Query Single Record Source. You can invoke Query Builder by clicking on the button with the three dots to the right of the Record Source property. Lets break the code and analyze whats going on in inner query.
Open the form or report in Design view. If entireRow is true then it returns an array of the entire first row. By default querySingle returns the value of the first column returned by the query.
The event source is then joined to the process metadata table in the source query and made to return events later than the last run date.
The idea that I was thinking was to have two queries as the forms record source. When no persistence found this method will return a null value. When the subquery returns a single value the subquery is only evaluated once and then the value is returned to outer query to use. The event source is then joined to the process metadata table in the source query and made to return events later than the last run date.
