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。 V>`9ey!U
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一、基础 \TYVAt]
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1、说明:创建数据库 _DAqL@5n
CREATE DATABASE database-name &*bpEdkZ
2、说明:删除数据库 v_WF.sb~
drop database dbname 8H1&=)M=
3、说明:备份sql server Q eN7~ J
--- 创建 备份数据的 device rp^:{6O
USE master re,}}'
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @+1AYVz(k
--- 开始 备份 B`gH({U
BACKUP DATABASE pubs TO testBack I2krxLPd
4、说明:创建新表 0dQ\Y]b
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z?d][zGw
根据已有的表创建新表: c[T@lz(!
A:create table tab_new like tab_old (使用旧表创建新表) cltx(C>
B:create table tab_new as select col1,col2... from tab_old definition only qA[cF$CIl)
5、说明:删除新表 EG|_YW7
drop table tabname Yg}b%u,Q
6、说明:增加一个列 x0%yz+i{:
Alter table tabname add column col type $d,/(*Y#-
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 pFV~1W:
7、说明:添加主键: Alter table tabname add primary key(col) uH(M@7"6_!
说明:删除主键: Alter table tabname drop primary key(col) |Qb@.
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9Fw NX
删除索引:drop index idxname [:}"MdU'
注:索引是不可更改的,想更改必须删除重新建。 UkXa mGoy3
9、说明:创建视图:create view viewname as select statement e+<|
删除视图:drop view viewname ktRGl>J
10、说明:几个简单的基本的sql语句 *yY\d.6(
选择:select * from table1 where 范围 GZHJ4|DK
插入:insert into table1(field1,field2) values(value1,value2) u%6b|M@P
删除:delete from table1 where 范围 LM 1Vsh<
更新:update table1 set field1=value1 where 范围 .;S1HOHz4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! d^v.tYM$N
排序:select * from table1 order by field1,field2 [desc] k2.k}?w!JO
总数:select count as totalcount from table1 p$ETAvD
求和:select sum(field1) as sumvalue from table1 j/F('r~L
平均:select avg(field1) as avgvalue from table1 kem(U{m
最大:select max(field1) as maxvalue from table1 +md"X@k5*
最小:select min(field1) as minvalue from table1 <:&{ c-f/
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11、说明:几个高级查询运算词 ,b5vnW\
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A: UNION 运算符 $pt~?ZZ3-
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。 mB6%. "
B: EXCEPT 运算符 GctV
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。 OEX\]!3_Fm
C: INTERSECT 运算符 us8HXvvp{
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。 d{7)_Sbky
注:使用运算词的几个查询结果行必须是一致的。 r:Q=6j,
12、说明:使用外连接 i) Q
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A、left outer join: US"UkY-\
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。 "!fwIEG
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 HuKOb4g
B:right outer join: 3lEP:Jp
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。 .JJ50p
C:full outer join: f! )yE`4-
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。 pSEaE9AX%
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二、提升 9qB4\ONXZ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ):nC%0V
法一:select * into b from a where 1<>1 #/8
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法二:select top 0 * into b from a 1_]%,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) V]"pM]>3X
insert into b(a, b, c) select d,e,f from b; ,7DyTeMpN
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) WS?Y8~+{5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 XW\
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +(z[8BJl
4、说明:子查询(表名1:a 表名2:b) "DH>4Q]
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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) U!K#g_}
5、说明:显示文章、提交人和最后回复时间 QUfF>,[sv
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b W7@Vma`
6、说明:外连接查询(表名1:a 表名2:b) %`\Qtsape
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #JY>
7、说明:在线视图查询(表名1:a ) "3|OB, <;:
select * from (SELECT a,b,c FROM a) T where t.a > 1; -j:yE Z4Oy
