1 #! /usr/bin/env python
2 # -*- coding:utf-8 -*-
3 import pymysql
4 conn = pymysql.connect(host=
'127.0.0.1', port=3306, user=
'root', passwd=
'123', db=
't1')
5 cursor=
conn.cursor()
6 # exc=cursor.execute("update tb1 set user='88' ")
7 # exc=cursor.execute("insert into tb1(user,date) VALUES ('89','2017-07-20')")
8 # exc=cursor.execute("insert into tb1(user,date) VALUES (%s,%s)",('zj','2017-07-20'))
9 # exc=cursor.executemany("insert into tb1(user,date) VALUES (%s,%s)",
10 # [('zj','2017-07-20'),('nn','2017-07-20')])
11
12 # cursor=conn.cursor(cursor=pymysql.cursors.DictCursor)
13 # 把拿到的数据便成字典
14 # effect_row = cursor.execute("select * from tb1")
15 # conn.commit()
16 # ret=cursor.fetchall()
17 # print(ret)
18 # r=cursor.fetchone()
19 # print(r)
20 # cursor.fetchmany(2)
21 # 关闭游标
22 cursor.close()
23 # 关闭连接
24 conn.close()
View Code
连表
-- CREATE table person(
-- nid int not NULL auto_increment,
-- name VARCHAR(32) not NULL,
-- email VARCHAR(32) not NULL,
-- part1_nid int not NULL ,
-- PRIMARY KEY (nid),
-- CONSTRAINT fk_person_part1 FOREIGN KEY (part1_nid) REFERENCES part1(nid)
-- )
-- alter table person drop foreign key fk_person_part1 ;
-- 连表
SELECT
person.name,
part.part
FROM
person
LEFT JOIN part
on person.part1_nid
=part.nid
WHERE
part.part='jj'
View Code
A left join B on a.xx=b.xx
A表中所有数据罗列
B中只列A想对应的数据
A inner join B
自动忽略未建立关系的数据
转载于:https://www.cnblogs.com/ezway/p/7207587.html
