Question

我有一个数据集，其中一些空值我想更新以读取缺失值而不是空值

我浏览了所有论坛和文档，但似乎找不到答复

from pandasql import sqldf

pysqldf = lambda q: sqldf(q, globals())

Updated_table= pysqldf("update practice_names set Region = 'test'       where Region is null;")

可悲的是，我得到了这个错误日志

--------------------------------------------------------------------------
OperationalError                          Traceback (most recent call last)
~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in _execute_context(self, dialect, constructor, statement, parameters, *args)
   1192                         parameters,
-> 1193                         context)
   1194         except BaseException as e:

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/default.py in do_execute(self, cursor, statement, parameters, context)
    508     def do_execute(self, cursor, statement, parameters, context=None):
--> 509         cursor.execute(statement, parameters)
    510 

OperationalError: no such table: practice_names

The above exception was the direct cause of the following exception:

OperationalError                          Traceback (most recent call last)
~/anaconda3/lib/python3.7/site-packages/pandasql/sqldf.py in __call__(self, query, env)
     60             try:
---> 61                 result = read_sql(query, conn)
     62             except DatabaseError as ex:

~/anaconda3/lib/python3.7/site-packages/pandas/io/sql.py in read_sql(sql, con, index_col, coerce_float, params, parse_dates, columns, chunksize)
    396             coerce_float=coerce_float, parse_dates=parse_dates,
--> 397             chunksize=chunksize)
    398 

~/anaconda3/lib/python3.7/site-packages/pandas/io/sql.py in read_query(self, sql, index_col, coerce_float, parse_dates, params, chunksize)
   1062 
-> 1063         result = self.execute(*args)
   1064         columns = result.keys()

~/anaconda3/lib/python3.7/site-packages/pandas/io/sql.py in execute(self, *args, **kwargs)
    953         """Simple passthrough to SQLAlchemy connectable"""
--> 954         return self.connectable.execute(*args, **kwargs)
    955 

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in execute(self, object, *multiparams, **params)
    941         if isinstance(object, util.string_types[0]):
--> 942             return self._execute_text(object, multiparams, params)
    943         try:

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in _execute_text(self, statement, multiparams, params)
   1103             parameters,
-> 1104             statement, parameters
   1105         )

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in _execute_context(self, dialect, constructor, statement, parameters, *args)
   1199                 cursor,
-> 1200                 context)
   1201 

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in _handle_dbapi_exception(self, e, statement, parameters, cursor, context)
   1412                     sqlalchemy_exception,
-> 1413                     exc_info
   1414                 )

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/util/compat.py in raise_from_cause(exception, exc_info)
    264     cause = exc_value if exc_value is not exception else None
--> 265     reraise(type(exception), exception, tb=exc_tb, cause=cause)
    266 

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/util/compat.py in reraise(tp, value, tb, cause)
    247         if value.__traceback__ is not tb:
--> 248             raise value.with_traceback(tb)
    249         raise value

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/base.py in _execute_context(self, dialect, constructor, statement, parameters, *args)
   1192                         parameters,
-> 1193                         context)
   1194         except BaseException as e:

~/anaconda3/lib/python3.7/site-packages/sqlalchemy/engine/default.py in do_execute(self, cursor, statement, parameters, context)
    508     def do_execute(self, cursor, statement, parameters, context=None):
--> 509         cursor.execute(statement, parameters)
    510 

OperationalError: (sqlite3.OperationalError) no such table: practice_names [SQL: "update practice_names set Region = 'test' where Region is null;"] (Background on this error at: http://sqlalche.me/e/e3q8)

During handling of the above exception, another exception occurred:

PandaSQLException                         Traceback (most recent call last)
<ipython-input-158-f1734320a61f> in <module>
      6 print(missing_region)
      7 
----> 8 A= pysqldf("update practice_names set Region = 'test' where Region is null;")
      9 
     10 

<ipython-input-158-f1734320a61f> in <lambda>(q)
      1 from pandasql import sqldf
----> 2 pysqldf = lambda q: sqldf(q, globals())
      3 
      4 ##After inspecting the practice names dataset we notice missing values for region
      5 missing_region= pysqldf("SELECT COUNT(DISTINCT Practice_ID) as counter FROM practice_names where Region is null ;")

~/anaconda3/lib/python3.7/site-packages/pandasql/sqldf.py in sqldf(query, env, db_uri)
    154     >>> sqldf("select avg(x) from df;", locals())
    155     """
--> 156     return PandaSQL(db_uri)(query, env)

~/anaconda3/lib/python3.7/site-packages/pandasql/sqldf.py in __call__(self, query, env)
     61                 result = read_sql(query, conn)
     62             except DatabaseError as ex:
---> 63                 raise PandaSQLException(ex)
     64             except ResourceClosedError:
     65                 # query returns nothing

PandaSQLException: (sqlite3.OperationalError) no such table: practice_names [SQL: "update practice_names set Region = 'test' where Region is null;"] (Background on this error at: http://sqlalche.me/e/e3q8)

我期望所有的null值都变为“ missing” 但是代码不会执行

发生的是一条错误消息，指出我要更新的表不存在-尽管该表确实拼写正确。

Answer 1

如果这仍然是一个问题：update 语句不起作用，因为它根本没有实现，请参阅 https://github.com/yhat/pandasql/issues/83 - 有一个 PR 待处理但目前尚未合并；暂时和我自己的目的，我在本地修补了 sqldf.py，没什么大不了的，但是“脏”

更新表语句在PandaSQL中不起作用

1 个答案: