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。 AkQ~k0i}b
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一、基础 FQ5U$x.[P
1、说明:创建数据库 wDe& 1(T^
CREATE DATABASE database-name A2jUmK.&
2、说明:删除数据库 f=K]XTw~
drop database dbname :&9s,l
3、说明:备份sql server ;@|n @ax
--- 创建 备份数据的 device 81
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USE master v,>Dbxn
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @t_=Yl2;
--- 开始 备份 Z}Ft:7
BACKUP DATABASE pubs TO testBack DN5 7p!z
4、说明:创建新表 A{D];pE`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Fy-t T]Q9
根据已有的表创建新表: ?2Py_gkf
A:create table tab_new like tab_old (使用旧表创建新表) wEvVL
B:create table tab_new as select col1,col2... from tab_old definition only P
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5、说明:删除新表 bB3powy9
drop table tabname UrEs4R1#
6、说明:增加一个列 :E )>\&
Alter table tabname add column col type
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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。 9m~p0 ILh
7、说明:添加主键: Alter table tabname add primary key(col) *wB1,U{
说明:删除主键: Alter table tabname drop primary key(col) 5taT5?n2
8、说明:创建索引:create [unique] index idxname on tabname(col....) e h?zNu2=
删除索引:drop index idxname P?of<i2E
注:索引是不可更改的,想更改必须删除重新建。 ExL0?FemWV
9、说明:创建视图:create view viewname as select statement L>4"(
删除视图:drop view viewname -4{<=y?"a
10、说明:几个简单的基本的sql语句 LuvY<~u
选择:select * from table1 where 范围 lp%pbx43s
插入:insert into table1(field1,field2) values(value1,value2) ~%kkeh\j
删除:delete from table1 where 范围 P:MT*ra*,
更新:update table1 set field1=value1 where 范围 t=W}SH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! mSl.mi(JiZ
排序:select * from table1 order by field1,field2 [desc] K^<BW(s
总数:select count as totalcount from table1 +}os&[S
求和:select sum(field1) as sumvalue from table1 UhQj
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平均:select avg(field1) as avgvalue from table1 0[?Xxk}s0
最大:select max(field1) as maxvalue from table1 ?QdWrE_
最小:select min(field1) as minvalue from table1 :(*V?WI
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11、说明:几个高级查询运算词 dk4CpN
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A: UNION 运算符 dn$!&
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。 w-L=LWL\
B: EXCEPT 运算符 PmEsN&YP]
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。 3kp+<$
C: INTERSECT 运算符 6)
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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。 XrGglBIV
注:使用运算词的几个查询结果行必须是一致的。 V#gK$uv
12、说明:使用外连接 gu.}M:u
A、left outer join: eiaFaYe\
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 XW)lDiJl
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o~y;j75{.*
B:right outer join: c2 C8g1n
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ['tY4$L(
C:full outer join: R=2FNP
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。 ,G?WAOy,
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二、提升 9W1YW9rL
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) yg=q;Z>[~
法一:select * into b from a where 1<>1 ~[nSXnPO
法二:select top 0 * into b from a H;k~oIsk
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3<f}nfB%r?
insert into b(a, b, c) select d,e,f from b; 2E)-M9ds
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) ,Np0wg0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k|PN0&J
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. M; tqp8
4、说明:子查询(表名1:a 表名2:b) :vQrOn18p
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) :zke %Yx
5、说明:显示文章、提交人和最后回复时间 5 ,B_u%bb
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CXx*_@}MU
6、说明:外连接查询(表名1:a 表名2:b) \\H}`0m:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '"/=f\)u
7、说明:在线视图查询(表名1:a ) <7Or{:Sc90
select * from (SELECT a,b,c FROM a) T where t.a > 1; cO+qs[
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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 k&vz7Q`T
select * from table1 where time between time1 and time2 u5b|#&-mX
select a,b,c, from table1 where a not between 数值1 and 数值2 BLf>_bUk
9、说明:in 的使用方法 DGn;m\B
select * from table1 where a [not] in ('值1','值2','值4','值6') X Dm[Gc>(~
10、说明:两张关联表,删除主表中已经在副表中没有的信息 pG^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) m6\E$;`
11、说明:四表联查问题: ~#[yJNYQ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... .K2qXw"S#
12、说明:日程安排提前五分钟提醒 qUW!
