python - 无法创建第二个数据框 python pandas

Question

我的第二个数据框在创建它时没有加载值。有什么帮助可以解释为什么它不起作用吗？当我将光标设置为列表时，它里面有一堆值，但是无论出于何种原因，当我尝试第二次使用 pandas 进行正常的数据帧加载时，它都不起作用。

我的代码:

    conn = pyodbc.connect(constr, autocommit=True)
    cursor = conn.cursor()
    secondCheckList = []
    checkCount = 0
    maxValue = 0
    strsql = "SELECT * FROM CRMCSVFILE"
    cursor = cursor.execute(strsql)
    cols = []
    SQLupdateNewIdField = "UPDATE CRMCSVFILE SET NEW_ID = ? WHERE Email_Address_Txt = ? OR TELEPHONE_NUM = ? OR DRIVER_LICENSE_NUM = ?"
    for row in cursor.description:
        cols.append(row[0])
    df = pd.DataFrame.from_records(cursor)
    df.columns = cols
    newIdInt = 1
    for row in range(len(df['Email_Address_Txt'])):
        #run initial search to figure out the max number of records. Look for email, phone, and drivers license, names have a chance not to be unique
        SQLrecordCheck = "SELECT * FROM CRMCSVFILE WHERE Email_Address_Txt = '" + str(df['Email_Address_Txt'][row]) + "' OR TELEPHONE_NUM = '" + str(df['Telephone_Num'][row]) + "' OR DRIVER_LICENSE_NUM = '" + str(df['Driver_License_Num'][row]) + "'"
##        print(SQLrecordCheck)
        cursor = cursor.execute(SQLrecordCheck)
## maxValue is indeed a list filled with records
            maxValue =(list(cursor))
## THIS IS WHERE PROBLEM OCCURS
        tempdf = pd.DataFrame.from_records(cursor)

Answer 1

为什么不直接使用 pd.read_sql_query("your_query", conn) 这会将查询结果作为数据帧返回，并且需要更少的代码。另外，您将光标设置为顶部的cursor.execute(strsql)，然后尝试在for循环中再次调用光标上的执行，但您不能再在光标上调用执行，您必须设置光标= conn.cursor()再次。