How do I filter the records of one array by those that do not exist in another array?

Question

I have two result sets:

$array1 = (0=>'name1',1=>'name2');

and

$array2 = (0=>'name',1=>'name1',2=>'name2',3=>'name4');

I want to loop through array2 and eliminate any record that does exist in array1

For some reason I can't use this syntax:

select * where not in(select ....)

Answer 1

For a SQL select which has multiple fields for the key, you can use the following syntax...

SELECT *
FROM CompletedTasks
WHERE (userID, taskID) NOT IN
      ( SELECT userID, taskID
        FROM PlannedTasks
      ) ;

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