PHPで多次元配列から重複した値を削除するにはどうすればよいですか?

Array
(
[0] => Array
(
[0] => php
[1] => sql
)

[1] => Array
(
[0] => javascript
[1] => c
)

[2] => Array
(
[0] => php
[1] => sql
)

[3] => Array
(
[0] => c++
[1] => java
)

)

$myArray = Array(
          Array('php','sql'),
          Array('javascript','c'),
          Array('php','sql'),
          Array('c++','java')
        );

$myArray = array_map("unserialize", array_unique(array_map("serialize", $myArray)));

print_r($myArray);

Array
(
[0] => Array
(
[0] => php
[1] => sql
)

[1] => Array
(
[0] => javascript
[1] => c
)

[3] => Array
(
[0] => c++
[1] => java
)

)