SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 F.=Bnw/-
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一、基础 V{&rQ@{W
1、说明:创建数据库 [mr9(m[F
CREATE DATABASE database-name m7GR[MR
2、说明:删除数据库 u=/CRjot
drop database dbname U*P. :BvG
3、说明:备份sql server *(>}Y
--- 创建 备份数据的 device &gE 75B
USE master mA@Me7m}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' "a/ Q%.P
--- 开始 备份 P7f,OY<@%o
BACKUP DATABASE pubs TO testBack (V% `k'N7f
4、说明:创建新表 FSbHn{@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) NwR}yb6
根据已有的表创建新表: Z@%HvB7
A:create table tab_new like tab_old (使用旧表创建新表) 9bq<GC'eX8
B:create table tab_new as select col1,col2... from tab_old definition only eDZ8w
5、说明:删除新表 &"mzwQX
drop table tabname Q;J`Q wkH
6、说明:增加一个列 ~w;]c_{.b
Alter table tabname add column col type %9#gB
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。 :BGA.
7、说明:添加主键: Alter table tabname add primary key(col) cl*PFQp9j
说明:删除主键: Alter table tabname drop primary key(col) @M8|(N%
8、说明:创建索引:create [unique] index idxname on tabname(col....) 2JS`Wqy
删除索引:drop index idxname r]Ff{la5
注:索引是不可更改的,想更改必须删除重新建。 @hImk`&[N
9、说明:创建视图:create view viewname as select statement fQ=MJ7l
删除视图:drop view viewname KyO8A2'U
10、说明:几个简单的基本的sql语句 EmT`YNuc
选择:select * from table1 where 范围 z5X~3s\dP
插入:insert into table1(field1,field2) values(value1,value2) z]bwnJfd
删除:delete from table1 where 范围 zn@N'R/
更新:update table1 set field1=value1 where 范围 (x$9~;<S*d
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |fY/i]
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排序:select * from table1 order by field1,field2 [desc] 34R!x6W0
总数:select count as totalcount from table1 zPKr/
求和:select sum(field1) as sumvalue from table1 @AYo-gf
平均:select avg(field1) as avgvalue from table1 =?(~aV
最大:select max(field1) as maxvalue from table1 `K
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最小:select min(field1) as minvalue from table1 oo$MWN8a>r
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11、说明:几个高级查询运算词 e%>b+Sv
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A: UNION 运算符 T4;T6 9j;,
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。 _ZAch zV
B: EXCEPT 运算符 )*d W=r/$V
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 sfVf@0g
C: INTERSECT 运算符 }Y17*zp%
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 xyE1Gw`V
注:使用运算词的几个查询结果行必须是一致的。 L~^*u_U]
12、说明:使用外连接 90Hjx>[
A、left outer join: 2w$twW-
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。 V8~jf-\$b
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Sj(F3wY
B:right outer join: STA4 p6
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。 *AIEl"29
C:full outer join: !"TZ:"VZU
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。 -gz0md|Y
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二、提升 N6[i{;K@N{
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Gj /3kS~@
法一:select * into b from a where 1<>1 jUqy8q&
法二:select top 0 * into b from a 6dEyv99
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) PZD>U)M
insert into b(a, b, c) select d,e,f from b; rB%$;<`/
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) #9LzY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ksjUr 1o
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t=#Pya
4、说明:子查询(表名1:a 表名2:b) \ U-vI:J_
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) il:nXpM!
5、说明:显示文章、提交人和最后回复时间 @oG)LT
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b mty1p'^KQ
6、说明:外连接查询(表名1:a 表名2:b) qUF1XJZ}z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Us~ X9n_F
7、说明:在线视图查询(表名1:a ) !z
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select * from (SELECT a,b,c FROM a) T where t.a > 1; qYp$fmj
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 Y#01o&f0n
select * from table1 where time between time1 and time2 8 )\M:s~7&
select a,b,c, from table1 where a not between 数值1 and 数值2 bO/*2oau
9、说明:in 的使用方法 ,goBq3[%?
select * from table1 where a [not] in ('值1','值2','值4','值6') W:QwHZ2O
10、说明:两张关联表,删除主表中已经在副表中没有的信息 C+MSVc
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) p&K\]l}
11、说明:四表联查问题: /MOnNnV
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 8"vwU@cfC
12、说明:日程安排提前五分钟提醒 >LF&EM]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !
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13、说明:一条sql 语句搞定数据库分页 e^$j5jV
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 H%z@h~s>
14、说明:前10条记录 .#5l$['
select top 10 * form table1 where 范围 &}`K^5K|O:
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.) aP>37s
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1{2eY%+C
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 !|m9|
(select a from tableA ) except (select a from tableB) except (select a from tableC) }+Vv0jX|V
17、说明:随机取出10条数据 Ca $c;
select top 10 * from tablename order by newid() RwTzz]
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18、说明:随机选择记录 X^@[G8v%
select newid() BZF,=v
19、说明:删除重复记录 }1%r%TikY
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) |[cdri^?D
20、说明:列出数据库里所有的表名 I&1!v8
select name from sysobjects where type='U' C/v}^#cLD
21、说明:列出表里的所有的 |&hU=J
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select name from syscolumns where id=object_id('TableName') 0D)`2W
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Z]-WFU_
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type s!6=|SS7
显示结果: p#_[
type vender pcs `!w^0kZ
电脑 A 1 04y!\
电脑 A 1 CM~MoV[k7e
光盘 B 2 LI:Tc7t
光盘 A 2 ur2!#bU9
手机 B 3 xKJ>gr"w#
手机 C 3 @5}gsC
23、说明:初始化表table1 LBX%H GH
TRUNCATE TABLE table1 Wtv#h~jy9
24、说明:选择从10到15的记录 <uF [,
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _q Tpy)+
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三、技巧 te2
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1、1=1,1=2的使用,在SQL语句组合时用的较多 '.p? 6k!K
"where 1=1" 是表示选择全部 "where 1=2"全部不选, BQjam+u6
如: Qm);6X
if @strWhere !='' Gidkt;lj
begin f:%SW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mpef]9
end T#iU+)-\%
else GFR!n1Hv
begin %N~;{!![p
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .u< U:*
end '>^Xqn
我们可以直接写成 "r-l8r,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |@`"F5@,
2、收缩数据库 *:arva5
--重建索引 Sa}D.SBg
DBCC REINDEX w4:<fnOM
DBCC INDEXDEFRAG \X@IkL$r
--收缩数据和日志 56s*A*z$
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DBCC SHRINKDB :k1$g+(lP
DBCC SHRINKFILE Z! YpklZ?~
3、压缩数据库 4
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dbcc shrinkdatabase(dbname) ULvVD6RQ47
4、转移数据库给新用户以已存在用户权限 &] 3:D
exec sp_change_users_login 'update_one','newname','oldname' yzc pG6,
go w<d*#$[,*
5、检查备份集 &`PbO
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' j+1KNH
6、修复数据库 YkbO&~.
