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。 ^>y|{;`
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一、基础 Ou|kb61zg
1、说明:创建数据库 uPb. uG
CREATE DATABASE database-name r;"Qu
2、说明:删除数据库 GCxmqoQ
drop database dbname }AS3]Lub@
3、说明:备份sql server 8(!?y[
--- 创建 备份数据的 device h~Z:YY)4
USE master ^jk-GRD*
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rFW,x_*_vP
--- 开始 备份 Ma ]*Pled
BACKUP DATABASE pubs TO testBack FJsM3|{2=d
4、说明:创建新表 UQBc$`v
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {@ tO9pc`8
根据已有的表创建新表: t+Qx-sW
A:create table tab_new like tab_old (使用旧表创建新表) qt.=
B:create table tab_new as select col1,col2... from tab_old definition only J(,{ -d-E
5、说明:删除新表 a0`(*#P
drop table tabname "~08<+
6、说明:增加一个列 c$;Cpt@-j
Alter table tabname add column col type T7(U6yN
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。 jGDuKb@:
7、说明:添加主键: Alter table tabname add primary key(col) PJ)d5D%T
说明:删除主键: Alter table tabname drop primary key(col) q9nQ/]rkHF
8、说明:创建索引:create [unique] index idxname on tabname(col....) MX|@x~9W
删除索引:drop index idxname _u#r;h[
注:索引是不可更改的,想更改必须删除重新建。 VexQ ]
9、说明:创建视图:create view viewname as select statement (%4O\s#l
删除视图:drop view viewname -]:1zU
10、说明:几个简单的基本的sql语句 r
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选择:select * from table1 where 范围 ]OC?g2&6
插入:insert into table1(field1,field2) values(value1,value2) E/C3t2@-
删除:delete from table1 where 范围 \"+}-!wr
更新:update table1 set field1=value1 where 范围 8?hj}}H
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YG#{/;^nm)
排序:select * from table1 order by field1,field2 [desc] Mw6
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总数:select count as totalcount from table1 M1K[6V!
求和:select sum(field1) as sumvalue from table1 =BeJ.8$@VC
平均:select avg(field1) as avgvalue from table1 4B-+DH>{6
最大:select max(field1) as maxvalue from table1 Fw%S%*B8g
最小:select min(field1) as minvalue from table1 CmtDfE
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11、说明:几个高级查询运算词 u/`
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A: UNION 运算符 D\z`+TyJ
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 p<Vj<6.=?
B: EXCEPT 运算符 y6>fK@K~
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ~@D{&7@
C: INTERSECT 运算符 #ahe@|E'Y
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 z+j3j2
注:使用运算词的几个查询结果行必须是一致的。 7C~g?1
12、说明:使用外连接 4` :Eiik&p
A、left outer join: #D%l;Ae
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 n7bML?f'
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "]yfx@)_
B:right outer join: IG4`f~k^
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 wkD"EuW(
C:full outer join: I:] Pd
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 -g4 {:!*D
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二、提升 O?Qi
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) B1J2m^
法一:select * into b from a where 1<>1 }`_x%]EJ
法二:select top 0 * into b from a nO8e'&|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >NtJ)N*
insert into b(a, b, c) select d,e,f from b; T{lK$j
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) q]gF[&QZ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 vgKdhN2kI
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >2#F5c67
4、说明:子查询(表名1:a 表名2:b) v<gve<]
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) BBj>ML\X
5、说明:显示文章、提交人和最后回复时间 3Sn#
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Q'Y7PG9m~
6、说明:外连接查询(表名1:a 表名2:b) DhiIKd9W
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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7、说明:在线视图查询(表名1:a ) (6i.>%|_
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2Gn26L5
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 @5cY5e*i{
select * from table1 where time between time1 and time2 fh9w5hT={
select a,b,c, from table1 where a not between 数值1 and 数值2 ;sY n=r
9、说明:in 的使用方法 4R9y~~+
select * from table1 where a [not] in ('值1','值2','值4','值6') +<sv/gEt
10、说明:两张关联表,删除主表中已经在副表中没有的信息 cTdX'5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) q) y<\cEO
11、说明:四表联查问题: e^-CxHwA-
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 ..... ~L9I@(/S
12、说明:日程安排提前五分钟提醒 LbnW(wr6:(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Gg{M
13、说明:一条sql 语句搞定数据库分页 OsgjSJrf
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 "E7YCZQR
14、说明:前10条记录 A7zL\U4
select top 10 * form table1 where 范围 nZ#0L`@"Y
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`s;oc
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) JQA]O/|N
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 P u,JR
(select a from tableA ) except (select a from tableB) except (select a from tableC) +?GsIp@>jh
17、说明:随机取出10条数据 rpv<'$6
select top 10 * from tablename order by newid() N"zm
18、说明:随机选择记录 \mNN ) K@
select newid() &>vfm9
19、说明:删除重复记录 t:tIzFNv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \T^ptj(0
20、说明:列出数据库里所有的表名 vFi+ExBU
select name from sysobjects where type='U' fD2)/5j1
21、说明:列出表里的所有的 T!t9`I0Zz
select name from syscolumns where id=object_id('TableName') '~AR|8q?
