Execute SQL Task -Full Result Set Datatype Mismatch Error - sql

Question

I am creating an SSIS package which has an execute SQL task and it passes result set variable to a for each loop container.
My Sql Query is:
Select distinct code from house where active=1 and campus='W'
I want the execute sql task to run this query and assign its results to a variable which is passed to a for each loop container which should loop through all the values in the result set.
But my execute sql task fails with error:
The type of the value (DBNull) being assigned to variable
"User::house" differs from the current variable type (String)
Now i have done my research and i have tried assigning the variable datatype Object but did not work. I tried using cast in my sql query and that also did not work.
Since my query returns multiple rows and one column, i am not sure how i can assign a datatype to the whole query?
Sample:
Code
AR
BN
CN

Answer 1

It sounds like you have a variety of issues in here.
Result Set
The first is in your Execute SQL Task and the need for agreement between the Result Set specification and the data type of the Variable(s) specified in the Result Set tab. If you specify Full Resultset, then the receiving object must be of type System::Object and you will only have 1 result set. The type of Connection Manager (ODBC/OLE/ADO) used will determine how you specify it but it's infinitely searchable on these fine forums.
The other two options are Single Row and XML. In 13 years of working with SSIS, I've never had cause to specify XML. That leaves us with Single Row. For a Single Row Result Set, you need to provide a variable for each column returned and it needs to be correctly typed.
To correct your issue, you need to declare a second variable. I usually call my rsObject (record set object) and then specify the data type as System.Object.
For Each Loop Container
Your For Each Loop Container will then be set with an Enumerator of "Foreach ADO Enumerator" and then the ADO object source variable will become "User::rsObject"
In the Variable Mappings, you'll specify your variable User::house to index 0.
Testing
Given a sample set of source source data, you can verify that you have your Execute SQL Task correctly assigning a result set to our object and the Foreach Loop Container is properly populating our variable.
SELECT DISTINCT
code
FROM
(
VALUES
('ABC', 1, 'w')
, ('BCD', 1, 'w')
, ('CDE', 0, 'w')
, ('DEF', 1, 'w')
, ('EFG', 1, 'x')
) house(code, active, campus)
WHERE
active = 1
AND campus = 'w';
If you change the value of campus from w to something that doesn't exist, like f then things will continue to work.
However, the error you're receiving can only be generated if the code is a NULL
Add one more entry to the VALUES collection like
, (NULL, 1, 'w')
and when the For Each Loop Container hits that value, you will encounter the error you indicate
The type of the value (DBNull) being assigned to variable "User::house" differs from the current variable type (String)
Now what?
SSIS variables cannot change their data type, unless they're of type Object (but that's not the solution here). The "problem" is that you cannot store a NULL value in an SSIS variable (unless it's of type object). Therefore you need to either exclude the rows that return a NULL (AND code IS NOT NULL) or you need to cast the NULL into sentinel/placeholder value as a substitute (SELECT DISTINCT ISNULL(code, '') AS code). If an empty string is a valid value, then you need to find something that isn't - "billinkcisthegreatestever10123432" is unlikely to exist in your set of codes but that might be a bit excessive.
Finally, think about renaming your SSIS variable from house to code. You might be able to keep things straight but some day you'll hand this code over to someone else for maintenance and you don't want to confuse them.
A picturesque answer https://stackoverflow.com/a/13976990/181965

Answer 2

the variable "User::house" is string , so , did you use it in result set?

Answer 3

you need declare son "object" var for result set
result set
then declare a string variable for every single Code from your result
For Each Loop Container
good luck