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Python 查询SQL Server数据库时,结果对象不返回行_Python_Sql_Sql Server_Pandas_Sqlalchemy - Fatal编程技术网

Python 查询SQL Server数据库时,结果对象不返回行

Python 查询SQL Server数据库时,结果对象不返回行,python,sql,sql-server,pandas,sqlalchemy,Python,Sql,Sql Server,Pandas,Sqlalchemy,守则: engine = db.engine conn = engine.connect() query = open('sql_file.sql', 'r') df = pd.read_sql_query(query.read(), conn) 返回以下错误: sqlalchemy.exc.ResourceClosedError: This result object does not return rows. It has been closed automatically. 我在sql

守则:

engine = db.engine
conn = engine.connect()
query = open('sql_file.sql', 'r')
df = pd.read_sql_query(query.read(), conn)
返回以下错误:

sqlalchemy.exc.ResourceClosedError: This result object does not return rows. It has been closed automatically.

我在sql文件中的查询在SSMS中运行得非常好,并返回一个我想用Pandas读取的大表。为什么它不返回任何行,以及如何以某种方式执行sql文件,使数据进入数据帧?

也有类似的问题。据我所见,它源于SQL Server将临时表创建的结果反馈为结果集。根据您的查询所执行的操作,它可能会返回许多结果集以及所需的结果集。它可能来自熊猫在引擎盖下使用的炼金术行为

一些解决方案是在查询顶部添加
SET NOCOUNT ON
SET ANSI_WARNINGS OFF
。我试过了,但还是不行

最后的工作是从sqlalchemy获取光标并将光标移动到所需的结果集。返回的结果是一个元组列表,然后可以使用
DataFrame.from_records()
来构建数据框架

raw_connection = db_engine.raw_connection()
try:
    cursor = raw_connection.cursor()
    cursor.execute(sql)
    cursor.nextset()

    column_names = [column[0] for column in cursor.description]
    rows = cursor.fetchall() # List of tuples

    cursor.close()
finally:
    raw_connection.close()

# Use from_records for a list of tuples
df = pandas.DataFrame.from_records(data=rows, columns=column_names, index=None)
见: 以及:

请出示一份表格(将查询包含在问题中)。