我有一个关于从Postgresql提取表名的问题

Question

我想问一下使用Python 3.X从Postgresql查询中提取表名的问题。

这是我的条件。

1.Python 3.X   包装   sqlparse 2.PostgreSQL

这是我的sql代码。

$postgresql

With 
a as (
  select x,y
  from g
)

select x, y,z
from      b
left join a  on b.id = a.id

我想通过Python3.X使用sqlparse从上述查询中获取结果。

#table name : g, b

如何改善我的以下代码？

$Python3

import sqlparse
from sqlparse.sql import Where, Comparison, Parenthesis, Identifier


class RecursiveTokenParser(object):
 def __init__(self, query):
    self.query = query
    self.names = []

 def get_table_names(self):
     elements = sqlparse.parse(self.query)

     for token in elements[0].tokens:

         if isinstance(token, Identifier):
             self.identifier(token)
         elif isinstance(token, Parenthesis):
             self.parenthesis(token)

         elif isinstance(token, Where):
             self.where(token)

     return [str(name) for name in self.names]

 def where(self, token):

    for subtoken in token.tokens:
        if isinstance(subtoken, Comparison):
           self.comparison(subtoken)

 def comparison(self, token):
    for subtoken in token.tokens:
        if isinstance(subtoken, Parenthesis):
           self.parenthesis(subtoken)

 def parenthesis(self, token):

    for subtoken in token.tokens:
        if isinstance(subtoken, Identifier):
           self.identifier(subtoken)
        elif isinstance(subtoken, Parenthesis):
           self.parenthesis(subtoken)

 def identifier(self, token):
     self.names.append(token)

 def get_query(self):  
    return self.query


sql = """

     WITH a as
     (
      SELECT 
        id, x, y
      FROM d
     )

     SELECT 
         x,y, z
     FROM e 
     left join a c
     ON a.id = e.id 
     """
t = RecursiveTokenParser(sql)

print(t.get_query())
print(t.get_table_names())

结果：['a as \ n（\ n SELECT \ n id，x，y \ n FROM d \ n）'，'e'，'a c']