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。 !SVW}Q=5#
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一、基础 ~d28"p.7
1、说明:创建数据库 *_U
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CREATE DATABASE database-name QD7>S(p
2、说明:删除数据库 uI.4zbgl[
drop database dbname 'M YqCfIK
3、说明:备份sql server _Tev503
--- 创建 备份数据的 device -0lpsF
USE master O=ci"2!\-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' g`\Vy4w
--- 开始 备份 |qfnbi-\
BACKUP DATABASE pubs TO testBack D`iWf3a.
4、说明:创建新表 L[<MBgFKv
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SrU,-mA W
根据已有的表创建新表: <4^a(Zh
A:create table tab_new like tab_old (使用旧表创建新表) )6Z)z;n]aW
B:create table tab_new as select col1,col2... from tab_old definition only 3
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5、说明:删除新表 !i{@B
drop table tabname nbhx2@Teqe
6、说明:增加一个列 n0nkv[
Alter table tabname add column col type 9v0f4Pbxm
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。 HH8a"Hq)
7、说明:添加主键: Alter table tabname add primary key(col) _/7[=e}y
说明:删除主键: Alter table tabname drop primary key(col) tlG&PVvr
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;v#~o*
删除索引:drop index idxname fH}`
注:索引是不可更改的,想更改必须删除重新建。 n6
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9、说明:创建视图:create view viewname as select statement HA"LU;5>2J
删除视图:drop view viewname vBq2JJAl
10、说明:几个简单的基本的sql语句 P6;L\9=H<
选择:select * from table1 where 范围 6<FJ`l]U9
插入:insert into table1(field1,field2) values(value1,value2) [K%Jt
删除:delete from table1 where 范围 [JsQ/|=z
更新:update table1 set field1=value1 where 范围 lLoFM
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uflp4_D
排序:select * from table1 order by field1,field2 [desc] 2=u5N[*
总数:select count as totalcount from table1 4d[:{/+Q
求和:select sum(field1) as sumvalue from table1 KG)Y{-Ao
平均:select avg(field1) as avgvalue from table1 *T*MLD]Q
最大:select max(field1) as maxvalue from table1 H|==i2V{
最小:select min(field1) as minvalue from table1 UP%X`
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11、说明:几个高级查询运算词 J1&G1\G|s=
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A: UNION 运算符 2~~Q NWN
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。 z&9vKF
B: EXCEPT 运算符 sm/l'e
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。 ;%hlh)k$
C: INTERSECT 运算符 : E]A51
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。 m3K8hL/
注:使用运算词的几个查询结果行必须是一致的。 5>"-lB &
12、说明:使用外连接 Mt<TEr}7Z=
A、left outer join: 592q`m\
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。 f GY. +W_
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 0|HD(d`a
B:right outer join: qzsS"=5
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。 pOpie5)7X
C:full outer join: v6TH-
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。 [P,1UO|$B
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二、提升 ]hN%~
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A1>R8Zuhy
法一:select * into b from a where 1<>1 {}{|trr-E
法二:select top 0 * into b from a oF)+f4
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) / IAK'/
insert into b(a, b, c) select d,e,f from b; YM/^-[k3
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 5(tOQ%AQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 lRX*\M\`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) f
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) qP *$wKY,
5、说明:显示文章、提交人和最后回复时间 bY&s$Ry3"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #*1\h=bzmW
6、说明:外连接查询(表名1:a 表名2:b) 'l!tQD!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c p 8Ts5n
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; gfFP-J3cN
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ZSU;>&>%v
select * from table1 where time between time1 and time2 qbFzA
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select a,b,c, from table1 where a not between 数值1 and 数值2 _h M3p
9、说明:in 的使用方法 +Q8Bin
select * from table1 where a [not] in ('值1','值2','值4','值6') rG}o!I`z
10、说明:两张关联表,删除主表中已经在副表中没有的信息 pkM_ @K
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) '$UlJDZ
11、说明:四表联查问题: cdf8YN0!
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 ..... =0MW+-
12、说明:日程安排提前五分钟提醒 #p6#,PZ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 aB#qzrr['8
13、说明:一条sql 语句搞定数据库分页 (KK9/k
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 #=q)>+\
14、说明:前10条记录 "#qyX[\
select top 10 * form table1 where 范围 Ks{^R`Oau
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.) M~zdcVTbH
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 4JT9EKo
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 K.dgQ-vn
(select a from tableA ) except (select a from tableB) except (select a from tableC) %, XyhS5[o
17、说明:随机取出10条数据 yv[s)c}
select top 10 * from tablename order by newid() ^kzw/.I{
18、说明:随机选择记录 Cn[`]
select newid() U8\[8~Xftn
19、说明:删除重复记录 w f,7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) eICk}gfun
20、说明:列出数据库里所有的表名 m("!
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select name from sysobjects where type='U' Jx[IHE
21、说明:列出表里的所有的 ZBB^?FF
select name from syscolumns where id=object_id('TableName') { P&l`
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。 LTm2B_+
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 .UU BAyjm
显示结果: oZA?}#DRl
type vender pcs K\`L>B. 1
电脑 A 1 mflH &Bx9
电脑 A 1 ?Xx,[Z&
光盘 B 2 /q ;MihK
光盘 A 2 0~<d<a -@
手机 B 3 w q% 4'(
手机 C 3 a#nVRPU8m
23、说明:初始化表table1 A_muuOIcI
TRUNCATE TABLE table1 YJ'h=!p}G
24、说明:选择从10到15的记录 \8'fy\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc e #>wv]V
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三、技巧 .Qn54tS0q
1、1=1,1=2的使用,在SQL语句组合时用的较多 O\,n;oj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [u[F6Wst
如: l23_K7
if @strWhere !='' /o*r[g7<
begin D ?1$I0 =
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere xVao3+r
end \`-/\N
else Ig-9Y;hdmn
begin HcXyU/>D
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Rf+ogLa=
end %`t;5kmR
我们可以直接写成 @V
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ]!E|5=q
2、收缩数据库 ^z-e"
--重建索引 R+
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DBCC REINDEX "6Hka{
DBCC INDEXDEFRAG CLg;
--收缩数据和日志 >?ZH[A
DBCC SHRINKDB h3$.`
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DBCC SHRINKFILE 7?:7}xb-
3、压缩数据库
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dbcc shrinkdatabase(dbname) %=xR$<D
4、转移数据库给新用户以已存在用户权限 o$FqMRep
exec sp_change_users_login 'update_one','newname','oldname' )q&=x2`
go snT! 3t
5、检查备份集 +R@5e+auQ.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' K'+GK S7.
6、修复数据库 0K <@?cI
ALTER DATABASE [dvbbs] SET SINGLE_USER ? "]fGp6y
GO Jtnuo]{R
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $?YRy_SI
GO <03 @c s
ALTER DATABASE [dvbbs] SET MULTI_USER ?g+0S@{i $
GO UQgOtqL3
7、日志清除 WBFG_])
SET NOCOUNT ON @%q0fj8b
DECLARE @LogicalFileName sysname, lR\=] ]7I>
@MaxMinutes INT, 6UXa
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@NewSize INT (Hb
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USE tablename -- 要操作的数据库名 8zS't2
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 X2hV)8Sk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. x]&V7Y
@NewSize = 1 -- 你想设定的日志文件的大小(M) $`W.9
-- Setup / initialize WX&Man!f
DECLARE @OriginalSize int WHk/Rg%<
SELECT @OriginalSize = size axW3#3#`
FROM sysfiles rl qn39
WHERE name = @LogicalFileName =/&ob%J)9]
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4#MvOjA5[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + dVmI.A'nbp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' PsU.dv[
FROM sysfiles POwJhT
WHERE name = @LogicalFileName QijEb
CREATE TABLE DummyTrans $m] ~d6
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, cVv+,l4V0
@StartTime DATETIME, p&ytUTna
@TruncLog VARCHAR(255) 8'Sw?FbVA/
SELECT @StartTime = GETDATE(), .%j(!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' H)(@A W+-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) P/5bNK!
