我想从标签表创建一个物化视图，然后在其上创建索引。但是，当我键入查询以创建此视图时，postgres弹出一个错误。
下面是我键入的查询，用于返回包含“Book”标签的所有顶点：

demo=# SELECT * FROM cypher ('demo', $$
demo$# MATCH (v:Book)
demo$# RETURN v
demo$# $$) as (vertex agtype);
                                                                vertex
---------------------------------------------------------------------------------------------------------------------------------------
 {"id": 1125899906842625, "label": "Book", "properties": {"title": "The Hobbit"}}::vertex
 {"id": 1125899906842626, "label": "Book", "properties": {"title": "SPQR: A History of Ancient Rome", "author": "Mary Beard"}}::vertex
(2 rows)

下面是我创建物化视图的方法：

demo=# CREATE MATERIALIZED VIEW book_view AS SELECT * FROM cypher ('demo', $$
MATCH (v:Book)
RETURN v.author, v.title
$$) as (author agtype, title agtype);

ERROR:  unhandled cypher(cstring) function call
DETAIL:  demo