Working with dates in Access using pyodbc giving “Too few parameters” error

Question

I am using Python with a pyodbc import.

I am using Microsoft Office 2013 64bit.

I am attempting to query an accdb database to select distinct dates within a range and assign them to a cursor so I can then append them to a list.

My Access database has a table named Closing_prices, and a column named Date_, which has the data type "Date/Time".

My code is as follows:

cursor=conx.cursor()
query="select distinct Date_ FROM Closing_prices where Date_ >= '10/8/2011' and Date_ < '30/04/2014'"
cursor.execute(query)
dates=list()
for date in cursor:
   dates.append(date[0])

However I am receiving the error message:

Traceback (most recent call last):
  File "C:/Users/Stuart/PycharmProjects/untitled/Apache - Copy.py", line 20, in <module>
cursor.execute(query)
pyodbc.Error: ('07002', '[07002] [Microsoft][ODBC Microsoft Access Driver] Too few parameters. Expected 1. (-3010) (SQLExecDirectW)')

As Date_ is a datetime, I have also tried:

query="select distinct Date_ FROM Closing_prices where Date_ >= '10/8/2011 00:00:00' and Date_ < '30/04/2014 00:00:00'"

When I run:

cursor = conx.cursor()
query="select Date_ FROM Closing_prices"
cursor.execute(query)

for row in cursor:
    print row

print type(row[0])

I get the following output as an example:

(datetime.datetime(2014, 3, 24, 0, 0), )
(datetime.datetime(2014, 3, 25, 0, 0), )
(datetime.datetime(2014, 3, 26, 0, 0), )
(datetime.datetime(2014, 3, 27, 0, 0), )

I am relatively new to Python and even newer to SQL queries, so could someone please point out where I am going wrong, and perhaps how I can change my code to help me append the distinct dates into a list as desired.

Many thanks.

Answer 1

To

1. save yourself the hassle of finding the applicable date delimiter, and
2. promote good coding practice

you should simply use a parameterized query like this:

db = pyodbc.connect(connStr)
crsr = db.cursor()
sql = """
SELECT DISTINCT Date_ FROM Closing_prices WHERE Date_ >= ? AND Date_ < ?
"""
params = (datetime.date(2011, 8, 10), datetime.date(2014, 4, 30))
crsr.execute(sql, params)