EXEC (@TruncLog) Xm`jD'G
-- Wrap the log if necessary. R|
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Y[k%<f
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) HUiW#x%;
AND (@OriginalSize * 8 /1024) > @NewSize vi')-1Y
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BEGIN -- Outer loop. w'oP{=y[
SELECT @Counter = 0 1H`T=:P?
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6*u#^">,<
BEGIN -- update t33/QW
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INSERT DummyTrans VALUES ('Fill Log') *9M 5'
DELETE DummyTrans 'L4@|c~x
SELECT @Counter = @Counter + 1 mO;X>~K
END t<mT=(zt*
EXEC (@TruncLog) ;A7HEx
END R
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + OQ;'Xo
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Oaf!\z}
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' I9O!CQCTt
FROM sysfiles +O>!x#)&"
WHERE name = @LogicalFileName ,TPNsz|Q
DROP TABLE DummyTrans s1.YH?A;
SET NOCOUNT OFF S G|``}OA
8、说明:更改某个表 Tu2BQ4\[
exec sp_changeobjectowner 'tablename','dbo' Fn.wd`'0
9、存储更改全部表 E,&BP$B
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ig:,: KN
@OldOwner as NVARCHAR(128), A ^@:Ps
@NewOwner as NVARCHAR(128) P -0
AS 9r=@S
DECLARE @Name as NVARCHAR(128) ikf!7-,
DECLARE @Owner as NVARCHAR(128) L/dG0a@1X
DECLARE @OwnerName as NVARCHAR(128) H)S" `j
DECLARE curObject CURSOR FOR 2V%si 6
select 'Name' = name, ${Cb1|g>j
'Owner' = user_name(uid) >Vz Gx(7q
from sysobjects (~}IoQp>
where user_name(uid)=@OldOwner %tEjf
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order by name [<`K%1GQ
OPEN curObject )/kkvI()l
FETCH NEXT FROM curObject INTO @Name, @Owner +U_> Bo
WHILE(@@FETCH_STATUS=0) S'm&Ll2i@
BEGIN G,I[zhX\
if @Owner=@OldOwner a]XQM$T$
begin c+chwU0W
set @OwnerName = @OldOwner + '.' + rtrim(@Name) t &XH:w&j
exec sp_changeobjectowner @OwnerName, @NewOwner o"dX3jd
end w=5 D>]
-- select @name,@NewOwner,@OldOwner X-&t!0O4}`
FETCH NEXT FROM curObject INTO @Name, @Owner #
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END b-R!oP+vP
close curObject ~H!s{$.5
deallocate curObject '0)a|1,
GO ,{P*ZK3u
10、SQL SERVER中直接循环写入数据 #s'9Ydd
declare @i int UUi@
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set @i=1 GADb Xp3
while @i<30 LN}eD\
begin Nr)v!z~y
insert into test (userid) values(@i) ][3H6T!ckL
set @i=@i+1 |;3Ru vX?+
end ={,\6a|]:
小记存储过程中经常用到的本周,本月,本年函数 ?;Dh^mc
Dateadd(wk,datediff(wk,0,getdate()),-1) / 4{6`
Dateadd(wk,datediff(wk,0,getdate()),6) 'X&sH/>r
Dateadd(mm,datediff(mm,0,getdate()),0) YCZl1ry:V=
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) cr Hd$~q,
Dateadd(yy,datediff(yy,0,getdate()),0) [mX/]31
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) }9yAYZ0q{b
上面的SQL代码只是一个时间段 )7@f{E#w
Dateadd(wk,datediff(wk,0,getdate()),-1) Lt>"R! "x
Dateadd(wk,datediff(wk,0,getdate()),6) ^]:w5\DG
就是表示本周时间段. LdxrS5
下面的SQL的条件部分,就是查询时间段在本周范围内的: /.{4
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8sb<$M$c
而在存储过程中 zvv<w@rX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Im7<\ b@