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 GU 9p'E
select * from table1 where time between time1 and time2 .2_xTt
select a,b,c, from table1 where a not between 数值1 and 数值2 m(EVC}Y
9、说明:in 的使用方法 :S7[<SwL
select * from table1 where a [not] in ('值1','值2','值4','值6') 57]La^#
10、说明:两张关联表,删除主表中已经在副表中没有的信息 X?JtEQ~>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) p,uM)LD
11、说明:四表联查问题: Q`4Ia<5B
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 ..... y@7CY-1
12、说明:日程安排提前五分钟提醒 B[
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Bn=YGEvz
13、说明:一条sql 语句搞定数据库分页 ?'"BX
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 .3@Pz]\M#>
14、说明:前10条记录 4d}n0b\d
select top 10 * form table1 where 范围 '<*%<J{(
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.) }w2Et
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %K06owV(S)
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 +Jn\`4/J:
(select a from tableA ) except (select a from tableB) except (select a from tableC) 0ia-D`^me
17、说明:随机取出10条数据 v6E5#pse8
select top 10 * from tablename order by newid() g:U
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18、说明:随机选择记录 yS[HYq
select newid() tK'9%yA\
19、说明:删除重复记录 qSD3]Dv"
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) B<$6Dj%L
20、说明:列出数据库里所有的表名 -%K}~4J
select name from sysobjects where type='U' &%k_BdlkQ
21、说明:列出表里的所有的 St>
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select name from syscolumns where id=object_id('TableName') Goy[P2m
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 +^J;ic
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type '"ze Im~
显示结果: 5B8fz;l= B
type vender pcs jqTK7b
电脑 A 1 ">S1,rhgS
电脑 A 1 `krVfE;_O
光盘 B 2 8YgRJQZ!
光盘 A 2 &Fjyi"8(r
手机 B 3 : t75iB=
手机 C 3 aD6!x3c/
23、说明:初始化表table1 A{T>Aac
TRUNCATE TABLE table1 E8<,j})*
24、说明:选择从10到15的记录 H`Zg-j`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Bsd~_y}8
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三、技巧 *YX:e@Fm.a
1、1=1,1=2的使用,在SQL语句组合时用的较多 *A")A.R
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 9;`hJ!r
如: XaoVv2=G~
if @strWhere !='' 8,VEuBZ
begin /+. m.TF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere O`N,aYo
end EaH/Gg3
else :!fY;c?
begin 1]A\@(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "d
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end |<y1<O>F
我们可以直接写成 [(.lfa P
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere f'`y-]"V5)
2、收缩数据库 Mpk7$=hjc
--重建索引 fZJM'+J@A
DBCC REINDEX 77 Z:!J|
DBCC INDEXDEFRAG #T`1Z"h<
--收缩数据和日志 _G/uDP%
DBCC SHRINKDB +@7c:CAy(
DBCC SHRINKFILE B)0;gWK
3、压缩数据库 +>c%I&h}`
dbcc shrinkdatabase(dbname) +#A~O4%t
4、转移数据库给新用户以已存在用户权限 Q7UQwAN'
exec sp_change_users_login 'update_one','newname','oldname' 3hzz*9/n
go L}A2$@
5、检查备份集 nvc(<Ovw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ywcgt|
6、修复数据库 <A`SC;k\u
ALTER DATABASE [dvbbs] SET SINGLE_USER km`";gUp>
GO Pi,86?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ^%Ln@!P
GO ~(`MP<
ALTER DATABASE [dvbbs] SET MULTI_USER F<dhG>E9
GO O@:R\MwFOZ
7、日志清除 )]E?~ $,
SET NOCOUNT ON rg]z
DECLARE @LogicalFileName sysname, !.4q{YWcYk
@MaxMinutes INT, J @IKXhb7_
@NewSize INT *xKy^f
USE tablename -- 要操作的数据库名 R+/kx#^
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 V{\1qg{
@MaxMinutes = 10, -- Limit on time allowed to wrap log. T$;BZ=_
@NewSize = 1 -- 你想设定的日志文件的大小(M) M~Er6Zg
-- Setup / initialize _=cuOo"!
DECLARE @OriginalSize int 55,2eg#{O
SELECT @OriginalSize = size %/!f^PIwX
FROM sysfiles !RjC0,
WHERE name = @LogicalFileName ,Hp7`I>/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + r CUs
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8k.#4}fP
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "tDB[?
