AlterQuery  mt (children 2)
 ExpressionList (children 1)
  AlterCommand UPDATE (children 2)
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier y
     Literal UInt64_1
   ExpressionList (children 1)
    Assignment x (children 1)
     Literal \'Goodbye\'
 Identifier mt