python 數據庫查詢返回list或tuple實例


MySQLdb默認查詢結果都是返回tuple,輸出時候不是很方便,必須按照0,1這樣讀取,無意中在網上找到簡單的修改方法,就是傳遞一個cursors.DictCursor就行。

默認程序:

import MySQLdb

db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')

cur = db.cursor()

cur.execute('select * from user')

rs = cur.fetchall()

print rs

# 返回類似如下

# ((1000L, 0L), (2000L, 0L), (3000L, 0L))

修改后:

import MySQLdb

import MySQLdb.cursors

db = 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

# 返回類似如下

# ({'age': 0L, 'num': 1000L}, {'age': 0L, 'num': 2000L}, {'age': 0L, 'num': 3000L})

或者也可以用下面替換connect和cursor部分

db = MySQLdb.connect(host='localhost', user='root', passwd='123456', db='test')

cur = db.cursor(cursorclass=MySQLdb.cursors.DictCursor)

我的實踐:

輸出為元組類型:

import pymysql

 

db = pymysql.connect("localhost", "root", "123456", "filestore")

cursor = db.cursor()

sql='select * from tablelist where id>%s' %4

#查詢方法一

cursor.execute(sql)

result=cursor.fetchall()

print('result',result)

 

sql2='select * from tablelist where id>%s'

values=('4') # 此處為元組類型

#查詢方法二

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))

#對((6, 'engineeringdata20180901', '1535731200'),)類型數據的提取

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()

#輸出結果:

result ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))

result2 ((6, 'engineeringdata20180901', '1535731200'), (618, 'engineeringdata20180904', '1535990400'))

type(result3) <class 'tuple'>

[6, 618]

['1535731200', '1535990400']

['engineeringdata20180901', 'engineeringdata20180904']

輸出為list類型:

list_id=[]

list_tablename=[]

list_tabletime=[]

list=get_list('select * from tablelist where id>%s',[4])

print('list:',list)

# 對[{'id': 6, 'tablename': 'engineeringdata20180901', 'tabletime': '1535731200'},]類型數據的提取

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)

# 輸出結果為:

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']

補充知識:python下 將 pymysql 返回的元組數據轉換為列表

我就廢話不多說了,大家還是直接看代碼吧!

from itertools import chain

...

sql="select elems from table"

cursor.execute(sql)

elems = cursor.fetchall()

resultlist = list(chain.from_iterable(elems))

...

以上這篇python 數據庫查詢返回list或tuple實例就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支持。


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