Remove duplicate items from an array [duplicate]

Question

I use the line of code below to loop through a table in my database:

$items_thread = $connection -> fetch_all($sql); 

And if I print the array out:

print_r($items_thread); 

I will get this:

Array (     [0] => Array         (             [RecipientID] => 3             [RecipientScreenname] => Tom L             [RecipientFirstname] => Thomas             [RecipientEmail] => [email protected]         )      [1] => Array         (             [RecipientID] => 3             [RecipientScreenname] => Tom L             [RecipientFirstname] => Thomas             [RecipientEmail] => [email protected]         )      [2] => Array         (             [RecipientID] => 1             [RecipientScreenname] => Lau T             [RecipientFirstname] => TK             [RecipientEmail] => [email protected]         )  ) 

But I want to get rid of the duplicate items in the array, so I use array_unique

print_r(array_unique($items_thread)); 

I get the weird result below which is not quite I am looking for:

Array (     [0] => Array         (             [RecipientID] => 3             [RecipientScreenname] => Tom L             [RecipientFirstname] => Thomas             [RecipientEmail] => [email protected]         )  ) 

Ideally, I think it should return this:

Array (     [0] => Array         (             [RecipientID] => 3             [RecipientScreenname] => Tom L             [RecipientFirstname] => Thomas             [RecipientEmail] => [email protected]         )      [1] => Array         (             [RecipientID] => 1             [RecipientScreenname] => Lau T             [RecipientFirstname] => TK             [RecipientEmail] => [email protected]         )  ) 

What shall I do to get it right? Have I used the wrong PHP syntax/default function?

Answer 1

The array_unique function will do this for you. You just needed to add the SORT_REGULAR flag:

$items_thread = array_unique($items_thread, SORT_REGULAR); 

However, as bren suggests, you should do this in SQL if possible.

Answer 2

You'd be much better off filtering out the duplicates in the SQL query. add a constraint which fetches a UNIQUE recipientID