5、删除新表：drop table tabname

6、添加主键sql语句：Alter table tabname add primary key(col)

7、删除主键sql语句：Alter table tabname drop primary key(col)

8.如何修改数据库的名称:sp_renamedb 'old_name', 'new_name'
9：获取当前数据库中的所有用户表select Name from sysobjects where xtype='u' and status>=0
10：获取某一个表的所有字段select name from syscolumns where id=object_id('表名')
11：查看与某一个表相关的视图、存储过程、函数select a.* from sysobjects a, syscomments b where a.id = b.id and b.text like '%表名%'
12：查看当前数据库中所有存储过程select name as 存储过程名称 from sysobjects where xtype='P'
13：查询用户创建的所有数据库select * from master..sysdatabases D where sid not in(select sid from master..syslogins where name='sa')
或者
select dbid, name AS DB_NAME from master..sysdatabases where sid <> 0x01

14.数据库加密:select encrypt('原始密码')
select pwdencrypt('原始密码')
select pwdcompare('原始密码','加密后密码') = 1--相同；否则不相同 encrypt('原始密码')
select pwdencrypt('原始密码')
select pwdcompare('原始密码','加密后密码') = 1--相同；否则不相同
15.取回表中字段:declare @list varchar(1000),@sql nvarchar(1000)
select @list=@list+','+b.name from sysobjects a,syscolumns b where a.id=b.id and a.name='表A'
set @sql='select '+right(@list,len(@list)-1)+' from 表A'
exec (@sql)
16.查看硬盘分区:EXEC master..xp_fixeddrives
17.比较A,B表是否相等sql语句:if (select checksum_agg(binary_checksum(*)) from A)
=
(select checksum_agg(binary_checksum(*)) from B)
print '相等'
else
print '不相等'

18、其他几个常用的sql语句说明：几个简单的基本的sql语句
　　选择：select * from table1 where 范围
　　插入：insert into table1(field1,field2) values(value1,value2)
　　删除：delete from table1 where 范围
　　更新：update table1 set field1=value1 where 范围
　　查找：select * from table1 where field1 like ’%value1%’ ---like的语法非常精妙，查资料!
　　排序：select * from table1 order by field1,field2 [desc]
　　总数：select count * as totalcount from table1
　　求和：select sum(field1) as sumvalue from table1
　　平均：select avg(field1) as avgvalue from table1
　　最大：select max(field1) as maxvalue from table1
　　最小：select min(field1) as minvalue from table1

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