Python 执行sqlcontext.sql查询时强制转换为字符串

当我运行这个脚本时

dayfilename = (datetime.strptime(day, '%d-%m-%Y') + timedelta(days=-1)).strftime(format='%d%m%Y')
dayfilename = str(dayfilename)
query = "select t1.a as val1, {} as val2 from table1 t1".format(dayfilename)
df = sqlContext.sql(query)

我正在得到输出

+------------+-------+
|        val1|   val2|
+------------+-------+
|919955123456|7102020|
|919955123456|7102020|
+------------+-------+

---

虽然我希望值为07102020，但找到了修复程序。在单引号内给出了字段

query=“从表1 t1中选择t1.a作为val1，{}作为val2”。格式化（dayfilename）