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。 x_vaYUl)
I=)u:l c
r_f?H@v
一、基础 9""e*-;Mi
1、说明:创建数据库 _>8ZL)NQQ
CREATE DATABASE database-name 8(euWS
2、说明:删除数据库 >'^Tp7\
drop database dbname 1o. O]>
3、说明:备份sql server Quy&CV{@
--- 创建 备份数据的 device Pwn3/+"%K
USE master ao]Dm#HiO
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -lL(:drn
--- 开始 备份 =1noT)gCR
BACKUP DATABASE pubs TO testBack qcSlY&6+
4、说明:创建新表 VL5GX(
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )A}u)PH4O
根据已有的表创建新表: dBKL_'@@}
A:create table tab_new like tab_old (使用旧表创建新表) 60B6~@]P
B:create table tab_new as select col1,col2... from tab_old definition only N,9W18
@
5、说明:删除新表 ?8AchbK;N
drop table tabname Tji G!W8
6、说明:增加一个列 Nr?Z[6O|
Alter table tabname add column col type gJEm
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。 \a+.~_iL|
7、说明:添加主键: Alter table tabname add primary key(col) Y[l*>}:w
说明:删除主键: Alter table tabname drop primary key(col) }&+b\RE
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9?5'>WO
删除索引:drop index idxname
{Jf["Z
注:索引是不可更改的,想更改必须删除重新建。 `52+.*J+%
9、说明:创建视图:create view viewname as select statement =]k0*\PS
删除视图:drop view viewname ]W^F!p~eC
10、说明:几个简单的基本的sql语句 ?RyeZKf
选择:select * from table1 where 范围 OIpkXM
插入:insert into table1(field1,field2) values(value1,value2) $]v=2j
删除:delete from table1 where 范围 ]}t6V]`Q
更新:update table1 set field1=value1 where 范围 ^O#>LbM"x
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! }
+
]A?'&
排序:select * from table1 order by field1,field2 [desc] cR'l\iv+
总数:select count as totalcount from table1 N`3q54_$
求和:select sum(field1) as sumvalue from table1 (X=JT
平均:select avg(field1) as avgvalue from table1 >|{n";n&
最大:select max(field1) as maxvalue from table1 ,E8:!r)6
最小:select min(field1) as minvalue from table1 w; [ndZCY7
<'n'>@
e"7<&%
Oq
CD}::7$
11、说明:几个高级查询运算词 muh[wo
sIUhk7Cd8
hkS0ae
A: UNION 运算符 2/XrorV
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。 tu5g> qb
B: EXCEPT 运算符 'q3<R%^Q
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。 |2<y
C: INTERSECT 运算符 /g/]Q^
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。 J,iS<lV_
注:使用运算词的几个查询结果行必须是一致的。 p.wed%O.
12、说明:使用外连接 F9ytU>zh
A、left outer join: N>pTl$\4
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 O`?qnNmc;
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c tQR qQ
B:right outer join: n["G
ry
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 zR@4Z>6
C:full outer join: 4d x4hBd
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ?04jkq&
"SMRvi57T
4{PN9i
E
二、提升 .(J~:U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6Qc
*:(GE
法一:select * into b from a where 1<>1 #%9t-
法二:select top 0 * into b from a 'c7'iDM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) CMhl*dH
insert into b(a, b, c) select d,e,f from b; %I^schE*
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 7MbV|gM}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 h5)4Z^n
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. #]rfKHW9
4、说明:子查询(表名1:a 表名2:b) &0b\E73
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) EpW89X
5、说明:显示文章、提交人和最后回复时间 yac4\%ze
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b *P01 yW0
6、说明:外连接查询(表名1:a 表名2:b) K' ?`'7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /4I9Elr
7、说明:在线视图查询(表名1:a ) gB_gjn\
select * from (SELECT a,b,c FROM a) T where t.a > 1; >b7Yk)[%