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。 tIo
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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 ^8
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显示结果: yjIA`5^
type vender pcs kB_T9$0e#
电脑 A 1 =$\9t $A
电脑 A 1 |6b&khAM
光盘 B 2 Ko %e#q-
光盘 A 2 S i-Q'*Y=
手机 B 3 4.q^r]m*
手机 C 3 *+j r? |
23、说明:初始化表table1 MD[;Ha
TRUNCATE TABLE table1 )^j62uv
24、说明:选择从10到15的记录 >ui;B$=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4ms"mIt
Tvd: P^C
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三、技巧 G)&S%R!i\N
1、1=1,1=2的使用,在SQL语句组合时用的较多 2X 0<-Y#'
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ";
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如: F??gVa aj
if @strWhere !='' 9rgvwko
begin ?~tx@k$;Es
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere f<3lxu
end af}JS2=$
else qzii[Mf
begin 8T3Nz8Q7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
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end O@`KGZEPY
我们可以直接写成 :dwP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4z,/0
2、收缩数据库 h.5KzC
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--重建索引 {Hzj(c~S?
DBCC REINDEX YGOhUT |
DBCC INDEXDEFRAG ;.3
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--收缩数据和日志 3shd0q<
DBCC SHRINKDB P}"uC`036
DBCC SHRINKFILE kp^q}iS
3、压缩数据库 7
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dbcc shrinkdatabase(dbname) &M6Zsmo
4、转移数据库给新用户以已存在用户权限 !>EK
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exec sp_change_users_login 'update_one','newname','oldname' m`Pk )c0
go
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5、检查备份集 .a 9f)^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' W 'R^GIHs
6、修复数据库 LU+}iA)
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO pg{cZ1/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NF'<8{~
GO %\Mc6
ALTER DATABASE [dvbbs] SET MULTI_USER =kBN&v_(!
