AlterQuery  t_materialize_column (children 2)
 ExpressionList (children 1)
  AlterCommand ADD_COLUMN (children 1)
   ColumnDeclaration s (children 2)
    DataType LowCardinality (children 1)
     ExpressionList (children 1)
      DataType String
    Function toString (children 1)
     ExpressionList (children 1)
      Identifier i
 Identifier t_materialize_column