PS Query: How to use one prompt to let user to input the list of IDs

For now,

I am using expression PATINDEX('%,'+  A.EMPLID +',%', :1)

Criteria: PATINDEX('%,'+  A.EMPLID +',%', :1) greater than 0

use prompt (:1) to let user to enter a list of IDs in prompt. some examples of My list ids (more than 100) will look like", 1234567,2234567,3234567,9845712,54545241…."

It went to success if I limit the length less than 250 in prompt(:1) properties.

It will not run to success if I input the length more than 500 in prompt properties.

Any other suggestions and insights on how can I improve my ps query will be appreciated.

Kind regard,

Mel