CreateQuery t_get_subcolumn (children 3)
 Identifier t_get_subcolumn
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration id (children 1)
    DataType UInt64
   ColumnDeclaration n (children 1)
    DataType Nested (children 1)
     ExpressionList (children 2)
      NameTypePair u (children 1)
       DataType UInt64
      NameTypePair s (children 1)
       DataType String
 Storage definition (children 2)
  Function MergeTree
  Identifier id
