Question

Say I have an array of strings in a php array called $foo with a few hundred entries, and I have a MySQL table ‘people’ that has a field named ‘name’ with a few thousand entries. What is an efficient way to find out which strings in $foo aren’t a ‘name’ in an entry in ‘people’ without submitting a query for every string in $foo?

So I want to find out what strings in $foo have not already been entered in ‘people.’

Note that it is clear that all of the data will have to be on one box at one point. The goal would be doing this at the same time minimizing the number of queries and the amount of php processing.

Answer 1

CREATE TEMPORARY TABLE PhpArray (name varchar(50));  -- you can probably do this more efficiently INSERT INTO PhpArray VALUES ($foo[0]), ($foo[1]), ...;  SELECT People.* FROM People  LEFT OUTER JOIN PhpArray USING (name) WHERE PhpArray.name IS NULL;