Python连接SQL server数据库并进行简单查询的操作详解

#pip install pymssql 先安装

import pymssql #导入模块

connect = pymssql.connect('(local)','sa','123456','School')  
#connect = pymssql.connect('服务器名称', '用户名', '密码', '库名')  # 建立连接
if connect:
    print("连接成功")
#输出
连接成功

cursor = connect.cursor()#创建一个游标对象python里的sql语句都要通过cursor来执行
sql="select * from Student" #一个简单的sql查询语句
cursor.execute(sql)#执行sql语句
row = cursor.fetchone() #用fetchone 获取游标的数据,如果是首次就定位首行
while row:  # 循环读取所有结果
 	print(row)
    row = cursor.fetchone()#取下一个内容
cursor.close()
connect.close()
#结果出现乱码,下面我们解决
<pymssql._pymssql.Connection object at 0x0000025DBDEE9F00>
连接成功
(2021402075, 'ÏôÑ×', 'ÄÐ', datetime.datetime(1900, 2, 7, 0, 0), 'MA')
(2021402076, 'ÏôÑ×', 'ÄÐ', datetime.datetime(2003, 3, 18, 0, 0), 'CS')
(2021402077, '´ºÒ°Ó£', 'Å®', datetime.datetime(2009, 4, 20, 0, 0), 'MA')
(2021402078, '´ºÈÕÒ°ñ·', 'Å®', datetime.datetime(2003, 6, 20, 0, 0), 'CS')
(2021402079, 'ÈÕÏò³ûÌï', 'Å®', datetime.datetime(2006, 7, 7, 0, 0), 'MA')
(2021402080, 'ÄÈÃÀ', 'Å®', datetime.datetime(2003, 6, 6, 0, 0), 'CS')

import pymssql #导入模块
connect = pymssql.connect('(local)','sa','123456','School',charset='cp936')  #connect = pymssql.connect('服务器名称', '用户名', '密码', '库名')  # 建立连接
if connect:
    print(connect)
    print("连接成功")
cursor = connect.cursor()
sql = "select * from Student"
cursor.execute(sql)
row = cursor.fetchone()
while row:
    print(row)
    row = cursor.fetchone()
cursor.close()
connect.close()
#结果
<pymssql._pymssql.Connection object at 0x00000115E49A9FC0>
连接成功
(2021402075, '萧炎', '男', datetime.datetime(1900, 2, 7, 0, 0), 'MA')
(2021402076, '萧炎', '男', datetime.datetime(2003, 3, 18, 0, 0), 'CS')
(2021402077, '春野樱', '女', datetime.datetime(2009, 4, 20, 0, 0), 'MA')
(2021402078, '春日野穹', '女', datetime.datetime(2003, 6, 20, 0, 0), 'CS')
(2021402079, '日向雏田', '女', datetime.datetime(2006, 7, 7, 0, 0), 'MA')
(2021402080, '娜美', '女', datetime.datetime(2003, 6, 6, 0, 0), 'CS')
#成功完美的查询

select convert(nvarchar(50),table_colum) 
as 'nvarchar_colum' from mytable where convert(nvarchar(50),table_colum) = '魏本明'
就是将需要转换的列(如,varchar),转换为nvarchar,也可以完成

import pymssql #导入模块
connect = pymssql.connect('(local)','sa','123456','School')  #connect = pymssql.connect('服务器名称', '用户名', '密码', '库名')  # 建立连接
if connect:
    print(connect)
    print("连接成功")

