Array diff is only posible if an array is included in the other array?
Example :

A = 2,5,8,9
B = 2,5,12

Using array_diff, is the result in this case 8,9 ? 

I want to eliminate B from A only if B is included in A .
Array diff is only posible if an array is included in the other array?
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Example :

A = 2,5,8,9
B = 2,5,12

Using array_diff, is the result in this case 8,9 ? 

I want to eliminate B from A only if B is included in A .