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。 8z,i/:
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一、基础 FCO5SX#-g
1、说明:创建数据库 7+^9"k7
CREATE DATABASE database-name F<SCW+>z2a
2、说明:删除数据库 ma4Pmk
drop database dbname Om
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3、说明:备份sql server 5:[<pY!s#
--- 创建 备份数据的 device ^@W98_bd;
USE master gT 8^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' } Ej^M~Vv
--- 开始 备份 00s&<EM
BACKUP DATABASE pubs TO testBack #=6A[<qX
4、说明:创建新表 8&?kr/_Vr
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Vq[L4
根据已有的表创建新表: GJlkEWs
A:create table tab_new like tab_old (使用旧表创建新表) r8PXdNg
B:create table tab_new as select col1,col2... from tab_old definition only ;uw`6 KJ
5、说明:删除新表 wk
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drop table tabname eK]g FXk
6、说明:增加一个列 M#v#3:&5
Alter table tabname add column col type 8S;]]*cD~
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。 ;O8Uc&:P
7、说明:添加主键: Alter table tabname add primary key(col) m e\S:
说明:删除主键: Alter table tabname drop primary key(col) l!Bc0
8、说明:创建索引:create [unique] index idxname on tabname(col....) :=J~t@
删除索引:drop index idxname aDJ\%
注:索引是不可更改的,想更改必须删除重新建。 lgR;V]^YX
9、说明:创建视图:create view viewname as select statement }` &an$Mu
删除视图:drop view viewname Yt^<^l77D
10、说明:几个简单的基本的sql语句 ym*,X@Qg^
选择:select * from table1 where 范围 (#zSVtZ
插入:insert into table1(field1,field2) values(value1,value2) $@
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删除:delete from table1 where 范围 b-sbR R
更新:update table1 set field1=value1 where 范围 "zU}]|R
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1<Vc[p&
排序:select * from table1 order by field1,field2 [desc] Z0yy<9q]2
总数:select count as totalcount from table1 ?_S f
求和:select sum(field1) as sumvalue from table1 ["FC
平均:select avg(field1) as avgvalue from table1 i={ :6K?^
最大:select max(field1) as maxvalue from table1 q:OSQ~U_
最小:select min(field1) as minvalue from table1 7D5;lM[_
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11、说明:几个高级查询运算词 hD OEJ
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A: UNION 运算符 /SLAg&
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。 e_Cns&
B: EXCEPT 运算符 HS1Gy/6'
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。 ` oBlv
C: INTERSECT 运算符 "S$4pj`<
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 x,kZ>^]&b
注:使用运算词的几个查询结果行必须是一致的。 Z#8O)GK
12、说明:使用外连接 YyI4T/0s_
A、left outer join: ZY%]F,Y
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ,,*i!%Adw
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4]\f}
B:right outer join: XhF7%KR
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 j\V9o9D
C:full outer join: lZpa)1.tiC
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 jY.iQBhjEB
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二、提升 EH;w
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) E_VLI'Hn?
法一:select * into b from a where 1<>1 .gmNE$d
法二:select top 0 * into b from a JN5<=x5r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _ZgIm3p0A
insert into b(a, b, c) select d,e,f from b; GWs[a$|
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) x50,4J%J'r
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 WdXi
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. C %l!"s^
4、说明:子查询(表名1:a 表名2:b) KH4
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) PA5_
5、说明:显示文章、提交人和最后回复时间 O0?.$f9 s
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b NL})_.Og
6、说明:外连接查询(表名1:a 表名2:b) 3U#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 \/8 I6a=
7、说明:在线视图查询(表名1:a ) ]6wo]nV[P
select * from (SELECT a,b,c FROM a) T where t.a > 1; *G{%]\s?
