2023年4月17日发(作者:韩文名字)数据库基本_SQL语句大全
学会数据库是很实用D~~记录一些常用的sql语句...有入门有提高
有见都没见过的...好全...收藏下...
其实一般用的就是查询,插入,删除等语句而已....但学学存储过程是好
事...以后数据方面的东西就不用在程序里搞喽..而且程序与数据库只要
一个来回通讯就可以搞定所有数据的操作....
一、基础
1、说明:创建数据库
Create DATABASE databa-name
2、说明:删除数据库
drop databa dbname
3、说明:备份sql rver
--- 创建 备份数据的 device
USE master
EXEC sp_addumpdevice ‘disk‘, ‘testBack‘, ‘c:mssql7backup‘
--- 开始 备份
BACKUP DATABASE pubs TO testBack
4、说明:创建新表
create table tabnamecol1 type1 not null primary key,col2 type2 not null,..
根据已有的表创建新表:
A:create table tab_new like tab_old 使用旧表创建新表
B:create table tab_new as lect col1,col2… from tab_old definition only
5、说明:删除新表
drop table tabname
6、说明:增加一个列
Alter table tabname add column col type
注:列增加后将不能删除;DB2中列加上后数据类型也不能改变,唯一能
改变的是增加varchar类型的长度;
7、说明:添加主键: Alter table tabname add primary keycol
说明:删除主键: Alter table tabname drop primary keycol
8、说明:创建索引:create unique index idxname on tabnamecol….
删除索引:drop index idxname
注:索引是不可更改的,想更改必须删除重新建;
9、说明:创建视图:create view viewname as lect statement
删除视图:drop view viewname
10、说明:几个简单的基本的sql语句
选择:lect from table1 where 范围
插入:inrt into table1field1,field2 valuesvalue1,value2
删除:delete from table1 where 范围
更新:update table1 t field1=value1 where 范围
查找:lect from table1 where field1 like ’%value1%’ ---like的语法很精
妙,查资料
排序:lect from table1 order by field1,field2 desc
总数:lect count as totalcount from table1
求和:lect sumfield1 as sumvalue from table1
平均:lect avgfield1 as avgvalue from table1
最大:lect maxfield1 as maxvalue from table1
最小:lect minfield1 as minvalue from table1
11、说明:几个高级查询运算词
A: UNION 运算符
UNION 运算符通过组合其他两个结果表例如 TABLE1 和 TABLE2
并消去表中任何重复行而派生出一个结果表;当 ALL 随 UNION 一起
使用时即 UNION ALL,不消除重复行;两种情况下,派生表的每一行不是
来自 TABLE1 就是来自 TABLE2;
B: EXCEPT 运算符
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行
并消除所有重复行而派生出一个结果表;当 ALL 随 EXCEPT 一起使
用时 EXCEPT ALL,不消除重复行;
C: INTERSECT 运算符
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并
消除所有重复行而派生出一个结果表;当 ALL 随 INTERSECT 一起使
用时 INTERSECT ALL,不消除重复行;
注:使用运算词的几个查询结果行必须是一致的;
12、说明:使用外连接
A、left outer join:
左外连接左连接:结果集几包括连接表的匹配行,也包括左连接表的所有
行;
SQL: lect , , , , , from a LEFT OUT JOIN b ON =
B:right outer join:
右外连接右连接:结果集既包括连接表的匹配连接行,也包括右连接表的
所有行;
C:full outer join:
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记
录;
二、提升
1、说明:复制表只复制结构,源表名:a 新表名:b Access可用
法一:lect into b from a where 1<>1
法二:lec路由器登陆网址
t top 0 into b from a
2、说明:拷贝表拷贝数据,源表名:a 目标表名:b Access可用
inrt into ba, b, c lect d,e,f from b;
3、说明:跨数据库之间表的拷贝具体数据使用绝对路径 Access可用
inrt into ba, b, c lect d,e,f from b in ‘具体数据库’ where 条件
例子:..from b in ‘"&"."&"" &"‘ where..
4、说明:子查询表名1:a 表名2:b
lect a,b,c from a where a IN lect d from b 或者: lect a,b,c from a
where a IN 1,2,3
5、说明:显示文章、提交人和最后回复时间
lect ,, from table a,lect maxadddate adddate from table where = b
6、说明:外连接查询表名1:a 表名2:b
lect , , , , , from a LEFT OUT JOIN b ON =
7、说明:在线视图查询表名1:a
lect from Select a,b,c FROM a T where > 1;
8、说明:between的用法,between限制查询数据范围时包括了边界值,not
between不包括
lect from table1 where time between time1 a新学期新气象板报
nd time2
lect a,b,c, from table1 where a not between 数值1 and 数值2
9、说明:in 的使用方法
lect from table1 where a not in ‘值1’,’值2’,’值4’,’值6’
10、说明:两张关联表,删除主表中已经在副表中没有的信息
delete from table1 where not exists lect from table2 where =
11、说明:四表联查问题:
lect from a left inner join b on = right inner join c on = inner join d on =
where .....
12、说明:日程安排提前五分钟提醒
SQL: lect from 日程安排 where datediff‘minute‘,f开始时
间,getdate>5
13、说明:一条sql 语句搞定数据库分页
lect top 10 b. from lect top 20 主键字段,排序字段 from 表名 order
by 排序字段 desc a,表名 b where b.主键字段 = a.主键字段 order by a.
排序字段
14、说明:前10条记录
lect top 10 form table1 where 范围
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有
信息类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科
目成绩排名,等等.
lect a,b,c from tablename ta where a=lect maxa from tablename tb
where =
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中茶话会主持词
的行并
消除所有重复行而派生出一个结果表
lect a from tableA except lect a from tableB except lect a from tableC
17、说明:随机取出10条数据
lect top 10 from tablename order by newid
18、说明:随机选择记录
lect newid
19、说明:删除重复记录
Delete from tablename where id not in lect maxid from 人力资源部门职责
tablename group
by col1,col2,...
