python如何实现数据库查询返回list或tuple
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MySQLdb默认查询结果都是返回tuple,输出时候不是很方便,必须按照0,1这样读取,无意中在网上找到简单的修改方法,就是传递一个cursors.DictCursor就行。
默认程序:
import MySQLdbdb = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')cur = db.cursor()cur.execute('select * from user')rs = cur.fetchall()print rs# 返回类似如下# ((1000L, 0L), (2000L, 0L), (3000L, 0L))
修改后:
import MySQLdbimport MySQLdb.cursorsdb = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test', cursorclass=MySQLdb.cursors.DictCursor)cur = db.cursor()cur.execute('select * from user')rs = cur.fetchall()print rs# 返回类似如下# ({'age': 0L, 'num': 1000L}, {'age': 0L, 'num': 2000L}, {'age': 0L, 'num': 3000L})
或者也可以用下面替换connect和cursor部分
db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')
cur = db.cursor(cursorclass=MySQLdb.cursors.DictCursor)
我的实践:
输出为元组类型:
import pymysql db = pymysql.connect("localhost", "root", "123456", "filestore")cursor = db.cursor()sql='select * from tablelist where id>%s' %4#查询方法一cursor.execute(sql)result=cursor.fetchall()print('result',result) sql2='select * from tablelist where id>%s'values=('4') # 此处为元组类型#查询方法二cursor.execute(sql2,values)result2=cursor.fetchall()print('result2',result2)id_list=[]tablename_list=[]tabletime_lsit=[]cursor.execute('select * from tablelist where id>%s',[4,])result3=cursor.fetchall()print('type(result3)',type(result3))#对((6, 'engineeringdata20180901', '1535731200'),)类型数据的提取for i in range(len(result3)): id_list.append(result3[i][0]) tablename_list.append(result3[i][1]) tabletime_lsit.append(result3[i][2])print(id_list)print(tabletime_lsit)print(tablename_list)cursor.close()db.close()#输出结果:result ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))result2 ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))type(result3) <class 'tuple'>[6, 618]['1535731200', '1535990400']['engineeringdata20180901', 'engineeringdata20180904']
输出为list类型:
list_id=[]list_tablename=[]list_tabletime=[]list=get_list('select * from tablelist where id>%s',[4])print('list:',list)# 对[{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'},]类型数据的提取for i in range(len(list)): print(list[i]) list_id.append(list[i]['id']) list_tablename.append(list[i]['tablename']) list_tabletime.append(list[i]['tabletime'])print('list_id:',list_id)print('list_tabletime:',list_tabletime)print('list_tablename:',list_tablename)# 输出结果为:list: [{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'}, {'id': 618, 'tablename': 'engineeringdata20180904', 'tabletime': '1535990400'}]{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'}{'id': 618, 'tablename': 'engineeringdata20180904', 'tabletime': '1535990400'}list_id: [6, 618]list_tabletime: ['1535731200', '1535990400']list_tablename: ['engineeringdata20180901', 'engineeringdata20180904']
补充知识:python下 将 pymysql 返回的元组数据转换为列表
我就废话不多说了,大家还是直接看代码吧!
from itertools import chain...sql="select elems from table"cursor.execute(sql)elems = cursor.fetchall()resultlist = list(chain.from_iterable(elems))...
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