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。 e
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一、基础 9On0om>
1、说明:创建数据库 _#SCjFz
CREATE DATABASE database-name dYEsSFB m
2、说明:删除数据库 MnQ4,+ji-
drop database dbname vi4lmkyh^
3、说明:备份sql server -;i vBR
--- 创建 备份数据的 device MYmH?A
USE master LdPA`oI3j
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8B*XXFy\
--- 开始 备份 BDO]-y
BACKUP DATABASE pubs TO testBack Im<i.a
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4、说明:创建新表 RqONVytx
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iB1+4wa
根据已有的表创建新表: "u H VX|`
A:create table tab_new like tab_old (使用旧表创建新表) :/.SrkN(A7
B:create table tab_new as select col1,col2... from tab_old definition only ~8j4IO(
5、说明:删除新表 .#4;em%7
drop table tabname =B/Ac0Y
6、说明:增加一个列 )R- e^Cb
Alter table tabname add column col type kdam]L:9
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。 L]syDn
7、说明:添加主键: Alter table tabname add primary key(col) 5, j&-{0W
说明:删除主键: Alter table tabname drop primary key(col) 2qN|<S&
8、说明:创建索引:create [unique] index idxname on tabname(col....) C<T)'^7z
删除索引:drop index idxname w.:fl4V
注:索引是不可更改的,想更改必须删除重新建。 kf Xg\6uKc
9、说明:创建视图:create view viewname as select statement QMI6l'"s
删除视图:drop view viewname ]bui"-tlK
10、说明:几个简单的基本的sql语句 ;ATn&
选择:select * from table1 where 范围 _
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插入:insert into table1(field1,field2) values(value1,value2) ]9 ArT$
删除:delete from table1 where 范围 D2@J4;UW*W
更新:update table1 set field1=value1 where 范围 O 8\wH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )[Bl3+'
排序:select * from table1 order by field1,field2 [desc] mj!P
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总数:select count as totalcount from table1 uQ_s$@brI
求和:select sum(field1) as sumvalue from table1 _'.YC<;
平均:select avg(field1) as avgvalue from table1 *oW^P~m/
最大:select max(field1) as maxvalue from table1 mDG=h6y"V
最小:select min(field1) as minvalue from table1 hb,G'IU
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11、说明:几个高级查询运算词 T+q3]&
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A: UNION 运算符 "h84D&V
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 G(*7hs
B: EXCEPT 运算符 |_H{B+.
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 O^_$cq
C: INTERSECT 运算符 fPj*qi
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。 9?6]Zag
注:使用运算词的几个查询结果行必须是一致的。 W,53|9b@
12、说明:使用外连接 Wb;x
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A、left outer join: k/`WfSM\.
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。 <jk.9$\$A
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 6%^9`|3
B:right outer join: Vi5&%/Y
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。 R|,F C'
C:full outer join: $Rd]eC
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。 RoY"Haa
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二、提升 ?!{nN J
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?%]?#4bkc
法一:select * into b from a where 1<>1 mD]^a;U[X
法二:select top 0 * into b from a 8euh]+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Z4ZR]eD
insert into b(a, b, c) select d,e,f from b; _l$1@
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) WNa#X]*E)
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Fb^Ae6/i
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4Up3x+bg
4、说明:子查询(表名1:a 表名2:b) Aq5@k\[
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) jWX^h^n7K
5、说明:显示文章、提交人和最后回复时间 :8CYTEc
