问题
I am trying to run a SQL command using pyodbc in python. in which SQL command contains multiple SELECT commands and IF statements.
but I am getting an error as follows
columns = [col_desc[0] for col_desc in cursor.description]
TypeError: 'NoneType' object is not iterable
import pyodbc
import pandas as pd
conn = pyodbc.connect("DRIVER={SQL Server};"
"SERVER=server_name;"
"DATABASE=master;"
"Trusted_Connection=yes;")
cursor = conn.cursor()
script="""
If object_id ('tempdb..#Temp1')is not null
drop table #Temp1
Select distinct a1.some_ID into #Temp1
from DOC.dbo.Document_tbl (NOLOCK)a1
from #Temp1 a1
If object_id ('tempdb..#Temp2')is not null
Drop table #Temp2
select distinct v2.some_data
into #Temp2 from tbl_name (nolock) v2
If object_id ('tempdb..#Results')is not null
drop table #Results
select distinct a1.*,b1.####
into #Results
from #Temp1 a1
left join #Temp2 b1 on a1.## = b1.##
Select * from #Results
"""
df = pd.read_sql(script, cnxn)
writer = pd.ExcelWriter('result.xlsx')
df.to_excel(writer, sheet_name ='bar')
writer.save()
回答1:
SQL command text that contains multiple SQL statements is called an anonymous code block. An anonymous code block can return multiple results, where each result can be
- a row count,
- a result set containing zero or more rows of data, or
- an error.
The following example fails ...
sql = """\
SELECT 1 AS foo INTO #tmp;
SELECT * FROM #tmp;
"""
df = pd.read_sql_query(sql, cnxn)
# TypeError: 'NoneType' object is not iterable
... because the first SELECT ... INTO returns a row count before the second SELECT returns its result set.
The fix is to start the anonymous code block with SET NOCOUNT ON; which suppresses the row count and only returns the result set:
sql = """\
SET NOCOUNT ON;
SELECT 1 AS foo INTO #tmp;
SELECT * FROM #tmp;
"""
df = pd.read_sql_query(sql, cnxn)
# no error
来源：https://stackoverflow.com/questions/57866905/typeerror-nonetype-object-is-not-iterable-from-pandas-read-sql