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 ?t LJe
select * from table1 where time between time1 and time2 XY(3!>/eQ[
select a,b,c, from table1 where a not between 数值1 and 数值2 5w:
9、说明:in 的使用方法 yGN@Hd:9
select * from table1 where a [not] in ('值1','值2','值4','值6') ^X$k<n A;
10、说明:两张关联表,删除主表中已经在副表中没有的信息 igNZe."V
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 2i+'?.P
11、说明:四表联查问题: &<</[h/B/F
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 ..... ~T<yp
12、说明:日程安排提前五分钟提醒 EC6)g;CO
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Lb# e
13、说明:一条sql 语句搞定数据库分页 #&+0hS
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 {Mt4QA5iZ
14、说明:前10条记录 ;g[C=yhK`C
select top 10 * form table1 where 范围 ?A|8J5EV
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.) rDNz<{evj
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) A?{ X5`y
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 _*b1]<
(select a from tableA ) except (select a from tableB) except (select a from tableC) g(d9=xq@k
17、说明:随机取出10条数据 :r^c_Ui
select top 10 * from tablename order by newid() =*Z=My}3~
18、说明:随机选择记录 WB S~e
select newid() >YPC&@9
19、说明:删除重复记录 PZn[Yb:
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) r81YL
20、说明:列出数据库里所有的表名 d/>owCwQ
select name from sysobjects where type='U' QN=a{
21、说明:列出表里的所有的 (;1FhIi&
select name from syscolumns where id=object_id('TableName') :[#g_*G@p
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。 #V4kT*2P)
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 U1?*vwfKZ
显示结果: ; z_ZZ(W
type vender pcs *2O4 *Q1
电脑 A 1 F.P4c:GD
电脑 A 1 4_3O?IY
光盘 B 2 /]=dPb%
光盘 A 2 t7 |uZHKK
手机 B 3 odxsF(Q0p
手机 C 3 ,#G>&
23、说明:初始化表table1 6< x0e;>
TRUNCATE TABLE table1 2UYtFWB9o
24、说明:选择从10到15的记录 F,0@z/8a
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >sAZT:&gv
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三、技巧 G{*m] 0Q
1、1=1,1=2的使用,在SQL语句组合时用的较多 bH}6N>Fp
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +^% y&8e
如: ns_5|*'
if @strWhere !='' ` aTkIo:ms
begin YxH"*)N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Kp")
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end H\ A!oB,sw
else 8>.l4:`
begin jg8j>"Vj>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 7Mxw0J
end _RG!lmJV
我们可以直接写成 a/!!Y@7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere VO ^[7Y
2、收缩数据库 ~YO-GX(
--重建索引 /60`"xH
DBCC REINDEX X+;F5b9z
DBCC INDEXDEFRAG xEBiBskd
--收缩数据和日志 6
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DBCC SHRINKDB @-dM'R6C
DBCC SHRINKFILE Q+/:5Z
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3、压缩数据库 \tFg10
dbcc shrinkdatabase(dbname) xao'L
4、转移数据库给新用户以已存在用户权限 \-kX-Tq
exec sp_change_users_login 'update_one','newname','oldname' 2XJn3wPi
go j&(2ze:=*$
5、检查备份集 :5X1Tr=A
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' YH33E~f
6、修复数据库 9tmYrhb$
ALTER DATABASE [dvbbs] SET SINGLE_USER eCB(!Y|
GO %=x|.e@J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Y%9S4be
GO uN bOtA
ALTER DATABASE [dvbbs] SET MULTI_USER @/}{Trmg/
GO ,)mqd2)+"
7、日志清除 R
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SET NOCOUNT ON =jvM$
DECLARE @LogicalFileName sysname, /sY(/ JE
@MaxMinutes INT, =T5vu~[J/e
@NewSize INT xz#;F ,`ZR
USE tablename -- 要操作的数据库名 #*uSYGdc
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 65bLkR{0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?Dro)fH1
@NewSize = 1 -- 你想设定的日志文件的大小(M) 5T,Doxo
-- Setup / initialize gwk$|aT@
DECLARE @OriginalSize int ia15r\4j)
SELECT @OriginalSize = size <{@?c
FROM sysfiles MdK!Y
WHERE name = @LogicalFileName .J' 8d"+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4?XX_=+F|
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + REnd#
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' w)-@?jN
FROM sysfiles 87%t=X
WHERE name = @LogicalFileName P9Hv){z
CREATE TABLE DummyTrans ^_b+o
(DummyColumn char (8000) not null) bF %#KSVw
DECLARE @Counter INT, rDkAeX0
@StartTime DATETIME, vlCjh! x
@TruncLog VARCHAR(255) h: :'s&|
SELECT @StartTime = GETDATE(), 24{!j[,q@
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Saa#Mj`M
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ]bO{001y,
EXEC (@TruncLog) !!&H'XEJV
-- Wrap the log if necessary. N#{d_v^H?d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 3#R~>c2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) e#Jx|Ej=
AND (@OriginalSize * 8 /1024) > @NewSize I@P[}XS
BEGIN -- Outer loop. ey<u
SELECT @Counter = 0 X0
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) R`ajll1
BEGIN -- update xB:,l'\G
INSERT DummyTrans VALUES ('Fill Log') r$=MBeT
DELETE DummyTrans ?RGL0`Lg
SELECT @Counter = @Counter + 1 flTK
END PETrMu<
EXEC (@TruncLog)
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END LNml["
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <4}zl'.