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ev)aXP
6、说明:外连接查询(表名1:a 表名2:b) \U\k$ (
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7Gs0DwV
7、说明:在线视图查询(表名1:a ) ;/-X;!a>
select * from (SELECT a,b,c FROM a) T where t.a > 1; 1f/8XxTB
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 KD*q|?Z
select * from table1 where time between time1 and time2 F,NS:mE
select a,b,c, from table1 where a not between 数值1 and 数值2 ss4<s
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9、说明:in 的使用方法 flr&+=1?D
select * from table1 where a [not] in ('值1','值2','值4','值6') qUuvM
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %(v<aEQtt
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @9}SHS
11、说明:四表联查问题: !vQDPLBL
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 ..... 4pw:O^v
12、说明:日程安排提前五分钟提醒 Rc.8j,]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 x#0B
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13、说明:一条sql 语句搞定数据库分页 efnj5|JSV
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 G#(+p|n
14、说明:前10条记录 Q*c |!<
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select top 10 * form table1 where 范围 M .J
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.) .o_?n.H'&
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) eN?:3cP#l
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 sO;]l"{<
(select a from tableA ) except (select a from tableB) except (select a from tableC) }8\"oA6
17、说明:随机取出10条数据 =JK# "'
select top 10 * from tablename order by newid() |TE\ ]
18、说明:随机选择记录 6Y-sc*5
select newid() Q&;d7A.@
19、说明:删除重复记录 i(pevu
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (46S^*
20、说明:列出数据库里所有的表名 |-'.\)7:
select name from sysobjects where type='U' 1 xu2$x.b
21、说明:列出表里的所有的 &qP@WFl
select name from syscolumns where id=object_id('TableName') J ;e/S6l
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 gL-\@4\wc
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type d O' apey
显示结果: y9@DlK
type vender pcs w-3 B~e
电脑 A 1 S$egsK"~
电脑 A 1 Ts~)0
光盘 B 2 tc%0yr9
光盘 A 2 !~5=tK
手机 B 3 A[mm_+D>
手机 C 3 (8?5REz
23、说明:初始化表table1 w]Fi:kV
TRUNCATE TABLE table1 c~=yD:$
24、说明:选择从10到15的记录 0s%rd>3
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc } F; Nh7?
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三、技巧 %w0Vf$
1、1=1,1=2的使用,在SQL语句组合时用的较多 (q|EC;
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [L+VvO%cT
如: q&y9(ZvI
if @strWhere !='' 0u7\*Iy
begin :: 2pDtMS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere nRL2Z5iO-
end W2CQk
else TM1D|H
begin $!-a)U,w$B
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ktMUTL(B
end 4qc0QA%
我们可以直接写成 M^$liS.D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere w' gKE'c
2、收缩数据库 V.8pxD5s
--重建索引 mn;Wqb/
DBCC REINDEX ,aLdW,<6
DBCC INDEXDEFRAG 0k7kmDW
--收缩数据和日志 ~=pAy>oV
DBCC SHRINKDB 3 IK+&hk
DBCC SHRINKFILE VSJ08Ngi
3、压缩数据库 V,W":&!x
dbcc shrinkdatabase(dbname) B,]:<1l~
4、转移数据库给新用户以已存在用户权限 ,7{}}l
exec sp_change_users_login 'update_one','newname','oldname' df$VC
go '+Gy)@c
5、检查备份集 U $ bLt
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' |k-IY]6
6、修复数据库 :d5fU:
ALTER DATABASE [dvbbs] SET SINGLE_USER N+[ |"v
GO D]h~\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO 6}>:sr
ALTER DATABASE [dvbbs] SET MULTI_USER !_|rVg.
GO k\J 6WT
7、日志清除 9j6
SET NOCOUNT ON > 10pk
DECLARE @LogicalFileName sysname, .vbUv3NI
@MaxMinutes INT, (6WSQqp
@NewSize INT S/XkxGZ2
USE tablename -- 要操作的数据库名 O [81nlhS0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !83N.