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;LPfXpR
13、说明:一条sql 语句搞定数据库分页 m{cGK`/\
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 _Gi4A
14、说明:前10条记录 oC: {aK6\
select top 10 * form table1 where 范围 G+"t/?/
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) /1V xc 6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5o'FS{6U
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 U!?_W=?
(select a from tableA ) except (select a from tableB) except (select a from tableC) ;oKZ!ND
17、说明:随机取出10条数据 {14fA)`%
select top 10 * from tablename order by newid() qJa H,
18、说明:随机选择记录 {
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select newid() r|fL&dtr
19、说明:删除重复记录 Zd}9O jz5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) m_?~OL S
20、说明:列出数据库里所有的表名 y@: h4u"3
select name from sysobjects where type='U' 0oZ=
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21、说明:列出表里的所有的 .* ?wF
select name from syscolumns where id=object_id('TableName') I7vz+>Jr
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ):6 8%,
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type M2>Vj/
显示结果: Ml{Z
type vender pcs Fg5kX
电脑 A 1 0$)>D==
电脑 A 1 6azGhxh
光盘 B 2 {JO
光盘 A 2 7cT~oV !G_
手机 B 3 p{Yv3dNl
手机 C 3 F^t DL:
23、说明:初始化表table1 r?lf($D*
TRUNCATE TABLE table1 "fCu=@i
24、说明:选择从10到15的记录 p;59?
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc y^,1a[U.
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三、技巧 7{)G_?Q&
1、1=1,1=2的使用,在SQL语句组合时用的较多 jrlVvzZ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~ Ei $nV
如: RK'\C\gMDu
if @strWhere !='' GmeQ`;9,
begin hz;G$cuEE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere h-#6av:
end nwB_8mN|
else QT<
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begin :0j?oY~e
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,.83m%i
end LqoB 10Kc\
我们可以直接写成 "3)C'WlEy/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +,TRfP
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2、收缩数据库 @uqd.Q
--重建索引 U0
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DBCC REINDEX (cAIvgI
DBCC INDEXDEFRAG h5{'Q$Erl
--收缩数据和日志 1MP~dRZ$
DBCC SHRINKDB [LjT*bi
DBCC SHRINKFILE L%*!`TN
3、压缩数据库 hYT0l$Ng
dbcc shrinkdatabase(dbname) szZr4y<8|1
4、转移数据库给新用户以已存在用户权限 e#L8X
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exec sp_change_users_login 'update_one','newname','oldname' SIF/-{i(X
go [fya)}
5、检查备份集 @Q
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' yYIf5S`V]
6、修复数据库 zU kgG61
ALTER DATABASE [dvbbs] SET SINGLE_USER dUeN*Nq&(,
GO )BZ.Sv
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK KQaxvU)L
GO @w#-aGJO
ALTER DATABASE [dvbbs] SET MULTI_USER q1$N>;&
GO p*R;hU
7、日志清除 Cx(>RXVoJ,
SET NOCOUNT ON Fh?gNSWq6
DECLARE @LogicalFileName sysname, ??-[eB.
@MaxMinutes INT, W+aP}rZm:
@NewSize INT 67JA=,EE
USE tablename -- 要操作的数据库名 (^8Y|:Tz
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~ drS} V
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zH?!
@NewSize = 1 -- 你想设定的日志文件的大小(M) u<7/0;D#+
-- Setup / initialize }l(&}#dY
DECLARE @OriginalSize int Gv!2f
SELECT @OriginalSize = size ~NrG`
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FROM sysfiles ~9a<0Mc?
WHERE name = @LogicalFileName j\[dx^\=
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )0.kv2o.