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + rb%P30qc4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !o~% F5|t
FROM sysfiles (:E_m|00;
WHERE name = @LogicalFileName (V@g?|LZ
DROP TABLE DummyTrans <uNBsYMuC
SET NOCOUNT OFF $K^"a
8、说明:更改某个表 !%J;dOcU
exec sp_changeobjectowner 'tablename','dbo' %@q52ZQ
9、存储更改全部表 %lz \w{
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch b!SGQv(^M
@OldOwner as NVARCHAR(128), Fh& `v0
@NewOwner as NVARCHAR(128) iaXNf
])?
AS K"Vv=
DECLARE @Name as NVARCHAR(128) kHd_q.
DECLARE @Owner as NVARCHAR(128) raY5 nc{
DECLARE @OwnerName as NVARCHAR(128) 4q[C'
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DECLARE curObject CURSOR FOR NuI9"I/
select 'Name' = name, mk_cub@
'Owner' = user_name(uid) {YWj`K
from sysobjects GdEkA
where user_name(uid)=@OldOwner qu BTRW9
order by name :s+AIo6
OPEN curObject ~\4l*$3(^
FETCH NEXT FROM curObject INTO @Name, @Owner Q6Y1Jr">X
WHILE(@@FETCH_STATUS=0) q7mqzMDk
BEGIN Xhtc0\0"(
if @Owner=@OldOwner SSycQ4[{o
begin ZT4._|2
set @OwnerName = @OldOwner + '.' + rtrim(@Name) soW.
exec sp_changeobjectowner @OwnerName, @NewOwner Z"'rc.>a
end J}EQ_FC"$
-- select @name,@NewOwner,@OldOwner WGKN>nV
FETCH NEXT FROM curObject INTO @Name, @Owner P482D)
END j(F%uUpN
close curObject 6@g2v^ %
deallocate curObject !1+L0,I6
GO o,9E~Q '`{
10、SQL SERVER中直接循环写入数据 6#vD>@H
declare @i int vmJ1-<G4*
set @i=1 SPOg'
while @i<30
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begin f}^}d"&F
insert into test (userid) values(@i) U`K5 DZ~
set @i=@i+1 ,=B
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end -'BJhi\Y]~
小记存储过程中经常用到的本周,本月,本年函数 NZ9=hI;iM
Dateadd(wk,datediff(wk,0,getdate()),-1) (`GO@
Dateadd(wk,datediff(wk,0,getdate()),6) mA(K`"Bfh
Dateadd(mm,datediff(mm,0,getdate()),0) H&E c*MT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) dm,7OQ
Dateadd(yy,datediff(yy,0,getdate()),0) LD: w
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) S0/@y'q3en
上面的SQL代码只是一个时间段 ]kbmbO?M
Dateadd(wk,datediff(wk,0,getdate()),-1) rmUTl
Dateadd(wk,datediff(wk,0,getdate()),6) Hq$AF
就是表示本周时间段. ;4 R1
下面的SQL的条件部分,就是查询时间段在本周范围内的: X3(:)zUL
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ()JM161
而在存储过程中 DF%\1C>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) * gr{{c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Z/sB72K1