ALTER DATABASE [dvbbs] SET SINGLE_USER DM2Q1Dh3
GO YZ[%uArm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK R|t;p!T
GO # ,P(isEZ"
ALTER DATABASE [dvbbs] SET MULTI_USER Gj`f--2GE
GO Ve14rn
7、日志清除 kGD|c=K}
SET NOCOUNT ON mG}k 3e-
DECLARE @LogicalFileName sysname, /;+,mp4
@MaxMinutes INT, :GM#&*$2<
@NewSize INT *tAqt2{48
USE tablename -- 要操作的数据库名 =8S}Iat
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1b`G2?%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. &PWf:y{R`
@NewSize = 1 -- 你想设定的日志文件的大小(M) x<Se>+
-- Setup / initialize {Tx 3$eU
DECLARE @OriginalSize int K.h]JD]o
SELECT @OriginalSize = size Fd"WlBYy0
FROM sysfiles f%1wMOzx
WHERE name = @LogicalFileName $SF3odpt
SELECT 'Original Size of ' + db_name() + ' LOG is ' + GI4oQcJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + HWR&C
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' k6g|7^es2
FROM sysfiles 4(iS-8{J
WHERE name = @LogicalFileName 7z>+w
CREATE TABLE DummyTrans L{K*~B -p
(DummyColumn char (8000) not null) 4JK@<GBK6
DECLARE @Counter INT, 2))t*9;h
@StartTime DATETIME, KW:r;BFx
@TruncLog VARCHAR(255) !pS~'E&q
SELECT @StartTime = GETDATE(), )]]|d
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' g _x\T+=
DBCC SHRINKFILE (@LogicalFileName, @NewSize) w#d} TY
EXEC (@TruncLog) .9I_NG
-- Wrap the log if necessary. 2HVCXegq
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired G,/Gq+WX
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 9!S^^;PN&
AND (@OriginalSize * 8 /1024) > @NewSize k7b(QADqUU
BEGIN -- Outer loop. 9T]va]w?#
SELECT @Counter = 0 &}|0CR.(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4Qhx[Hv>(
BEGIN -- update |N6mTB2
INSERT DummyTrans VALUES ('Fill Log') m^c%]5$
DELETE DummyTrans ^s.oZj
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SELECT @Counter = @Counter + 1 ec`>KuY
END 8ipW3~-4
EXEC (@TruncLog) z,os
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END 9`,,%vdj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + C*]AL/
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,FS?"Ni
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T*p|'Q`
FROM sysfiles _dY:)%[]
WHERE name = @LogicalFileName o8mo=V4j
DROP TABLE DummyTrans $;ch82UiX
SET NOCOUNT OFF H WOek"}Z[
8、说明:更改某个表 kEx8+2s=M
exec sp_changeobjectowner 'tablename','dbo' 0vcET(
9、存储更改全部表 i~ROQMN1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch taBO4LV
@OldOwner as NVARCHAR(128), 3lyQn"
@NewOwner as NVARCHAR(128) _i.({s&_9
AS tc5M$b3^2
DECLARE @Name as NVARCHAR(128) AtuZF
DECLARE @Owner as NVARCHAR(128) wbl${@4
DECLARE @OwnerName as NVARCHAR(128) 8\P
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DECLARE curObject CURSOR FOR i:R!T,
select 'Name' = name, "{mt?
'Owner' = user_name(uid) oNrEIgaA(+
from sysobjects Ep,1}Dx
where user_name(uid)=@OldOwner Za34/ro/T
order by name -wBnwn-
OPEN curObject Y<de9Z@
FETCH NEXT FROM curObject INTO @Name, @Owner IZ|c<#r6
WHILE(@@FETCH_STATUS=0) dV$3u"9
BEGIN "C?:T'dW
if @Owner=@OldOwner rkbl/py
begin G)jG!`I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [6oq##
exec sp_changeobjectowner @OwnerName, @NewOwner IBzHR[#,^
end O5c_\yv=
-- select @name,@NewOwner,@OldOwner EP/&m|o|G
FETCH NEXT FROM curObject INTO @Name, @Owner 5wy;8a
END fHW-Je7mG
close curObject %!>k#F^S
deallocate curObject fdg[{T4:
GO XlE$.
10、SQL SERVER中直接循环写入数据 osI- o~#>
declare @i int jg7d7{{SB
set @i=1 `x5ll;"J
while @i<30 u_h=nk
begin #^"hqNwA
insert into test (userid) values(@i) (}VuiNY<