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。 .;I29yk\XS
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一、基础 zg}YGu|J
1、说明:创建数据库 >bm|%Ou"
CREATE DATABASE database-name $\\lx_)
2、说明:删除数据库 }NmNanW^
drop database dbname -|_ir-j
3、说明:备份sql server &a)vdlZSE=
--- 创建 备份数据的 device ae`|ic
USE master }GZbo kWg.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' r|R7-HI
--- 开始 备份 k DsIp=
BACKUP DATABASE pubs TO testBack i g71/'D
4、说明:创建新表 bI
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `rFAZcEj%
根据已有的表创建新表: #}yTDBt
A:create table tab_new like tab_old (使用旧表创建新表) \C|cp|A*&
B:create table tab_new as select col1,col2... from tab_old definition only 1(gfdx9|b
5、说明:删除新表 vv5i? F
drop table tabname #G;X' BN
6、说明:增加一个列 9K"JYJ
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Alter table tabname add column col type ;u-4KK
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 v1.*IV5Y
7、说明:添加主键: Alter table tabname add primary key(col) tL(B pL'
说明:删除主键: Alter table tabname drop primary key(col) o'=VZT9
8、说明:创建索引:create [unique] index idxname on tabname(col....) \U @3`
删除索引:drop index idxname *e4TSqC|
注:索引是不可更改的,想更改必须删除重新建。 n^9 ?~
9、说明:创建视图:create view viewname as select statement Fr:5$,At7-
删除视图:drop view viewname 4<v;1
10、说明:几个简单的基本的sql语句 ?p^2Z6J'$
选择:select * from table1 where 范围 CEtR[Cu
插入:insert into table1(field1,field2) values(value1,value2) VXKT\9g3A
删除:delete from table1 where 范围 `/:cfP\
更新:update table1 set field1=value1 where 范围 1/iE`Si
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! XD%wj
排序:select * from table1 order by field1,field2 [desc] cyF4iG'M,y
总数:select count as totalcount from table1 q)I|2~Q c^
求和:select sum(field1) as sumvalue from table1 ?d-70pm
平均:select avg(field1) as avgvalue from table1 kW-81
最大:select max(field1) as maxvalue from table1 8Qrpa o
最小:select min(field1) as minvalue from table1 ^R_e
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11、说明:几个高级查询运算词 b1^cD6sT+
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A: UNION 运算符 a6nlt?1?D
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。 `gguip-C
B: EXCEPT 运算符 Q,e*#oK3$
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。 @$U e$
C: INTERSECT 运算符 xFb3O|TC
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。 }~I|t!GL
注:使用运算词的几个查询结果行必须是一致的。 5h^[^*A?
12、说明:使用外连接 d-$_|G+
A、left outer join: <r\I"z$
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。 ZBM!MSf:
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 3H8Al
B:right outer join: ! D1zXXq
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。 A7Y_HIo
C:full outer join: ;z>p8N
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。 J$[Q?8
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二、提升 KwFXB
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 3,$iGe
法一:select * into b from a where 1<>1 qgexb\x\4
法二:select top 0 * into b from a z8iENECwj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8S>>7z!U
insert into b(a, b, c) select d,e,f from b; U[fSQ`&D
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) R^tcr)(
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 x0G>ktWq<
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. O/9fuEF
4、说明:子查询(表名1:a 表名2:b) L82NP)St
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) Zi1YZxF`Y
5、说明:显示文章、提交人和最后回复时间 fM:80bnL+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b k3yxx]Rk/
6、说明:外连接查询(表名1:a 表名2:b) JQT4N[rEE
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .^H1\p];Lw
7、说明:在线视图查询(表名1:a ) 'j#a%j@{
select * from (SELECT a,b,c FROM a) T where t.a > 1; -$R5
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 gKQ@!UU8
select * from table1 where time between time1 and time2 vKkf2 7
