php 以下格式的array多维数组怎么循环取值?

数组格式如下:怎么循环获取每组的AA值或BB值或CC的值

又或者把以下格式的多维数组合并到一个数组里,即是把D,C,B数组合并到A数组里

Array
  ([0] => Array(
     [A] => Array
       (
         [AA] => 1
         [BB] => 2
         [CC] => 4
       )

     [B] => Array
       (
         [AA] => 3
         [BB] => 5
         [CC] => 7
       )

     [C] => Array
       (
         [AA] => 11
         [BB] => 22
         [CC] => 44
       )

     [D] => Array
       (
         [AA] => 00
         [BB] => 66
         [CC] => 88
       )

                )
  )

两个foreach呗