FROM sysfiles r $ YEq5
WHERE name = @LogicalFileName )2u_[Jc=
CREATE TABLE DummyTrans UjyrmQf
(DummyColumn char (8000) not null) 9PaV*S(\TR
DECLARE @Counter INT, (S6>^:;=~
@StartTime DATETIME, ]IDhE{
@TruncLog VARCHAR(255) V~Jt
SELECT @StartTime = GETDATE(), Tq6\oIBkV
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' e#WASHZN
DBCC SHRINKFILE (@LogicalFileName, @NewSize) OL@$RTh
EXEC (@TruncLog) {"rL3Lk
-- Wrap the log if necessary. [8 23w.{]#
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired )U8=-_m
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ZK<c(,oZ^
AND (@OriginalSize * 8 /1024) > @NewSize 5 (q4o`
BEGIN -- Outer loop. "=$uv
SELECT @Counter = 0 zW[HGI6w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) VmXXj6l&
BEGIN -- update >]Dn,*R
INSERT DummyTrans VALUES ('Fill Log') BXytAz3
DELETE DummyTrans /NuO>kQa
SELECT @Counter = @Counter + 1 k?
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END 6.|[;>Km
EXEC (@TruncLog) zOy_qozk
END "K;""]#wg0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + '=Acg"aT
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + tQTjqy{K
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #;;A~d:V
FROM sysfiles PMQlJ&
WHERE name = @LogicalFileName nY?&k$n
DROP TABLE DummyTrans w(*},
SET NOCOUNT OFF T]\'D&P~D
8、说明:更改某个表 YjPj#57+
exec sp_changeobjectowner 'tablename','dbo' ]L3MIaO2T
9、存储更改全部表 {Z>Mnw"R
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch \#C]|\
@OldOwner as NVARCHAR(128), i7&ay\+@
@NewOwner as NVARCHAR(128) DJ1!Xuu
AS /7ykmW
DECLARE @Name as NVARCHAR(128) z.tN<P 7
DECLARE @Owner as NVARCHAR(128) ke2M&TV
DECLARE @OwnerName as NVARCHAR(128) QQ %W3D@
DECLARE curObject CURSOR FOR B f.- 5
select 'Name' = name, \J-D@b;
'Owner' = user_name(uid) jFI`CA6P
from sysobjects D23 c/8K
where user_name(uid)=@OldOwner g?@fHFct
order by name wb39s^n
OPEN curObject @z=L\e{
FETCH NEXT FROM curObject INTO @Name, @Owner QM7BFS;
WHILE(@@FETCH_STATUS=0) hK %FpGYA
BEGIN tNYuuC%N
if @Owner=@OldOwner B!4~A{
begin L} K8cB
set @OwnerName = @OldOwner + '.' + rtrim(@Name) sdN1BV2
exec sp_changeobjectowner @OwnerName, @NewOwner AH:0h X6+
end ,=: -&~?
-- select @name,@NewOwner,@OldOwner HY(XI u
FETCH NEXT FROM curObject INTO @Name, @Owner eEYzA
END Fnd_\`9{
close curObject 4MCj*ok<
deallocate curObject 0="wxB
GO {??bJRT
10、SQL SERVER中直接循环写入数据 ^3QJv{)Q
declare @i int {9cjitl
set @i=1 J"XZnb)E=
while @i<30 k/)h @K8@
begin N_l_^yD
insert into test (userid) values(@i) 5!Ovd
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set @i=@i+1 YU\k D
end vb9C
小记存储过程中经常用到的本周,本月,本年函数 k=O
Dateadd(wk,datediff(wk,0,getdate()),-1) 7}pg7EF3z
Dateadd(wk,datediff(wk,0,getdate()),6) FJn.V1
Dateadd(mm,datediff(mm,0,getdate()),0) nW
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O0eM*~zI
Dateadd(yy,datediff(yy,0,getdate()),0) -Q|]C{r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |FSp`P
上面的SQL代码只是一个时间段 hV
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Dateadd(wk,datediff(wk,0,getdate()),-1) @E>I<j,D
Dateadd(wk,datediff(wk,0,getdate()),6) /0XmU@B
就是表示本周时间段. ^zfs8]QSf
下面的SQL的条件部分,就是查询时间段在本周范围内的: #K!"/,d@>J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )^
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而在存储过程中 I^[[*Bh*C
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $ <3^( y
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) bL5u;iy)