers as a string:
WHEN #Month IN ('Aug','August','8') THEN 1
^^^^^
All the elements in the IN-list have to be of a type where implicit conversion is possible. You cannot convert a varchar value to an integer one, but the other way round. So try this statement.
CREATE FUNCTION dbo.fn_AcMonthOrder
(
#Month varchar(100)
)
RETURNS INT AS
BEGIN
DECLARE #MonthOrder Int
SET #MonthOrder =
(CASE
WHEN #Month IN ('Aug','August','8') THEN 1
WHEN #Month IN ('Sep','September','9') THEN 2
WHEN#Month IN ('Oct','October','10') THEN 3
ELSE 0
END)
RETURN #MonthOrder
END
When you use IN clause you should use one DataType now your are using 'Aug' near 8, and it assumes that it should convert 'aug',... to int it is incorrect.
you can write it in this way (Do it for all you Case Whens)
WHEN #Month IN ('Aug','August','8') THEN 1
.....
WHEN #Month IN ('Aug','August','8') THEN 1
WHEN #Month IN ('Sep','September','9') THEN 2
WHEN#Month IN ('Oct','October','10') THEN 3
Enclose in single quotes month values in numbers eg change 8 to '8' .
This is because #Month is of VARCHAR() datatype and IN() clause requires values inside it must have compatible datatype conversion amongst them.
The reserve column is a varchar, to perform sums on it I want to cast it to a deciaml.
But the SQL below gives me an error
select
cast(Reserve as decimal)
from MyReserves
Error converting data type varchar to numeric.
I added the isnumeric and not null to try and avoid this error but it still persists, any ideas why?
select
cast(Reserve as decimal)
from MyReserves
where isnumeric(Reserve ) = 1
and MyReserves is not null
See here: CAST and IsNumeric
Try this:
WHERE IsNumeric(Reserve + '.0e0') = 1 AND reserve IS NOT NULL
UPDATE
Default of decimal is (18,0), so
declare #i nvarchar(100)='12121212121211212122121'--length is>18
SELECT ISNUMERIC(#i) --gives 1
SELECT CAST(#i as decimal)--throws an error
Gosh, nobody seems to have explained this correctly. SQL is a descriptive language. It does not specify the order of operations.
The problem that you are (well, were) having is that the where does not do the filtering before the conversion takes place. Order of operations, though, is guaranteed for a case statement. So, the following will work:
select cast(case when isnumeric(Reserve) = 1 then Reserve end as decimal)
from MyReserves
where isnumeric(Reserve ) = 1 and MyReserves is not null
The issue has nothing to do with the particular numeric format you are converting to or with the isnumeric() function. It is simply that the ordering of operations is not guaranteed.
It seems that isnumeric has some Problems:
http://www.sqlhacks.com/Retrieve/Isnumeric-problems
(via internet archive)
According to that Link you can solve it like that:
select
cast(Reserve as decimal)
from MyReserves
where MyReserves is not null
and MyReserves * 1 = MyReserves
Use try_cast (sql 2012)
select
try_cast(Reserve as decimal)
from MyReserves
IsNumeric is a problem child -- SQL 2012 and later has TRY_CAST and TRY_CONVERT
If you're on an earlier version then you can write a function that'll convert to a decimal (or NULL if it won't convert). This uses the XML conversion functions that don't throw errors when the number won't fit ;)
-- Create function to convert a varchar to a decimal (returns null if it fails)
IF EXISTS( SELECT * FROM sys.objects WHERE object_id = OBJECT_ID( N'[dbo].[ToDecimal]' ) AND type IN( N'FN',N'IF',N'TF',N'FS',N'FT' ))
DROP FUNCTION [dbo].[ToDecimal];
GO
CREATE FUNCTION ToDecimal
(
#Value VARCHAR(MAX)
)
RETURNS DECIMAL(18,8)
AS
BEGIN
-- Uses XML/XPath to convert #Value to Decimal because it returns NULL it doesn't cast correctly
DECLARE #ValueAsXml XML
SELECT #ValueAsXml = Col FROM (SELECT (SELECT #Value as Value FOR XMl RAW, ELEMENTS) AS Col) AS test
DECLARE #Result DECIMAL(38,10)
-- XML/XPath will return NULL if the VARCHAR can't be converted to a DECIMAL(38,10)
SET #Result = #ValueAsXml.value('(/row/Value)[1] cast as xs:decimal?', 'DECIMAL(38,10)')
RETURN CASE -- Check if the number is within the range for a DECIMAL(18,8)
WHEN #Result >= -999999999999999999.99999999 AND #Result <= 999999999999999999.99999999
THEN CONVERT(DECIMAL(18,8),#Result)
ELSE
NULL
END
END
Then just change your query to:
select dbo.ToDecimal(Reserve) from MyReserves
isnumeric is not 100% reliable in SQL - see this question Why does ISNUMERIC('.') return 1?
I would guess that you have value in the reserve column that passes the isnumeric test but will not cast to decimal.
Just a heads up on isnumeric; if the string contains some numbers and an 'E' followed by some numbers, this is viewed as an exponent. Example, select isnumeric('123E0') returns 1.
I had this same problem and it turned out to be scientific notation such as '1.72918E-13' To find this just do where Reserve LIKE '%E%'. Try bypassing these and see if it works. You'll have to write code to convert these to something usable or reformat your source file so it doesn't store any numbers using scientific notation.
IsNumeric is possibly not ideal in your scenario as from the highlighted Note on this MSDN page it says "ISNUMERIC returns 1 for some characters that are not numbers, such as plus (+), minus (-), and valid currency symbols such as the dollar sign ($)."
Also there is a nice article here which further discusses ISNUMERIC.
Try (for example):
select
cast(Reserve as decimal(10,2))
from MyReserves
Numeric/Decimal generally want a precision an scale.
I am also facing this issue and I solved by below method. I am sharing this because it may helpful to some one.
declare #g varchar (50)
set #g=char(10)
select isnumeric(#g),#g, isnumeric(replace(replace(#g,char(13),char(10)),char(10),''))