Today is Monday let us start this week with interesting puzzle. Yesterday I had also posted quick question here: SQL SERVER – T-SQL Scripts to Find Maximum between Two Numbers
Run following code:
SELECT SUM(data)
FROM (SELECT NULL AS DATA) t
It will throw following error.
Msg 8117, Level 16, State 1, Line 1
Operand data type void type is invalid for sum operator.
I can easily fix if I use ISNULL Function as displayed following.
SELECT SUM(data)
FROM (SELECT ISNULL(NULL,0) AS DATA) t
Above script will not throw an error. However, there is one more method how this can be fixed.
Can you come up with another method which will not generate error?
Reference: Pinal Dave (http://blog.SQLAuthority.com)
SELECT SUM(isnull(data,0))
FROM (SELECT NULL AS DATA) t
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
OR
SELECT SUM(Coalesce(data,0))
FROM (SELECT NULL AS DATA) t
Cheers
Shekhar Teke
I think your isnull(null,0) is cheating, because your really doing a SELECT SUM(data) FROM (SELECT 0 AS DATA) t, which works without a problem.
Select SUM(null) also fails, which gets us closer to the root cause – SQL Server can’t determine the data type of NULL.
If we cast null to int using SELECT SUM(data) FROM (SELECT cast(NULL as int) AS DATA) t , we get rid of the error, however the result is now NULL.
Another method that will return NULL is: SELECT SUM(data) FROM (SELECT 0 + NULL AS DATA)
I guess the answer really depends on how you define “fixed”.
We can also move the ISNULL into the sum eg, SELECT SUM(isnull(data,0)) FROM (SELECT NULL AS DATA) t.
Other solutions would be isNull replacements, eg, CASE, COALESCE, which both ‘fix’ the problem, and return your original value of 0.
Dave
SELECT SUM(data)
FROM (SELECT convert(int, NULL) AS DATA) t
Hi Pinal,
We can use COALESCE to fix this, Please see below query
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
Regards
Arunraj Chandrasekaran
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
SELECT SUM(data)
FROM (SELECT COALESCE(null,0) AS DATA) t
SELECT SUM(ISNULL(data,0))
FROM (SELECT NULL AS DATA) t
GO
SELECT SUM(COALESCE(data,0))
FROM (SELECT NULL AS DATA) t
GO
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
SELECT SUM(data)
FROM (SELECT CASE WHEN NULL is NULL then 0 END AS DATA) t
Similarly we can handle the NULL as
SELECT SUM(isnull(data,0))
FROM (SELECT NULL AS DATA) t
The Following could be the other alternatives -
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
SELECT SUM(ISNULL(data,0))
FROM (SELECT NULL AS DATA) t
SELECT SUM(COALESCE(data,0))
FROM (SELECT NULL AS DATA) t
Hi pinal,
I think we can use COALESCE like
select SUM(data)
from (select COALESCE(null,0) as data) t
SUM can be used with numeric columns only. Null values are ignored.
SELECT SUM(isnull(data,0))
FROM (SELECT NULL AS DATA) t
oR
SELECT SUM(cast(data as Int))
FROM (SELECT NULL AS DATA) t
HI Pinal
We can use below also
SELECT SUM(data*1)
FROM (SELECT NULL AS DATA) t
Hi Pinal,
Can we use this method :
SELECT SUM(data)
FROM (SELECT Cast(NULL as int) AS DATA) t
Hello,
I believe that you just need to convert the null void to a value of type
tinyint
smallint
int
bigint
decimal category (p, s)
money and smallmoney category
float and real category
using an explicit cast (or convert)
or
do something like isnull coalesce when an implicit cast is applied.
SELECT SUM(data)
FROM (SELECT NULL AS DATA union all SELECT 0 AS DATA) t
select cast((SELECT NULL AS DATA FOR XML RAW, ELEMENTS) as XML).query(‘sum(/row/DATA)’)
Hi pinal,
I think we can use COALESCE like
select SUM(data)
from (select COALESCE(null,0) as data) t
OR
SELECT SUM(isnull(data,0))
FROM (SELECT NULL AS DATA) t
SELECT SUM(CASE WHEN Data IS NULL THEN 0 ELSE DATA END)
FROM (SELECT NULL AS DATA) t
This is same as using isnull or coalesce function
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
David Ames is correct, and your “solution” just hard-codes the data, rather than the function, so I don’t like that. This “puzzle” does, however, expose a bug (or, at least, an anomaly) in SQL Server, where aggregate functions, other than COUNT, supposedly ignore NULLs. If that’s correct (and it’s in BOL), then his example:
SELECT SUM(data)
FROM (SELECT CAST(NULL AS int) data) AS t;
should evaluate to 0 and not NULL.
SELECT SUM(data)
FROM (SELECT convert(int,NULL) AS DATA) t
Its COALESCE!!
SELECT MAX(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
or
SELECT SUM(data)
FROM (SELECT COALESCE(NULL,0) AS DATA) t
SELECT SUM(data)
FROM (SELECT isnumeric(null) AS DATA) t
SELECT SUM(data)
FROM (SELECT coalesce(NULL,0) AS DATA) t
[...] Comments « SQL SERVER – Puzzle Involving NULL – Resolve – Error – Operand data type voi… [...]
perfect Alex, by default its taking as char\varchar, so we’re getting error. by converting in to numeric datatype, will resolve the error.
SELECT SUM(data)
FROM (SELECT convert(varchar,NULL) AS DATA) t
Go
SELECT SUM(data)
FROM (SELECT convert(numeric ,NULL) AS DATA) t
Use This
Select Case When Sum(Data) is Null then 0 else Sum(Data) end as Data from t.
it will gve u exact data and not throw any typem of error.Try this.
SELECT SUM(isnull(DATA,0))
FROM (SELECT NULL AS DATA) t
SELECT SUM(COALESCE(DATA,0))
FROM (SELECT NULL AS DATA) t
SELECT SUM((CASE WHEN DATA IS NULL THEN 0 ELSE DATA END))
FROM (SELECT NULL AS DATA) t
let I have a table name x which have two cloumn date1 as nvarchar(10) and date2 as (varchar(30)).the format of storing data is like this date2=Aug 6 2010 3:32PM and date1=12112010;
But not I wane to select the difference between these two dates.
So please reply quickly…..It is an urgent
let I have a table name x which have two cloumn date1 as nvarchar(10) and date2 as (varchar(30)).the format of storing data is like this date2=Aug 6 2010 3:32PM and date1=12112010;
But now I want to select the difference between these two dates.
So please reply quickly…..It is an urgent
SELECT SUM(data)
FROM (SELECT ” AS DATA) t