GO W:O p\
7、日志清除 UD ;UdehC
SET NOCOUNT ON +IG=|X
DECLARE @LogicalFileName sysname, "pc
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@MaxMinutes INT, 'CCAuN>J
@NewSize INT [I}xR(a@n
USE tablename -- 要操作的数据库名 ^m -w@0^z
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 'Ej+Jczzpp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >O~
@NewSize = 1 -- 你想设定的日志文件的大小(M) lg*?w/JX+
-- Setup / initialize Hd_,`W@
DECLARE @OriginalSize int 0e(4+:0
SELECT @OriginalSize = size t)4]2z)$
FROM sysfiles =A(Az
WHERE name = @LogicalFileName XzPUll;ZU
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {2U3
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )oy+-1dE
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' y-mjfW`n
FROM sysfiles >{>X.I~
WHERE name = @LogicalFileName SZ~lCdWad
CREATE TABLE DummyTrans 3zMaHh)mj
(DummyColumn char (8000) not null) )C0d*T0i
DECLARE @Counter INT, J>1%*Tz
@StartTime DATETIME, C@u}tH
)
@TruncLog VARCHAR(255) Op:$7hv
SELECT @StartTime = GETDATE(), Bv#?.0Ez;
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "%#CMCE|f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 5E
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EXEC (@TruncLog) &.P G2f*
-- Wrap the log if necessary. RM>A9nv$\
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired vK$wc~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aev(CY,z
AND (@OriginalSize * 8 /1024) > @NewSize e <+b?@}=B
BEGIN -- Outer loop. -?NAA]P5c@
SELECT @Counter = 0 \s7/`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cJzkA^T9
BEGIN -- update |nBZ :$D
INSERT DummyTrans VALUES ('Fill Log') '3xK1Am
DELETE DummyTrans 3ej[
SELECT @Counter = @Counter + 1 ^#U[v7y
END se*k56,
EXEC (@TruncLog) v1=N?8Hz1
END W=Mdh}u_I
SELECT 'Final Size of ' + db_name() + ' LOG is ' + bZpx61h|
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |\W~+}'g~
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,JfP$HJ
FROM sysfiles {+V ]@sz
WHERE name = @LogicalFileName -FW^fGS+
DROP TABLE DummyTrans ~/rKKc
SET NOCOUNT OFF nK#%Od{GF
8、说明:更改某个表 c[Z#q*Q
exec sp_changeobjectowner 'tablename','dbo' G|TnvZ KX
9、存储更改全部表 JH*fxG
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch o $'K}U
@OldOwner as NVARCHAR(128), 0S$TLbx
@NewOwner as NVARCHAR(128) ?RS4oJz,5g
AS eo^C[#
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DECLARE @Name as NVARCHAR(128) wV\G$|Y
DECLARE @Owner as NVARCHAR(128) #"fn;
DECLARE @OwnerName as NVARCHAR(128) Gh352
DECLARE curObject CURSOR FOR 3gtKD9RL:
select 'Name' = name, -B #K}xL|x
'Owner' = user_name(uid) "^wIixOH5
from sysobjects ;7*T6~tv
where user_name(uid)=@OldOwner ??lsv(v-
order by name t :~,7
OPEN curObject l[C_vUg
FETCH NEXT FROM curObject INTO @Name, @Owner 8+H 0
WHILE(@@FETCH_STATUS=0) =]1cVnPI
BEGIN H3( @Q^9
if @Owner=@OldOwner &joP-!"
begin j1=su~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) m[Mw2 F
exec sp_changeobjectowner @OwnerName, @NewOwner G!lF5;Ad`
end 9+ |W;
-- select @name,@NewOwner,@OldOwner
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FETCH NEXT FROM curObject INTO @Name, @Owner I=
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END Y(gai?
close curObject |XV`A)=f
deallocate curObject N?O^"
GO ]GD&EQ
10、SQL SERVER中直接循环写入数据 ~i!I6d~
declare @i int }$LnjwM;,
set @i=1 dVZ~n4
while @i<30 KyBtt47\
begin Q:Ma3El\
insert into test (userid) values(@i) tJmy}.t1
set @i=@i+1 NMUF)ksjN
end [3x},KM
小记存储过程中经常用到的本周,本月,本年函数 i*@ZIw
Dateadd(wk,datediff(wk,0,getdate()),-1) [I/ZzDMX
Dateadd(wk,datediff(wk,0,getdate()),6) <C451+95
Dateadd(mm,datediff(mm,0,getdate()),0) PcjeuJZ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) `U&'71B^
Dateadd(yy,datediff(yy,0,getdate()),0) 2#N?WlYw<S
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) &MPlSIg
上面的SQL代码只是一个时间段 E<7$!P=z`
Dateadd(wk,datediff(wk,0,getdate()),-1) w|ahb
Dateadd(wk,datediff(wk,0,getdate()),6) !M(SEIc4A
就是表示本周时间段. *$Zy|&[Z
下面的SQL的条件部分,就是查询时间段在本周范围内的: +O^} t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) u?F.%j-
而在存储过程中 Rtlc&Q.b
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) VP<LY/'f
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) QL*RzFAD3