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。 8uP,#D<wZ
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一、基础 ,5mK_iUw3
1、说明:创建数据库 g1@zk$
CREATE DATABASE database-name SGXXv
2、说明:删除数据库 ]e$mTRi*
drop database dbname |cEJRs@B
3、说明:备份sql server hxP%m4xF +
--- 创建 备份数据的 device yS[:C
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USE master cV\(Z6u
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @i'RIL}
--- 开始 备份 ^ r-F@$:.
BACKUP DATABASE pubs TO testBack !TA6- ]1
4、说明:创建新表 *T-+Pm-Cq
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Oh3AbpTT
根据已有的表创建新表: v*Ds:1"H-I
A:create table tab_new like tab_old (使用旧表创建新表) 4/;hA
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B:create table tab_new as select col1,col2... from tab_old definition only ,)TtI~6Q
5、说明:删除新表 NoTEbFrV
drop table tabname eee77.@y-p
6、说明:增加一个列 P"Lk(gY
Alter table tabname add column col type E
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 4nK\gXz19
7、说明:添加主键: Alter table tabname add primary key(col) /{>$E>N;
说明:删除主键: Alter table tabname drop primary key(col) ELf cZfJ
8、说明:创建索引:create [unique] index idxname on tabname(col....) w#vSZbh
删除索引:drop index idxname GvSSi'q~B
注:索引是不可更改的,想更改必须删除重新建。 NRN3*YGo
9、说明:创建视图:create view viewname as select statement Px{Cvc
删除视图:drop view viewname $M{MOehZ
10、说明:几个简单的基本的sql语句 >L\$
选择:select * from table1 where 范围 H=Scrvfx
插入:insert into table1(field1,field2) values(value1,value2) Q97F5ru6
删除:delete from table1 where 范围 a\;1%2a
更新:update table1 set field1=value1 where 范围 q,`"Z)97
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! d` %8qLIW
排序:select * from table1 order by field1,field2 [desc] t5t,(^ ;f
总数:select count as totalcount from table1 QK% Nt
求和:select sum(field1) as sumvalue from table1 3<}\{ jT
平均:select avg(field1) as avgvalue from table1 q.0Evr:
最大:select max(field1) as maxvalue from table1 YXz*B5R
最小:select min(field1) as minvalue from table1 POvxZU
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11、说明:几个高级查询运算词 wJyrF
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A: UNION 运算符 ha[c<e]uo[
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Dl=9<:6FW
B: EXCEPT 运算符 W>f q 9
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 f@S n1c,Mk
C: INTERSECT 运算符 3y^PKIIrt
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 [v47_ 5O
注:使用运算词的几个查询结果行必须是一致的。 V"Cx5#\7C
12、说明:使用外连接 0lpkG
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A、left outer join: U*sjv6*T
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 {
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c J]&^A$
B:right outer join: (V&5EO8)
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。 (~>uFH
C:full outer join: CD^C}MB
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。 WX"iDz.
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二、提升 F/pq9
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) w8=&rzr8
法一:select * into b from a where 1<>1 L
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法二:select top 0 * into b from a /80H.|8O
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @JW HG1qJ
insert into b(a, b, c) select d,e,f from b; LZ#=Ks
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) NS<C"O
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 rX7GVg@H
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. sNaLz
4、说明:子查询(表名1:a 表名2:b) %x'}aTa
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) V}3'0
5、说明:显示文章、提交人和最后回复时间 cI Sugk~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @}, |i*H/
6、说明:外连接查询(表名1:a 表名2:b) 6ZO6O=KD
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :g%hT$,]3b
7、说明:在线视图查询(表名1:a ) q
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select * from (SELECT a,b,c FROM a) T where t.a > 1; m+UWvUB)
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 1.9bU/X
select * from table1 where time between time1 and time2 =Bg $OX
select a,b,c, from table1 where a not between 数值1 and 数值2 s5bqS'%
9、说明:in 的使用方法 Hs:0j$
select * from table1 where a [not] in ('值1','值2','值4','值6') r` B(ucE
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ,`Keqfx
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) kzE<Y
11、说明:四表联查问题: 4,,DA2^!
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 ..... 8Y]% S9.