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }>pknc?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7{e
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FROM sysfiles r_)' Ps
WHERE name = @LogicalFileName P%V'4p c
CREATE TABLE DummyTrans GfxZ'VIn
(DummyColumn char (8000) not null) fa
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DECLARE @Counter INT, :KSV4>X[%a
@StartTime DATETIME, rKe2/4>0X
@TruncLog VARCHAR(255) fy>{QC\
SELECT @StartTime = GETDATE(), aD<A.Lhy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' y|C(X
DBCC SHRINKFILE (@LogicalFileName, @NewSize) qTRsZz@
EXEC (@TruncLog) ,8S/t+H
-- Wrap the log if necessary. -/wtI
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tVYF{3BhA
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :;RMo2Tl
AND (@OriginalSize * 8 /1024) > @NewSize YFLZ %(
BEGIN -- Outer loop. s[RAHU
SELECT @Counter = 0 dc+>m,3$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2.`\
BEGIN -- update Fd%#78UEo}
INSERT DummyTrans VALUES ('Fill Log') #5Q pu
DELETE DummyTrans c?(4t67|
SELECT @Counter = @Counter + 1 vONasD9At
END p,EQ#Ik
EXEC (@TruncLog) 9%o32eo,3
END +xh`Q=A
SELECT 'Final Size of ' + db_name() + ' LOG is ' + L4@K~8j7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + B?eCe}*f;B
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' zq3\}9
FROM sysfiles !j8FIY'[
WHERE name = @LogicalFileName wjU9ZGM
DROP TABLE DummyTrans GL>O4S<`
SET NOCOUNT OFF afCW(zHp
8、说明:更改某个表 yJ[0WY8<kC
exec sp_changeobjectowner 'tablename','dbo' QGMV}y
9、存储更改全部表 <O(4TO
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |%BOZT
@OldOwner as NVARCHAR(128), 5c@,bIl *
@NewOwner as NVARCHAR(128) >2Y=*K,:
AS 3H'sHuK"X
DECLARE @Name as NVARCHAR(128) KaLzg5is
DECLARE @Owner as NVARCHAR(128) Z\(q@3 C
DECLARE @OwnerName as NVARCHAR(128) -vAC"8)S
DECLARE curObject CURSOR FOR AmUr.ofu
select 'Name' = name, SpIv#?
'Owner' = user_name(uid) [$ubNk;!z
from sysobjects z{%<<pZ
where user_name(uid)=@OldOwner @f_Lp%K
order by name I
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OPEN curObject ")1:F>
FETCH NEXT FROM curObject INTO @Name, @Owner DHg:8%3x
WHILE(@@FETCH_STATUS=0) WJ]T\DI
BEGIN *[Imn\hu
if @Owner=@OldOwner `Y0%cXi3
begin R)?*N@.s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,5P0S0*{
exec sp_changeobjectowner @OwnerName, @NewOwner [CTnXb
end '9%\;
-- select @name,@NewOwner,@OldOwner B5,N7z34F
FETCH NEXT FROM curObject INTO @Name, @Owner ^L,K& Jd
END ^7`BP%6
close curObject ]"pVj6O
deallocate curObject }g@v`5
GO dUD[e,?
10、SQL SERVER中直接循环写入数据 WSPI|#Xr%
declare @i int s2a{>II6
set @i=1 {Ea
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while @i<30 xf'V{9*
begin bS{bkE>
insert into test (userid) values(@i) "6("9"
set @i=@i+1 ;_XFo&@
end nd`1m[7MNu
小记存储过程中经常用到的本周,本月,本年函数 PioZIb/{
Dateadd(wk,datediff(wk,0,getdate()),-1) ]HbY
Dateadd(wk,datediff(wk,0,getdate()),6) av(6wht8
Dateadd(mm,datediff(mm,0,getdate()),0) 3RUy,s
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) e_^26^{q
Dateadd(yy,datediff(yy,0,getdate()),0) \Zb;'eDv
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !@5 9)
上面的SQL代码只是一个时间段 x
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Dateadd(wk,datediff(wk,0,getdate()),-1) iR HQ:Y!
Dateadd(wk,datediff(wk,0,getdate()),6) b;L\EB
就是表示本周时间段. ~kV/!=
下面的SQL的条件部分,就是查询时间段在本周范围内的: H[T?\Lq
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d.aS{;pse
而在存储过程中 \wmN
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 0RzEY!9g+
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) PgAf\.48a