Error using two lookup output in a if statement in foreach loop

Question

I am trying to loop through the output of one of the two Lookup activity in a ForEach loop based on a condition. For this I am using a if statement as given below:

@if(equals(variables('PreviousExecutionFlag'),0),activity('Control Table for all tables').output.value,activity('Lookup2').output.value)
																						

I am getting below error:

"The expression 'length(if(equals(variables('PreviousExecutionFlag'),0),activity('Control Table for all tables').output.value,activity('Lookup2').output.value)

)' cannot be evaluated because property 'output' cannot be selected."

I have used

@activity('Lookup2').output.value

in a for each loop and it works fine but when using in a if condition, it doesn't work.

Please help .

Answer 1

Hi Amit Trivedi ,

Thankyou for using Microsoft Q&A platform and thanks for posting your question here.

As per my understanding you are trying to use if expression in ADF pipeline to check if value of a variable is equal to 0 or not. In case if it's equal to 0, then return the output value from first lookup activity else return the output value from second lookup activity.

First of all, the expression which you have shared doesn't have length property , however, in the error message , we can see the expression is supposed to return the length of the output array after evaluating the if condition. Could you please cross check that and remove length from the expression. Also, if possible kindly share the screenshot of your pipeline.

I would suggest you to create an additional variable of type 'array' and use a set variable activity before foreach and store the output array of 'if expression ' into that variable and then in the foreach point to that variable as item.

Hope it helps. Kindly accept the answer by clicking `Accept answer

Answer 2

Hi Amit Trivedi ,

Thankyou for using Microsoft Q&A platform and thanks for posting your question here.

As per my understanding you are trying to use if expression in ADF pipeline to check if value of a variable is equal to 0 or not. In case if it's equal to 0, then return the output value from first lookup activity else return the output value from second lookup activity.

First of all, the expression which you have shared doesn't have length property , however, in the error message , we can see the expression is supposed to return the length of the output array after evaluating the if condition. Could you please cross check that and remove length from the expression. Also, if possible kindly share the screenshot of your pipeline.

I would suggest you to create an additional variable of type 'array' and use a set variable activity before foreach and store the output array of 'if expression ' into that variable and then in the foreach point to that variable as item.

Hope it helps. Kindly accept the answer by clicking Accept answer button. Thankyou

Answer 3

Thanks for your reply.

I forgot to mention, I am not using length() anywhere in my pipeline but still it is showing in the error.