select a,b,c, from table1 where a not between 数值1 and 数值2 eT\p-4b
9、说明:in 的使用方法 hht+bpHl
select * from table1 where a [not] in ('值1','值2','值4','值6') "m>};.lj
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7'UWRRsxUF
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %zQ2:iT5@=
11、说明:四表联查问题: :SeLkQC
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Q9q9<J7j$
12、说明:日程安排提前五分钟提醒 C$y fMK,,N
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8;.` {'r
13、说明:一条sql 语句搞定数据库分页 h7RD`k:mF
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 i*A$SJ:}
14、说明:前10条记录 \S5V}!_
select top 10 * form table1 where 范围 ZjavD^ky
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.) ~ i'C/[P
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) LOt#1Qv
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 a;yV#Y
(select a from tableA ) except (select a from tableB) except (select a from tableC) w6v1 q:20
17、说明:随机取出10条数据 't ;/,+:V
select top 10 * from tablename order by newid() oHRbAE^
18、说明:随机选择记录 Bf(Mot^
select newid() +}Auk|>Dc
19、说明:删除重复记录 1W7
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 KK .cDAR
select name from sysobjects where type='U' E =
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21、说明:列出表里的所有的 MIJ%_=sm4:
select name from syscolumns where id=object_id('TableName') X)Ocn`|
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。 +@ ^47Xu^
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 *IVD/9/
显示结果: 0=gF6U
type vender pcs Y~x`6
电脑 A 1 ZS|Z98
电脑 A 1 B1HQz@^
光盘 B 2 '>4+WZ1w5
光盘 A 2 wfWS-pQ
手机 B 3 Mof)2Hbd:
手机 C 3 [lrmuf
23、说明:初始化表table1 ?WMi S]Q\
TRUNCATE TABLE table1 #{?m
24、说明:选择从10到15的记录 VQ/ <09e
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc hE9'F(87a
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三、技巧 R20a(4m
1、1=1,1=2的使用,在SQL语句组合时用的较多 0 [*nAo
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 60(}_%
如: H@Kl
if @strWhere !='' /0X0#+kn
begin ^ON-#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /QM0.{Ypl
end q^Q|.&_k /
else g%Th_= qy
begin Z5{*? 2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1"*Nb5s
end )^V5*#69D
我们可以直接写成 c4FOfH|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere hCSRsk3
2、收缩数据库 ghE?8&@ iq
--重建索引 -fx(H+
DBCC REINDEX 'Hcd&3a
DBCC INDEXDEFRAG rjhs?
--收缩数据和日志 a @yE:HU
DBCC SHRINKDB @$K![]oD
DBCC SHRINKFILE >Rx8 0
3、压缩数据库 ;+aDjO2(
dbcc shrinkdatabase(dbname) 3D[:Rf[
4、转移数据库给新用户以已存在用户权限 S5YDS|K
exec sp_change_users_login 'update_one','newname','oldname' 6x`\
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go n0
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5、检查备份集 ?];~N5<'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' #!K~_DL
6、修复数据库 #8WR{
ALTER DATABASE [dvbbs] SET SINGLE_USER :7 s#5b
GO u0(hVK`":
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK RBHqLg(
GO Ugee?;]lu
ALTER DATABASE [dvbbs] SET MULTI_USER ;mM\,
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GO &B{Jxc`VA
7、日志清除 3XYIb Xnk
SET NOCOUNT ON oIu,rjb
DECLARE @LogicalFileName sysname, ^$Me#ls!
@MaxMinutes INT, _bvtJZ3i
@NewSize INT [|P]St-
USE tablename -- 要操作的数据库名 Z7k1fv:S^
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "' i [~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. &6~ncQWu
@NewSize = 1 -- 你想设定的日志文件的大小(M) sOrY^cY;
-- Setup / initialize ;Wp`th!F
DECLARE @OriginalSize int cl9;2D"Zm!
SELECT @OriginalSize = size S^sW.(I
FROM sysfiles FB^dp}
WHERE name = @LogicalFileName 6:7:NI l:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _4x[}e7KF
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Qnu&GBM
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' R}K5'`[%ZY
FROM sysfiles x]jdx#'
WHERE name = @LogicalFileName -`ys pE0?
