AlterQuery  alter_ttl (children 2)
 ExpressionList (children 1)
  AlterCommand MODIFY_COLUMN (children 1)
   ColumnDeclaration s (children 2)
    DataType String
    Function toDate (children 1)
     ExpressionList (children 1)
      Literal \'2020-01-01\'
 Identifier alter_ttl