sql

Posted 2020-11-24 real-admin

import pymysql

con = pymysql.connect(host="127.0.0.1",user="root",passwd="root",db="test")
cursor = con.cursor()

sql = "insert into test2(name,gender) select distinct name,gender from test1;"
cursor.execute(sql)


con.commit()

cursor.close()
con.close()

　　name和gender同时不同才会取出。字段名称可以不一致，但是顺序绝对不能错。

 

sql = "alter table test1 alter moren set default 0;" # 设置默认值，但是之前的数据不会发生变更

　　

sql = "update test1 set moren=0;"  # 原有数据全部设置为0

　　

sql = "update test1 set moren=1,gender2=‘女‘;" # 设置多列

　　

 

sql = "update test1 set moren=6 where name=‘张三‘;" # 条件更新

　　

 

 

 

a = {"a":"a","b":"b","c":"c"}

a = json.dumps(a)
print(a)

a = json.loads(a)
print(a)


{"a": "a", "b": "b", "c": "c"}
{‘a‘: ‘a‘, ‘b‘: ‘b‘, ‘c‘: ‘c‘}