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. KC`~\sYRN]
@NewSize = 1 -- 你想设定的日志文件的大小(M) f4k\hUA
-- Setup / initialize c_33.i"I}
DECLARE @OriginalSize int `PY>p!E
SELECT @OriginalSize = size u,rieKYF
FROM sysfiles o.Jq1$)~y
WHERE name = @LogicalFileName [9O,C-Mk
SELECT 'Original Size of ' + db_name() + ' LOG is ' + xzRs;AXOp
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2EdKxw3$]
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^6Std
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FROM sysfiles t#p*{S 3u
WHERE name = @LogicalFileName hjgxCSp
CREATE TABLE DummyTrans l*yh(3~}
(DummyColumn char (8000) not null) A>c/q&WUk
DECLARE @Counter INT, >;;tX3(
@StartTime DATETIME, _c W(R,i
@TruncLog VARCHAR(255) 6.!3g(w
SELECT @StartTime = GETDATE(), 9b0M'x'W5
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' M_4:~&N$
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $)5-}NJf'
EXEC (@TruncLog) 5G-}'-R
-- Wrap the log if necessary. !Hk$ t
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired LcA~ a<_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }#rdMh
AND (@OriginalSize * 8 /1024) > @NewSize 9_6.%qj&
BEGIN -- Outer loop. \G}$+
SELECT @Counter = 0 DB^"iof
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) V`n;W6Q17
BEGIN -- update -UPlQL
INSERT DummyTrans VALUES ('Fill Log') 3]X9 z
DELETE DummyTrans Ifc}=:nr
SELECT @Counter = @Counter + 1 l{{wrU`
END
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EXEC (@TruncLog) RRNoX}
END QqC4g]
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Eoj 2l&\
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + iuX82z`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1xJc[q
FROM sysfiles 4+V+SD
WHERE name = @LogicalFileName 5nGDt~a
DROP TABLE DummyTrans 8%$Vj
SET NOCOUNT OFF WB=pRC@
8、说明:更改某个表 4[ S0~O{r
exec sp_changeobjectowner 'tablename','dbo' g 36\%L
9、存储更改全部表 xF+a.gAIb
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ;Ly(O'9
@OldOwner as NVARCHAR(128), @R|Gz/
@NewOwner as NVARCHAR(128) CTbz?Kn
AS %("Bq"Q8
DECLARE @Name as NVARCHAR(128) 4)BPrWea1
DECLARE @Owner as NVARCHAR(128) Y]5\%JR
DECLARE @OwnerName as NVARCHAR(128) zKi5e+\
DECLARE curObject CURSOR FOR J#0oL_xY#
select 'Name' = name, C^hHt,&
'Owner' = user_name(uid) EzDj,!!<w
from sysobjects `J>76WN
where user_name(uid)=@OldOwner ;?y*@*2u
order by name _d$0(
OPEN curObject &?@gUk74"
FETCH NEXT FROM curObject INTO @Name, @Owner 6;lJs,I1w{
WHILE(@@FETCH_STATUS=0) PC_#kz
BEGIN ? 9.V@+i
if @Owner=@OldOwner p<|I!n&9
begin #nE%.k|R~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) z|Hc=AU8y
exec sp_changeobjectowner @OwnerName, @NewOwner FA.h?yfr
end Q}J'S5%
-- select @name,@NewOwner,@OldOwner %0PdN@I
FETCH NEXT FROM curObject INTO @Name, @Owner &AMW?vO
END ZwLD7j*)
close curObject b"ypS7
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deallocate curObject n.{+\M6k
GO u7=jtB
10、SQL SERVER中直接循环写入数据 VK*2`Z1
declare @i int H:X=v+W
set @i=1 VWlOMqL995
while @i<30 U8Pnt|0 M
begin R;P>_ei(LK
insert into test (userid) values(@i) <"uT=]wZ=
set @i=@i+1 o@`&
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$
end %"Y7 b2pPa
小记存储过程中经常用到的本周,本月,本年函数 jhWNMu
Dateadd(wk,datediff(wk,0,getdate()),-1) FQR{w
Dateadd(wk,datediff(wk,0,getdate()),6) 8?GS :+
Dateadd(mm,datediff(mm,0,getdate()),0)
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^N!l$&=
Dateadd(yy,datediff(yy,0,getdate()),0) g& yR -
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) c3gy{:lb
上面的SQL代码只是一个时间段 M-!eL<
Dateadd(wk,datediff(wk,0,getdate()),-1) y(K?mtQ
Dateadd(wk,datediff(wk,0,getdate()),6) zfE;)K^"
就是表示本周时间段. aW8Bx\q
下面的SQL的条件部分,就是查询时间段在本周范围内的: ?-g=Rfpag
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) y)W.xR
而在存储过程中 Ge+&C RhyX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ZDZPJp,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {d\erG(