I need to checking a column where numeric or not in SQL Server 2012.
This my case code.
CASE
WHEN ISNUMERIC(CUST_TELE) = 1
THEN CUST_TELE
ELSE NULL
END AS CUSTOMER_CONTACT_NO
But when the '78603D99' value is reached, it returns 1 which means SQL Server considered this string as numeric.
Why is that?
How to avoid this kind of issues?
Unfortunately, the ISNUMERIC() function in SQL Server has many quirks. It's not exactly buggy, but it rarely does what people expect it to when they first use it.
However, since you're using SQL Server 2012 you can use the TRY_PARSE() function which will do what you want.
This returns NULL:
SELECT TRY_PARSE('7860D399' AS int)
This returns 7860399
SELECT TRY_PARSE('7860399' AS int)
https://msdn.microsoft.com/en-us/library/hh213126.aspx
Obviously, this works for datatypes other than INT as well. You say you want to check that a value is numeric, but I think you mean INT.
Although try_convert() or try_parse() works for a built-in type, it might not do exactly what you want. For instance, it might allow decimal points, negative signs, and limit the length of digits.
Also, isnumeric() is going to recognize negative numbers, decimals, and exponential notation.
If you want to test a string only for digits, then you can use not like logic:
(CASE WHEN CUST_TELE NOT LIKE '%[^0-9]%'
THEN CUST_TELE
END) AS CUSTOMER_CONTACT_NO
This simply says that CUST_TELE contains no characters that are not digits.
Nothing substantive to add but a couple warnings.
1) ISNUMERIC() won't catch blanks but they will break numeric conversions.
2) If there is a single non-numeric character in the field and you use REPLACE to get rid of it you still need to handle the blank (usually with a CASE statement).
For instance if the field contains a single '-' character and you use this:
cast(REPLACE(myField, '-', '') as decimal(20,4)) myNumField
it will fail and you'll need to use something like this:
CASE WHEN myField IN ('','-') THEN NULL ELSE cast(REPLACE(myField, '-', '') as decimal(20,4)) END myNumField
Related
how can I convert to T-Sql this one?
IIf([ESSValue]<>0,Int([ESSValue]*100),"")
I think the following pretty much does what you want:
select coalesce(cast(EssValue * 100 as int), 0)
Here is the thinking. The comparison to zero is unimportant, because 0 times any value is going to be zero. The iif() returns an integer (I think) because the "then" argument is an integer; the empty string gets converted to zero.
I'm not 100% certain about the last statements with regard to MS Access, but that is how iif() works in SQL Server.
I should add. Although I don't approve of iif() for conditional expressions (because case is the standard and more powerful), SQL Server does support it. So you could write:
IIf([ESSValue]<>0, cast([ESSValue]*100 as int), '')
Note: As I mentioned earlier, the '' will be converted to 0.
CASE WHEN ESSValue <> 0
THEN CAST(ESSValue * 100 AS INT)
ELSE NULL
END as fieldname
For case expression the default is NULL if doesn't meet any condition, so you dont really need the ELSE condition
I am trying to compare two string using Sql query. for e.g In table A i have A123.45 and in table B i have A12345. this two string are same if i ignore decimal point so as a output i would want table A's value.
First, to avoid the XY problem, it's a little unclear to me why you'd want to do this in the first place - I'm not sure exactly why 123.45 should be equal to 12345. Definitely something to think about.
With that said, if you insist, you can do something like the following:
select case when replace(cast(floatingPointNumber as varchar(50)), '.', '') = cast(yourInteger as varchar(50)) then 1 else 0 end
from YourTable
Obviously, floatingPointNumber is a float and yourInteger is an integer.
I'm not sure what platform you're using since you didn't tag it but I wrote/tested this in SQL Server. You can do something similar in Oracle/MySQL if that's what you're using.
Basically, what this is doing is casting both the floating point number and the integer to strings, removing the decimal from the floating point number, and comparing them. If they're equal, it returns 1; otherwise it returns 0.
SQL0802 Data conversion or data mapping error
The fields not being CAST are decimals. The fields I am trying to CAST are strings.
I have tried different variations or CAST and CONVERT on this case expression. I'm fairly certain this syntax is correct. I am still getting the error though.
CASE WHEN cpssn=amssn THEN amfnam||amlnam
WHEN cpssn=CAST(maassn as DECIMAL(9)) THEN maafnm||maalnm
WHEN cpssn=CAST(mpssno as DECIMAL(9)) THEN mppfnm||mpplnm
END as Name
One brute force method uses translate():
(CASE WHEN cpssn = amssn THEN amfnam||amlnam
WHEN length(translate(massn, 'a0123456789', 'a')) > 0 THEN NULL
WHEN length(translate(mpssno, 'a0123456789', 'a')) > 0 THEN NULL
WHEN cpssn = CAST(maassn as DECIMAL(9)) THEN maafnm||maalnm
WHEN cpssn = CAST(mpssno as DECIMAL(9)) THEN mppfnm||mpplnm
END) as Name
Note: I am not intimately familiar with translate() in DB2. The above uses an Oracle convention for removing characters, because the third argument cannot be '' in Oracle. It should still work in DB2.
