mysql Q查询和F查询

Q查询

查看底层SQL

def showsql():
    from django.db import connection
    print connection.queries[-1]['sql']

条件与操作

from student.models import *
from django.db.models import Q,F
Stu.objects.filter(Q(sno=1)&Q(sname='zhangsan'))
<QuerySet [<Stu: Stu:zhangsan,88>]>

    
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE (`t_stu`.`sno` = 1 AND `t_stu`.`sname` = 'zhangsan') LIMIT 21


Stu.objects.get(Q(sno=1)&Q(sname='zhangsan'))
<Stu: Stu:zhangsan,88>
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE (`t_stu`.`sno` = 1 AND `t_stu`.`sname` = 'zhangsan')

条件或操作

from student.models import *
from django.db.models import Q,F
Stu.objects.filter(Q(sno=1)&Q(sname='zhangsan'))
<QuerySet [<Stu: Stu:zhangsan,88>]>

    
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE (`t_stu`.`sno` = 1 AND `t_stu`.`sname` = 'zhangsan') LIMIT 21


Stu.objects.get(Q(sno=1)&Q(sname='zhangsan'))
<Stu: Stu:zhangsan,88>
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE (`t_stu`.`sno` = 1 AND `t_stu`.`sname` = 'zhangsan')

条件非操作

Stu.objects.filter(~Q(sname='zhangsan'))
<QuerySet [<Stu: Stu:lisi,90>, <Stu: Stu:wangwu,99>, <Stu: Stu:zhangjie,66>, <Stu: Stu:xiena,89>]>
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE NOT (`t_stu`.`sname` = 'zhangsan') LIMIT 21


Stu.objects.filter(~Q(sname='zhangsan',sno=1))
<QuerySet [<Stu: Stu:lisi,90>, <Stu: Stu:wangwu,99>, <Stu: Stu:zhangjie,66>, <Stu: Stu:xiena,89>]>
showsql()
SELECT `t_stu`.`sno`, `t_stu`.`sname`, `t_stu`.`score`, `t_stu`.`created`, `t_stu`.`clazz_id` FROM `t_stu` WHERE NOT (`t_stu`.`sno` = 1 AND `t_stu`.`sname` = 'zhangsan') LIMIT 21

F查询

学号大于3的学生成绩加10分

Stu.objects.filter(Q(sno__gt=3)).update(score=F('score')+10)
2L
showsql()
UPDATE `t_stu` SET `score` = (`t_stu`.`score` + 10) WHERE `t_stu`.`sno` > 3

学号大于3的学生入学日期提前2天

import datetime
Stu.objects.filter(Q(sno__gt=3)).update(created=F('created')+datetime.timedelta(days=-2))
2L
showsql()
UPDATE `t_stu` SET `created` = (`t_stu`.`created` + INTERVAL '172800.000000' SECOND_MICROSECOND) WHERE `t_stu`.`sno` > 3