SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function arrayRemove (children 1)
     ExpressionList (children 2)
      Function CAST (children 1)
       ExpressionList (children 2)
        Literal Array_[\'a\', NULL, \'b\']
        Literal \'Array(LowCardinality(Nullable(String)))\'
      Literal \'a\'
