Is there a way to query all tasks (1) which have key value ok and (2) whose goals have field value yes? And the second column would be only the goals with yes. The output would be:
And what if the restraining information for the goals are not a particular field value, but the folder they are contained, or the string they start with?
WHERE evaluates the expression and looks for something that looks true or false. In the case of filter(), if the returned list has any values then it considers it a true result; if the list is empty it considers it a false result.
Because of this, the WHERE clause will filter out any pages where no backlinked pages have field=yes.