CREATE TABLE DummyTrans d$G%F $BTs
(DummyColumn char (8000) not null) N]P*6sf-6
DECLARE @Counter INT, NVM2\fs
@StartTime DATETIME, E6KBpQcd[
@TruncLog VARCHAR(255) SieV%T0t1
SELECT @StartTime = GETDATE(), ]jT[dX|?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' nms<6kfzL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) }E\+e!'!2
EXEC (@TruncLog) 3dzqVaV
-- Wrap the log if necessary. GE| ^ryh
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired dpOL1rrE
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) .4m3@!qo)E
AND (@OriginalSize * 8 /1024) > @NewSize Z ysUz
BEGIN -- Outer loop. qI/r_
SELECT @Counter = 0 A`ertSlbhe
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -|iA!w#31
BEGIN -- update ]oZ,{Q5~
INSERT DummyTrans VALUES ('Fill Log') 9p0HFri[
DELETE DummyTrans `OpC-Z&
SELECT @Counter = @Counter + 1 pU)3*9?cIl
END 0kr& c;~
EXEC (@TruncLog) JqV<A3i
END +^3L~?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + z@S8H6jM)S
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + sOtNd({
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1:l&&/Wy
FROM sysfiles z_iyuLRdb
WHERE name = @LogicalFileName ?+JxQlVDt-
DROP TABLE DummyTrans ^Y*.Ktp,o
SET NOCOUNT OFF *V<2\-
8、说明:更改某个表 4O,a`:d1$6
exec sp_changeobjectowner 'tablename','dbo' g7q]Vj
9、存储更改全部表 M#jee E-}%
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ng)yCa_Ny
@OldOwner as NVARCHAR(128), /r 2.j3:l
@NewOwner as NVARCHAR(128) -<^Q2]PE;
AS w+TuS).
DECLARE @Name as NVARCHAR(128) )(
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DECLARE @Owner as NVARCHAR(128) +OuG!3+w
DECLARE @OwnerName as NVARCHAR(128) yDBgSO{d
DECLARE curObject CURSOR FOR MM)/B>c Qt
select 'Name' = name, 4Fc1'
'Owner' = user_name(uid) 2o7C2)YT$
from sysobjects HC, 0"W
where user_name(uid)=@OldOwner o_+Qer=O6
order by name d:WhP_rK9
OPEN curObject Vy*Z"k
FETCH NEXT FROM curObject INTO @Name, @Owner -`1L[-<d=/
WHILE(@@FETCH_STATUS=0) YVV $g-D}
BEGIN cO?"
if @Owner=@OldOwner :s985sEv
begin 5|={1Lp24g
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2Mi;}J1C{
exec sp_changeobjectowner @OwnerName, @NewOwner I }I/dh
end `-`iS?
-- select @name,@NewOwner,@OldOwner |(8h:g
FETCH NEXT FROM curObject INTO @Name, @Owner 49kia!FR
END *X55:yha
close curObject 2gI_*fG1
deallocate curObject vF\zZ<R/
GO rKO*A7vE
10、SQL SERVER中直接循环写入数据 {Ag}P0%'
declare @i int HWAqJb [
set @i=1 $?Mz[X
while @i<30 u1Yp5jp^K
begin zt%Fvn4/pF
insert into test (userid) values(@i) u(a&x|WY
set @i=@i+1 ,H1~_|)<
end ~7H.<kJt
小记存储过程中经常用到的本周,本月,本年函数 uk/+
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Dateadd(wk,datediff(wk,0,getdate()),-1) 6)YNjh.{*
Dateadd(wk,datediff(wk,0,getdate()),6) z=pV{'
Dateadd(mm,datediff(mm,0,getdate()),0) p&M'DMj+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) BC[d={_-
Dateadd(yy,datediff(yy,0,getdate()),0) . +?lID
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) LP_F"?4
上面的SQL代码只是一个时间段 ><7`$ 2Or
Dateadd(wk,datediff(wk,0,getdate()),-1) D/`E!6Fk=
Dateadd(wk,datediff(wk,0,getdate()),6) .ai9PsZ?V
就是表示本周时间段. Mdh"G @$n
下面的SQL的条件部分,就是查询时间段在本周范围内的: /RmCMT
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) B+sqEj-
而在存储过程中 dEL"(e#0s4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .e+UgCwi
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WcG&W>