django获取指定列的数据

model一般都是有多个属性的，但是很多时候我们又只需要查询特定的某一个，这个时候可以用到values和values_list

[values()](https://docs.djangoproject.com/en/1.9/ref/models/querysets/#values)values()¶values(*fields)¶Returns a QuerySet that returns dictionaries, rather than model instances, when used as an iterable.Each of those dictionaries represents an object, with the keys corresponding to the attribute names of model objects.

[values_list()](https://docs.djangoproject.com/en/1.9/ref/models/querysets/#values-list)values_list()¶values_list(*fields, flat=False)¶This is similar to values() except that instead of returning dictionaries, it returns tuples when iterated over. Each tuple contains the value from the respective field passed into the values_list() call — so the first item is the first field, etc.

看下面的代码：

利用values查询

from attendence.models import Employeefrom attendence.models import EmployeeIP#获取一个字段ipList = EmployeeIP.objects.values("IP").first()print(type(ipList))# 
    
     print(ipList)# {'IP': '192.168.1.41'}#获取多个字段empList = Employee.objects.values("first_name", "last_name", "email")[0:2]print(type(empList))# 
     
      print(empList)# [#   {'last_name': 'Wei', 'first_name': 'Vena', 'email': 'Vena@test.com'},#   {'last_name': 'Wan', 'first_name': 'Mark', 'email': 'mwan@test.com'}# ]

利用values_list查询

ipList = EmployeeIP.objects.values_list("IP").first()print(type(ipList))# 
    
     print(ipList)# ('192.168.1.111',)ipList = EmployeeIP.objects.values_list("IP")[0:2]print(type(ipList))# 
     
      print(ipList)# [('192.168.1.41',), ('192.168.1.44',)]print(type(ipList[0]))# 
      
       print(ipList[0])# 192.168.1.111