It is good to have an extraction operator for getting sub strings easily in datastage. But still it also has an ugly face.. at certain cases this will fail your job and if you dig you logs you will be ended with nothing.
So when this creates the problem ?
If you are using any arithmetic operators in your extraction parameter then you need to take care about the final results of your arithmatic operations. This can be better explained with the following example,
consider we are having following expression DSLink3.Amount[vA,vB-vC]. Here we need to make sure that the expression will never return a negative value. Means vB-vC should always be positive value. Else you will get APTCombinedOperator error. It will not show the stage which trowed the error also.
So wrap up the above extraction with an if kind of checking like,
If (vB-vC) > 0 Then
DSLink3.Amount[vA,vB-vC]
Else
”
Hope this helps to you make your job error free.