我正在尝试在 python 中使用 pyodbc 运行 SQL 命令。
其中SQL命令包含多个SELECT命令和IF语句。
但我收到如下错误
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()
包含多个 SQL 语句的 SQL 命令文本称为匿名代码块。匿名代码块可以返回多个结果,其中每个结果可以是
- 行数,
- 包含零行或多行数据的结果集,或者
- 一个错误。
下面的例子失败了...
sql = """\
SELECT 1 AS foo INTO #tmp;
SELECT * FROM #tmp;
"""
df = pd.read_sql_query(sql, cnxn)
# TypeError: 'NoneType' object is not iterable
...因为第一个SELECT ... INTO
返回第二个之前的行数SELECT
返回其结果集。
修复方法是使用以下命令启动匿名代码块SET NOCOUNT ON;
它会抑制行计数并仅返回结果集:
sql = """\
SET NOCOUNT ON;
SELECT 1 AS foo INTO #tmp;
SELECT * FROM #tmp;
"""
df = pd.read_sql_query(sql, cnxn)
# no error
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