Passing query parameters in Pandas - sql-server-2005

Question

Trying to write a simple pandas script which executes a query from SQL Server with WHERE clause. However, the query doesnt return any values. Possibly because the parameter is not passed? I thought we could pass the key-value pairs as below. Can you please point out what i am doing wrong here?
Posting just the query and relevant pieces. All the libraries have been imported as needed.
curr_sales_month = '2015-08-01'
sql_query = """SELECT sale_month,region,oem,nameplate,Model,Segment,Sales FROM [MONTHLY_SALES] WHERE Sale_Month = %(salesmonth)s"""
print ("Executed SQL Extract", sql_query)
df = pd.read_sql_query(sql_query,conn,params={"salesmonth":curr_sales_month})
The program returned with:
Closed Connection - Fetched 0 rows for Report
Process finished with exit code 0

Answer 1

Further to my comment. Here is an example that uses pyodbc to communicate to sql server and demonstrates passing a variable.
import pandas as pd
import pyodbc
pd.set_option('display.max_columns',50)
pd.set_option('display.width',5000)
conn_str = r"DRIVER={0};SERVER={1};DATABASE={2};UID={3};PWD={4}".format("SQL Server",'.','master','user','pwd')
cnxn = pyodbc.connect(conn_str)
sql_statement = "SELECT * FROM sys.databases WHERE database_id = ?"
df = pd.read_sql_query(sql = sql_statement, con = cnxn, params = [2])
cnxn.close()
print df.iloc[:,0:2].head()
which produces:
name database_id
0 tempdb 2
And if you wish to pass multiple parameters:
sql_statement = "SELECT * FROM sys.databases WHERE database_id > ? and database_id < ?"
df = pd.read_sql_query(sql = sql_statement, con = cnxn, params = [2,5])
cnxn.close()
print df.iloc[:,0:2].head()
which produces:
name database_id
0 model 3
1 msdb 4
my preferred way with dynamic inline sql statements
create_date = '2015-01-01'
name = 'mod'
sql_statement_template = r"""SELECT * FROM sys.databases WHERE database_id > {0} AND database_id < {1} AND create_date > '{2}' AND name LIKE '{3}%'"""
sql_statement = sql_statement_template.format('2','5',create_date,name)
print sql_statement
yields
SELECT * FROM sys.databases WHERE database_id > 2 AND database_id < 5 AND create_date > '2015-01-01' AND name LIKE 'mod%'
A further benefit if you do print this out, is you can copy and paste the sql commnand to management studio (or equivalent) and test your sql syntax easily.
and result should be:
name database_id
0 model 3
So this example demonstrates handling: date,string and int datatypes.
Including a LIKE with wildcard %