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括
S4S}go*G[
select * from table1 where time between time1 and time2 SuR+Vv
select a,b,c, from table1 where a not between 数值1 and 数值2 ~0@uR
9、说明:in 的使用方法 :
uxJGx
select * from table1 where a [not] in ('值1','值2','值4','值6') <B
Vx%
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :Z[|B(U
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Y=?Tm,z4
11、说明:四表联查问题: NwcRH9};i
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... r9Vt}]$aG
12、说明:日程安排提前五分钟提醒 lyS`X
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Pk3b#$+E
13、说明:一条sql 语句搞定数据库分页 csFLBP
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 }~v&
14、说明:前10条记录 V.e30u5
select top 10 * form table1 where 范围 &s8vmUt
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) A I v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) >:bXw#w]
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 (j(hr'f
(select a from tableA ) except (select a from tableB) except (select a from tableC) /pC60y}O0
17、说明:随机取出10条数据 #[&9~za'"m
select top 10 * from tablename order by newid() R('\i/fy
18、说明:随机选择记录 ok1w4#%,
select newid() I.gF38Mx
19、说明:删除重复记录 k?}y@$[)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) sB*!Nf^y
20、说明:列出数据库里所有的表名 mKLWz1GZ
select name from sysobjects where type='U' rMoz+{1A
21、说明:列出表里的所有的 +3k.xP?QS
select name from syscolumns where id=object_id('TableName') E#E&z(G2
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。 $3S`A]xO
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type U]&/F{3
im
显示结果: 8{
+KNqz
type vender pcs X"V)oC
电脑 A 1 <Zo{D |hW
电脑 A 1 C{G;G@/7
光盘 B 2 6"9(ce
KX
光盘 A 2 E&ReQgBft
手机 B 3 !y862oKD
手机 C 3 eF(oHn,
23、说明:初始化表table1 vW0U~(XlN
TRUNCATE TABLE table1 yBCLS550
24、说明:选择从10到15的记录 +Mb}70^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc sVH
w\_F$
VFK]{!C_
U1D;O}z~
hT%
>)71
三、技巧 @ %o'
1、1=1,1=2的使用,在SQL语句组合时用的较多 JF'<""
"where 1=1" 是表示选择全部 "where 1=2"全部不选, DB0?H+8t
如: R1Fcd@DWD
if @strWhere !='' It]GlxMX
begin \'&,9lP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere FzF#V=9lP
end KuF>2KX~Y
else a{Y8hR
begin %"ehZd0r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5^{I}Q
end Y=/;7T
我们可以直接写成 $,o@&QT?AT
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere F5+!Gb En
2、收缩数据库 BnG{)\s
--重建索引 ~ymSsoD^
DBCC REINDEX O4!!*0(+91
DBCC INDEXDEFRAG +E+I.}sOB
--收缩数据和日志 W]D+[mpgK
DBCC SHRINKDB @vO~'Xxq!
DBCC SHRINKFILE \Hu?K\SWs
3、压缩数据库 ;,Os3
dbcc shrinkdatabase(dbname) P!!:p2fo
4、转移数据库给新用户以已存在用户权限 1i#U&
exec sp_change_users_login 'update_one','newname','oldname' lr[&*v?h
go R8|FqBs
5、检查备份集 ?{~. }Vn
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' `a8&7J(
6、修复数据库 XcKyrh;i
ALTER DATABASE [dvbbs] SET SINGLE_USER GXR7Ug}k
GO 6Z-[-0o+g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;(s.G-9S
GO b{,vZhP-
ALTER DATABASE [dvbbs] SET MULTI_USER 3V/f-l]X/
GO #B__-"cRv
7、日志清除 zc1~q
SET NOCOUNT ON (`d_DQ
DECLARE @LogicalFileName sysname, zeuSk|O
@MaxMinutes INT, 9$^v*!<z\
@NewSize INT ^3nB2G.ax
USE tablename -- 要操作的数据库名 G 'CYvV
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [ZETyM`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. KvEZbf3f
@NewSize = 1 -- 你想设定的日志文件的大小(M) [[Usrbf
-- Setup / initialize |RI77b:pX
DECLARE @OriginalSize int aT=V/Xh}d
SELECT @OriginalSize = size EU()Nnm2
FROM sysfiles xKoNo^FF