20、说明:列出数据库里所有的表名
lect name from sysobjects where type=‘U‘
21、说明:列出表里的所有的
lect name from syscolumns where id=object_id‘TableName‘
22、说明:列示type、vender、pcs字段,以type字段排列,ca可以方便
地实现多重选择,类似lect 中的ca;
lect type,sumca vender when ‘A‘ then pcs el 0 end,sumca v旅游鞋清洗
ender
when ‘C‘ then pcs el 0 end,sumca vender when ‘B‘ then pcs el 0 end
FROM tablename group by type
显示结果:
type vender pcs
电脑 A 1
电脑 A 1
光盘 B 2
光盘 A 2
手机 B 3
手机 C 3
23、说明:初始化表table1
TRUNCATE TABLE table1
24、说明:选择从10到15的记录
lect top 5 from lect top 15 from table order by id asc table_别名
order by id desc
三、技巧
1、1=1,1=2的使用,在SQL语句组合时用的较多
“where 1=1” 是表示选择全部 “where 1=2”全部不选,
如:
if strWhere =‘
begin
t strSQL = ‘lect count as Total from ‘ + tblName + ‘ where ‘ + strWhere
end
el
begin
t strSQL = ‘lect cou中国茶的种类
nt as Total from ‘ + tblName + ‘‘
end
我们可以直接写成
t strSQL = ‘lect count as Total from ‘ + tblName + ‘ where 1=1 安定
‘+ strWhere
2、收缩数据库
--重建索引
DBCC REINDEX
DBCC INDEXDEFRAG
--收缩数据和日志
DBCC SHRINKDB
DBCC SHRINKFILE
3、压缩数据库
dbcc shrinkdatabadbname
4、转移数据库给新用户以已存在用户权限
exec sp_change_urs_login ‘update_one‘,‘newname‘,‘oldname‘
go
5、检查备份集
RESTORE VERIFYONLY from disk=‘E:‘
6、修复数据库
Alter DATABASE dvbbs SET SINGLE_USER
GO
DBCC CHECKDB‘dvbbs‘,repair_allow_data_loss WITH TABLOCK
GO
Alter DATABASE dvbbs SET MULTI_USER
GO
7、日志清除
SET NOCOUNT ON
DECLARE LogicalFileName sysname,
MaxMinutes INT,
NewSize INT
USE tablename -- 要操作的数据库名
Select LogicalFileName = ‘tablename_log‘, -- 日志文件名
MaxMinutes = 10, -- Limit on time allowed to wrap log.
NewSize = 1 -- 你想设定的日志文件的大小M
-- Setup / initialize
DECLARE OriginalSize int
Select OriginalSize = size
FROM sysfiles
Where name = LogicalFileName
Select ‘Original Size of ‘ + db_name + ‘ LOG is ‘ +
CONVERTVARCHAR30,OriginalSize + ‘ 8K pages or ‘ +
CONescape1
VERTVARCHAR30,OriginalSize8/1024 + ‘MB‘
FROM sysfiles
Where name = LogicalFileName
Create TABLE DummyTrans
DummyColumn char 8000 not null
DECLARE Counter INT,
StartTime DATETIME,
TruncLog VARCHAR255
Select StartTime = GETDATE,
TruncLog = ‘BACKUP LOG ‘ + db_name + ‘ WITH TRUNCATE_ONLY‘
DBCC SHRINKFILE LogicalFileName, NewSize
EXEC TruncLog
-- Wrap the log if necessary.
WHILE MaxMinutes > DATEDIFF mi, StartTime, GETDATE -- time has
not expired
AND OriginalSize = Select size FROM sysfiles Where name =
LogicalFileName
AND OriginalSize 8 /1024 > NewSize
BEGIN -- Outer loop.
Select Counter = 0
WHILE Counter < OriginalSize / 16 AND Counter < 50000
BEGIN -- update
Inrt DummyTrans VALUES ‘Fill Log‘
Delete DummyTrans
Select Counter = Counter + 1
END
EXEC TruncLog
END
Select ‘Final Size of ‘ + db_name + ‘ LOG is ‘ +
CONVERTVARCHAR30,size + ‘ 8K pages or ‘ +
CONVERTVARCHAR30,size8/1024 + ‘MB‘
FROM sysfiles
Where name = LogicalFileName
Drop TABLE DummyTrans
SET NOCOUNT OFF
8、说明:更改某个表
exec sp_changeobjectowner ‘tablename‘,‘dbo‘
9、存储更改全部表
Create PROCEDURE
OldOwner as NVARCHAR128,
NewOwner as NVA人们英语
RCHAR128
AS
DECLARE Name as NVARCHAR128
DECLARE Owner as NVARCHAR128
DECLARE OwnerName as NVARCHAR128
DECLARE curObject CURSOR FOR
lect ‘Name‘ = name,
‘Owner‘ = ur_nameuid
from sysobjects
where ur_nameuid=OldOwner
order by name
OPEN curObject
FETCH NEXT FROM curObject INTO Name, Owner
WHILEFETCH_STATUS=0
BEGIN
if Owner=OldOwner
begin
t OwnerName = OldOwner + ‘.‘ + rtrimName
exec sp_changeobjectowner OwnerName, NewOwner
end
-- lect name,NewOwner,OldOwner
FETCH NEXT FROM curObject INTO Name, Owner
END
clo curObject
deallocate curObject
GO
10、SQL SERVER中直接循环写入数据
declare i int
t i=1
while i<30
begin
inrt into test urid valuesi
t i=i+1
end