CreateQuery test_hierarchy_source_table (children 3)
 Identifier test_hierarchy_source_table
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration id (children 1)
    DataType UInt64
   ColumnDeclaration parent_id (children 1)
    DataType UInt64
 Storage definition (children 2)
  Function MergeTree
  Identifier id
