Column problem with a SSIS package

[kxramse]

I have a job that builds a flat file. It has a SQL statement in it that created a column like this in a flat file.
select
campaigntrackingcode=NULL,
column2
from stmrecieved

then that column, part of a larger select statement was sent to a flat file.

I have since decided what to put in that value and changed it to something like this
select
stmreceived.campaigntrackingcode,
column2
from stmrecieved


When I run my SSIS Package I get an error:

 [Source - Query [1]] Error: There was an error with output column "CampaignTrackingCode" (35) on output "OLE DB Source Output" (11). The column status returned was: "The value could not be converted because of a potential loss of data.".

When I change it back to NULL, its gone. Its as though there is some sort of assignment of the type of column somewhere that I can't find and that doesn't like being reassigned a data type now that its being sent string data in the field.

Where can I find my problem?

 

[kxramse]

I found my answer. You have to go to the Data flow tab. Then right click and pick show advanced editor, then input and output properties, then find the output property and change it to the new data type. I swear there were 10 places to look!