This should work by first guaranteeing that the only characters in the strings are digits. case is processed in sequential order, so the digit checks should be done before the conversion.
I have this possible values in a column
1
65
5 excellent
54
-1
-
.
If I use isnumeric with the last example I get 1, but when I try to convert to number I got an error. I want to use a try-catch in a function but I can't, how can I deal with this?
By the way, an even worse example is '-.', which isnumeric() considers to be valid.
My advice is to look for at least one digit in the value as well. Yucky, but:
isnumeric(val) and val like '%[0-9]%'
Note that isnumeric() also considers something in exponential notation to be valid. So '8e4' will test as positive. This may not be an issue for you, because it will convert to a valid value. Such matches have caused a problem for me in the past, so I tend to use something like:
val not like '%[^0-9.]%' and val not like '%.%.%' and val like '%[0-9]%'
That is, it only has decimal points and digits. And, it doesn't have two decimal points. But, it only works for positive values.
I think you are looking for something like this:
select case isnumeric('a') when 1 then convert(int,'a') else null end
Could you explain your goal? Something like this could be useful:
SELECT CASE ISNUMERIC(col)
WHEN 1 THEN CAST(col as float) -- or int, decimal, etc.
ELSE NULL -- Or 0, -9999, or whatever value you want to use as "exception" value
END
The TRY…CATCH construct cannot be used in a user-defined function.
http://msdn.microsoft.com/en-us/library/ms175976%28v=SQL.105%29.aspx
If you are working on SQL Server 2012, I recommend using TRY_CONVERT:
select TRY_CONVERT(int, '.') returns NULL instead of an error.
I'm selecting a value out of a table that can either be an integer or a nvarchar. It's stored as nvarchar. I want to conditionally call a function that will convert this value if it is an integer (that is, if it can be converted into an integer), otherwise I want to select the nvarchar with no conversion.
This is hitting a SQL Server 2005 database.
select case
when T.Value (is integer) then SomeConversionFunction(T.Value)
else T.Value
end as SomeAlias
from SomeTable T
Note that it is the "(is integer)" part that I'm having trouble with. Thanks in advance.
UPDATE
Check the comment on Ian's answer. It explains the why and the what a little better. Thanks to everyone for their thoughts.
select case
when ISNUMERIC(T.Value) then T.Value
else SomeConversionFunction(T.Value)
end as SomeAlias
Also, have you considered using the sql_variant data type?
The result set can only have one type associated with it for each column, you will get an error if the first row converts to an integer and there are strings that follow:
Msg 245, Level 16, State 1, Line 1
Conversion failed when converting the nvarchar value 'word' to data type int.
try this to see:
create table testing
(
strangevalue nvarchar(10)
)
insert into testing values (1)
insert into testing values ('word')
select * from testing
select
case
when ISNUMERIC(strangevalue)=1 THEN CONVERT(int,strangevalue)
ELSE strangevalue
END
FROM testing
best bet is to return two columns:
select
case
when ISNUMERIC(strangevalue)=1 THEN CONVERT(int,strangevalue)
ELSE NULL
END AS StrangvalueINT
,case
when ISNUMERIC(strangevalue)=1 THEN NULL
ELSE strangevalue
END AS StrangvalueString
FROM testing
or your application can test for numeric and do your special processing.
You can't have a column that is sometimes an integer and sometimes a string. Return the string and check it using int.TryParse() in the client code.
ISNUMERIC. However, this accepts +, - and decimals so more work is needed.
However, you can't have the columns as both datatypes in one go: you'll need 2 columns.
I'd suggest that you deal with this in your client or use an ISNUMERIC replacement
IsNumeric will get you part of the way there. You can then add some further code to check whether it is an integer
for example:
select top 10
case
when isnumeric(mycolumn) = 1 then
case
when convert(int, mycolumn) = mycolumn then
'integer'
else
'number but not an integer'
end
else
'not a number'
end
from mytable
To clarify some other answers, your SQL statement can't return different data types in one column (it looks like the other answers are saying you can't store different data types in one column - yours are all strign represenations).
Therefore, if you use ISNUMERIC or another function, the value will be cast as a string in the table that is returned anyway if there are other strigns being selected.
If you are selecting only one value then it could return a string or a number, however your front end code will need to be able to return the different data types.
Just to add to some of the other comments about not being able to return different data types in the same column... Database columns should know what datatype they are holding. If they don't then that should be a BIG red flag that you have a design problem somewhere, which almost guarantees future headaches (like this one).