WHERE name = @LogicalFileName w*AXD!}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + w&}UgtEm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Q?Uk%t\hwc
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "HbrYYRb'
FROM sysfiles _1?Fyu&<5
WHERE name = @LogicalFileName BYs^?IfW
CREATE TABLE DummyTrans Xqas[:)7+
(DummyColumn char (8000) not null) V__n9L/t
DECLARE @Counter INT, JmVha!<qk
@StartTime DATETIME, 1;9 %L@
@TruncLog VARCHAR(255) G$
Ii
SELECT @StartTime = GETDATE(), #e;\Eap
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' LWP&Si*j
DBCC SHRINKFILE (@LogicalFileName, @NewSize) JOx""R8T5
EXEC (@TruncLog) @0rwvyE=+3
-- Wrap the log if necessary. !& xc.39
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired hH@pA:`s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^
P=CoLFa
AND (@OriginalSize * 8 /1024) > @NewSize ;?:X_C
BEGIN -- Outer loop. y8\4TjS1
SELECT @Counter = 0 >5-]Ur~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 0)3*E)g{
BEGIN -- update %GDs/9
INSERT DummyTrans VALUES ('Fill Log') x^]1m%
DELETE DummyTrans eVy\)dCsU
SELECT @Counter = @Counter + 1 4S#q06=Xe
END :n<<hR0d
EXEC (@TruncLog) dKTUW<C
END Nh|QYxOP
SELECT 'Final Size of ' + db_name() + ' LOG is ' + eEkbD"Q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Fu!sw]6xx
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' D*#r
V
P
FROM sysfiles kP}91kja
WHERE name = @LogicalFileName ni x1_Wo;
DROP TABLE DummyTrans awa$o
SET NOCOUNT OFF zos#B30
8、说明:更改某个表 ,b8q$R~\
exec sp_changeobjectowner 'tablename','dbo'
UBxQ4)%
9、存储更改全部表 ZX!u\O|w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch B%Spmx8
@OldOwner as NVARCHAR(128), y|@=j~}Zq
@NewOwner as NVARCHAR(128) y:8*!}fR
AS I|?Z.!I|
DECLARE @Name as NVARCHAR(128) .4wp
DECLARE @Owner as NVARCHAR(128) Ju7nvxC
DECLARE @OwnerName as NVARCHAR(128) o$DJL11E
DECLARE curObject CURSOR FOR y(RK|r
select 'Name' = name, u)fmXoQ
'Owner' = user_name(uid) ]%5DuE\M8\
from sysobjects Kr]`.@/.S
where user_name(uid)=@OldOwner Xpd^^
order by name 7)Rx-
OPEN curObject TBYRY)~f
FETCH NEXT FROM curObject INTO @Name, @Owner KwiTnP!Dca
WHILE(@@FETCH_STATUS=0) L_YVe(dT
BEGIN It@ak6u?
if @Owner=@OldOwner j@b4)t
begin 7=ZB?@bU~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8?r
,ylUj
exec sp_changeobjectowner @OwnerName, @NewOwner <99Xg_e
end AhARBgf<
-- select @name,@NewOwner,@OldOwner /IC7q?avQN
FETCH NEXT FROM curObject INTO @Name, @Owner vO2o/
END A8R}W=
close curObject [EJ[Gg0m
deallocate curObject n(b(H`1n
GO l*]*.?m/5
10、SQL SERVER中直接循环写入数据 cFoDR
declare @i int h*Y);mc$#
set @i=1 ( {H5k''
while @i<30 %Y` @>P'
begin zZ|Si
insert into test (userid) values(@i) j#b?P=|l
set @i=@i+1 q@p-)+D;
end !0~$u3[b
小记存储过程中经常用到的本周,本月,本年函数 tw]RH(g+#
Dateadd(wk,datediff(wk,0,getdate()),-1) por[p\M.
Dateadd(wk,datediff(wk,0,getdate()),6) oO|zRK1;/
Dateadd(mm,datediff(mm,0,getdate()),0)
P.RlozF5;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,iU ]zN//
Dateadd(yy,datediff(yy,0,getdate()),0) m[C-/f^u|
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5[M?O4mi
上面的SQL代码只是一个时间段 /)xG%J7H
Dateadd(wk,datediff(wk,0,getdate()),-1) z.:{
Dateadd(wk,datediff(wk,0,getdate()),6) 4XDR?KUM
就是表示本周时间段. :xfD>K
下面的SQL的条件部分,就是查询时间段在本周范围内的: H>[1DH#b
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $Tt@Xu
而在存储过程中 $L.0$-je4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Z
xLjh
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) dx@#6Fhy