python中查询语句怎么写

import sys
import cx_Oracle
import os
class handleDataBase:

def __init__(self,user,passwd,server,sql):
    self.user=user
    self.passwd=passwd
    self.server=server
    self.sql=sql
    self.conn = cx_Oracle.connect("%s/%s@%s"%(self.user,self.passwd,self.server))

def selectDB(self):
    cursor = self.conn.cursor()
    cursor.execute("select count(1) from search_item_08")
    ret = cursor.fetchall()
    cursor.close()
    print ret
    return ret

def closeDB(self):

      self.conn.close()
   

if name == "__main__":

if len(sys.argv) < 4:
      print "Need Arguments: user passwd server"
      sys.exit(1)
     
user=sys.argv[1]
passwd=sys.argv[2]
server=sys.argv[3]
#sql='select count(1) from search_item_08;' #注意这里要改
sql = open('a.sql','r').read() #改成从文件读取

#接下来就访问数据库了
handleDB = handleDataBase(user,passwd,server,sql)
handleDB.selectDB()
handleDB.closeDB()