AlterQuery  table_with_string_key (children 2)
 ExpressionList (children 1)
  AlterCommand MODIFY_COLUMN (children 1)
   ColumnDeclaration str_key (children 1)
    DataType LowCardinality (children 1)
     ExpressionList (children 1)
      DataType String
 Identifier table_with_string_key