cursor = connect.cursor()#创建一个游标对象python里的sql语句都要通过cursor来执行
sql="select Ssno,convert(nvarchar(50),Snam) as 'a',convert(nvarchar(50),Ssex) as 'b' from Student"
cursor.execute(sql)#执行语句
row = cursor.fetchone()#用fetchone 获取游标的数据,如果是首次就定位首行
print(row)
while row:  # 循环读取所有结果
    print("id=%s,Name=%s，Sex=%s" % (row[0], row[1], row[2]))  # 输出结果
    row = cursor.fetchone()#取下一个内容
cursor.close()
connect.close()
结果:
<pymssql._pymssql.Connection object at 0x0000019C35BBC0C0>
连接成功
(2021402075, '萧炎', '男', datetime.datetime(1900, 2, 7, 0, 0), 'MA')
(2021402076, '萧炎', '男', datetime.datetime(2003, 3, 18, 0, 0), 'CS')
(2021402077, '春野樱', '女', datetime.datetime(2009, 4, 20, 0, 0), 'MA')
(2021402078, '春日野穹', '女', datetime.datetime(2003, 6, 20, 0, 0), 'CS')
(2021402079, '日向雏田', '女', datetime.datetime(2006, 7, 7, 0, 0), 'MA')
(2021402080, '娜美', '女', datetime.datetime(2003, 6, 6, 0, 0), 'CS')

import  pymssql
# 1:创建一个数据库
conn = pymssql.connect('.','sa','123456')#单纯连接数据库
if conn:
    print("连接成功")
cursor = conn.cursor() #创建执行语句
conn.autocommit(True) #创建库的核心!!!
sql_DATA ="""
CREATE DATABASE PY_DATA
ON   PRIMARY
 (NAME = 'PY_DATA',
FILENAME = 'D:\DATA\PY_DATA.MDF' ,
SIZE = 5MB,
MAXSIZE = 20MB,
FILEGROWTH = 20%)
LOG ON
(NAME ='PY_DATA_LOG',
FILENAME = 'D:\DATA\PY_DATA_LOG. LDF',
SIZE = 5MB,
MAXSIZE = 10MB,
FILEGROWTH = 2MB)
"""
cursor.execute(sql_DATA)
cursor.close()
conn.autocommit(False)
conn.close()
----------------------------------------------------------------------------
#2:创建一个表
import pymssql
##连接
conn = pymssql.connect('.','sa','123456','School')
if conn:
    print("连接成功")

##操作
cursor = conn.cursor()
conn.autocommit(True)#是修改表的结构都要有吗?
sql_TABLE = """
Create Table Student_3(
ID int primary key,
Name varchar(50),
Age int)
"""
cursor.execute(sql_TABLE)
conn.autocommit(False)
conn.close()
----------------------------------------------------------------------------

3:为这个表插入数据
import  pymssql
conn = pymssql.connect('.','sa','123456','PY_DATA')
if conn:
    print("True")

cursor = conn.cursor()
a = "松仁、秉峰、泳纪海奉、威剑、颂和、祥益、腾恩、柏铄、孟深、忠庄、轩哲、铠鑫、仕伦、儒亿、积进信钦、贤元、程基、安泉、树昌、祝斌、一科、游湖、普济、中坚"
a = a.split("、")
for i in range(len(a)):
    sql_insert = f"insert into Student Values({i},'{a[i]}',18)"
    print(sql_insert)
    cursor.execute(sql_insert)
    conn.commit()
cursor.close()
conn.close()
----------------------------------------------------------------------------

4:更新插入的数据
import pymssql
conn = pymssql.connect('.','sa','123456','PY_DATA')
if conn:
    print("True")

cursor = conn.cursor()
sql_updata = "update student set Name='消息' where ID = 12"
cursor.execute(sql_updata)
conn.commit()
cursor.close()
conn.close()


----------------------------------------------------------------------------
5:查询前三行数据
import pymssql
conn = pymssql.connect('.','sa','123456','PY_DATA',charset='cp936')
if conn:
    print("True")
cursor = conn.cursor()
sql_select = "Select Top 3 * From Student"
cursor.execute(sql_select)
row =1
while row:
    row = cursor.fetchone()
    print(row)
cursor.close()
conn.close()
----------------------------------------------------------------------------
6:插入一列属性
import pymssql
conn = pymssql.connect('.','sa','123456','School')
cursor = conn.cursor()
conn.autocommit(True)
sql_insertbase = "Alter table Student_3 add idname int Null"
cursor.execute(sql_insertbase)
cursor.close()
conn.close()