Home Database Mysql Tutorial mssql和MySQL数据库不同之处有哪些?

mssql和MySQL数据库不同之处有哪些?

Jun 07, 2016 pm 04:14 PM
mssql mysql different Which database

我最近在做关于mssql转换成MySQL数据库的实际操作中,总结了一点实际经验,于是今天拿出和大家一同分享一下。主要是讲述mssql和MySQL数据库的不同之处,同时这些也会在不断更新。也希望大家补充。 1 MySQL支持enum,和set类型,sql server不支持 2 MySQL不支

我最近在做关于mssql转换成MySQL数据库的实际操作中,总结了一点实际经验,于是今天拿出和大家一同分享一下。主要是讲述mssql和MySQL数据库的不同之处,同时这些也会在不断更新。也希望大家补充。

1 MySQL支持enum,和set类型,sql server不支持

2 MySQL不支持nchar,nvarchar,ntext类型

3 MySQL的递增语句是AUTO_INCREMENT,而mssql是identity(1,1)

4 msms默认到处表创建语句的默认值表示是((0)),而在MySQL里面是不允许带两括号的

5 MySQL需要为表指定存储类型

6 mssql识别符是[],[type]表示他区别于关键字,但是MySQL数据库却是 `,也就是按键1左边的那个符号

7 mssql支持getdate()方法获取当前时间日期,但是MySQL里面可以分日期类型和时间类型,获取当前日期是cur_date(),当前完整时间是 now()函数

8 mssql不支持replace into 语句,但是在最新的sql20008里面,也支持merge语法

9 MySQL支持insert into table1 set t1 = ‘’, t2 = ‘’ ,但是mssql不支持这样写

10 MySQL支持insert into tabl1 values (1,1), (1,1), (1,1), (1,1), (1,1), (1,1), (1,1)

11 mssql不支持limit语句,是非常遗憾的,只能用top 取代limt 0,N,row_number() over()函数取代limit N,M

12 MySQL数据库在创建表时要为每个表指定一个存储引擎类型,而mssql只支持一种存储引擎

13 MySQL不支持默认值为当前时间的datetime类型(mssql很容易做到),在MySQL里面是用timestamp类型

14 mssql里面检查是否有这个表再删除,需要这样:

if exists (select * from dbo.sysobjects where id = object_id(N'uc_newpm') and OBJECTPROPERTY(id, N'IsUserTable') = 1)

但是在MySQL里面只需要 DROP TABLE IF EXISTS cdb_forums;

15 MySQL支持无符号型的整数,那么比不支持无符号型的mssql就能多出一倍的最大数存储

16 MySQL不支持在mssql里面使用非常方便的varchar(max)类型,这个类型在mssql里面既可做一般数据存储,也可以做blob数据存储

17 MySQL数据库创建非聚集索引只需要在创建表的时候指定为key就行,比如:KEY displayorder (fid,displayorder) 在mssql里面必须要:create unique nonclustered index index_uc_protectedmembers_username_appid on dbo.uc_protectedmembers

(username asc,appid asc)

18 MySQL text字段类型不允许有默认值

19MySQL的一个表的总共字段长度不超过65XXX。

20一个很表面的区别就是MySQL的安装特别简单,而且文件大小才110M(非安装版),相比微软这个庞然大物,安装进度来说简直就是.....

21MySQL的管理工具有几个比较好的,MySQL_front,和官方那个套件,不过都没有SSMS的使用方便,这是MySQL很大的一个缺点。

22MySQL的存储过程只是出现在最新的版本中,稳定性和性能可能不如mssql。

23 同样的负载压力,MySQL要消耗更少的CPU和内存,mssql的确是很耗资源。

24php连接MySQL数据库和mssql的方式都差不多,只需要将函数的MySQL替换成mssql即可。

25MySQL支持date,time,year类型,mssql到2008才支持date和time。


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