如何日期变量传递给一个SQL查询在Python

Question

Python3.5 SQL服务器2012标准

包pypyodbc

此代码的工作

myConnection = pypyodbc.connect('Driver={SQL Server};' 
           'Server=myserver;' 
           'Database=mydatabase;' 
           'TrustedConnection=yes') 
myCursor = myConnection.cursor() 
sqlstr = ("Select * From DB.Table1 Where DB.Table1.Date <= '7/21/2016'") 
myCursor.execute(sqlstr) 
results = myCursor.fetchall() 

但是，日期必须是变量由用户传入。我做了几个MODS的sqlstr但继续在myCursor.execute错误： “类型错误：字节或整数地址预期，而不是元组实例”

sqlstr = ("Select * From DB.Table1 Where DB.Table1.Date <= %s", '7/21/2016') 

错误

sqlstr = ("Select * From DB.Table1 Where DB.Table1.Date <= '%s'", '7/21/2016') 

错误

sqlstr = ("Select * From DB.Table1 Where DB.Table1.Date <= ?", "'7/21/2016'") 

错误

var1 = "'7/21/2016'" 
sqlstr = ("Select * From DB.Table1 Where DB.Table1.Date <= %s", var1) 

等等。不过，我确信有一个正确的方法...

感谢您的任何帮助！

Answer 1

I am sure there is one correct way

是的，这是一个参数化查询：

date_var = datetime(2016, 7, 21) 
sql = """\ 
SELECT [ID], [LastName], [DOB] FROM [Clients] WHERE [DOB]<? 
""" 
params = [date_var] # list of parameter values 
crsr.execute(sql, params) 
for row in crsr.fetchall(): 
    print(row)