12、说明:日程安排提前五分钟提醒 |,bP`Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 6i+<0b}!/
13、说明:一条sql 语句搞定数据库分页 m?<^b_a}
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 ^h$^j
14、说明:前10条记录 t[e]AU[}
select top 10 * form table1 where 范围 M zFFWk
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) /Nc)bF%gX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) YdZ9##IU3
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 |(%=zb=?X
(select a from tableA ) except (select a from tableB) except (select a from tableC) {q/;G!ON.S
17、说明:随机取出10条数据 216`rQ}z
select top 10 * from tablename order by newid() yhkKakg,)
18、说明:随机选择记录 YQ$LU\:
select newid() {Gr"lOi*@
19、说明:删除重复记录 A`--*$ 8\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) UX2@eyejQ7
20、说明:列出数据库里所有的表名 KE4#vKV0yC
select name from sysobjects where type='U' \#h{bnx
21、说明:列出表里的所有的 mm9uhlV8
select name from syscolumns where id=object_id('TableName') 0HO'%'Ga*
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。 _l"=#i@L
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 )Q 5 x%
显示结果: ;reBJk
type vender pcs i zYC0T9
电脑 A 1 }S$OE))u
电脑 A 1 x5Ue"RMl+
光盘 B 2 cL<,]%SkE
光盘 A 2 VbDk44X.W
手机 B 3 B"sB0NuT/$
手机 C 3 NQGa=kXeJ
23、说明:初始化表table1 U(PW$\l
TRUNCATE TABLE table1 ? 'qyI^m@
24、说明:选择从10到15的记录 l^XOW- ;u
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc r#A*{4wz
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三、技巧 VJ8'T"^Hf
1、1=1,1=2的使用,在SQL语句组合时用的较多 aNn4j_V(
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @M OaXe
如: I94-#*~I
if @strWhere !='' ;[79Ewd#$
begin l}iQ0v@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere jJaMkF;f
end 1S(n3(KRk$
else )@p?4XsT4J
begin ,J'_Vi
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8f<y~L_(`
end [K@(,/$
我们可以直接写成 /k[8xb
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere U {Knjo S
2、收缩数据库 v`c;1 ?=,q
--重建索引 n=PfV3B
DBCC REINDEX $bD`B'5
DBCC INDEXDEFRAG 0Vrs bkS
--收缩数据和日志 C0K:
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DBCC SHRINKDB 6uv~.-T<l
DBCC SHRINKFILE ,a?oGi
3、压缩数据库 ?E_;[(Mcr
dbcc shrinkdatabase(dbname) /\_n5XI1
4、转移数据库给新用户以已存在用户权限 0WfnX>(C7R
exec sp_change_users_login 'update_one','newname','oldname' C=|8C70[%N
go kt0xR)gU
5、检查备份集 $Mj\ 3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' V%)Tu{L
6、修复数据库 *7-rm
ALTER DATABASE [dvbbs] SET SINGLE_USER ).IyjHY
GO g1?9ge1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 7R7+jL,
GO 1<fW .Q)
ALTER DATABASE [dvbbs] SET MULTI_USER 5~/EAK`
GO -)B_o#2=2
7、日志清除 @D!*@M6
SET NOCOUNT ON jVLJqWP'!
DECLARE @LogicalFileName sysname, M|j=J{r
@MaxMinutes INT, #Q)r6V:
@NewSize INT lz::6}
USE tablename -- 要操作的数据库名 >d=pl}-kOQ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 wPm
@MaxMinutes = 10, -- Limit on time allowed to wrap log. n-xdyJD
@NewSize = 1 -- 你想设定的日志文件的大小(M) !4cY^4>o
-- Setup / initialize j}B86oX
DECLARE @OriginalSize int Zhv%mUj~
SELECT @OriginalSize = size '<YBoU{e*
FROM sysfiles iF Mf[qBg
WHERE name = @LogicalFileName ."=p\:^j*
SELECT 'Original Size of ' + db_name() + ' LOG is ' + G'p322Bu
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^e <E/j{~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .4 U*.Rf
FROM sysfiles mNacLkh[
WHERE name = @LogicalFileName Dw7Xy}I/
CREATE TABLE DummyTrans d@1^U9sf
(DummyColumn char (8000) not null) ^r.CUhx)
DECLARE @Counter INT, b}ya9tCl;
@StartTime DATETIME, 7n.Oem
@TruncLog VARCHAR(255) 1AN$s
SELECT @StartTime = GETDATE(), e3W~6P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7(X
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) f+hHc8g
EXEC (@TruncLog) Hnk&2bY
-- Wrap the log if necessary. _K!.TM+9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T}=^D=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rIJPgF
AND (@OriginalSize * 8 /1024) > @NewSize OR!W3
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BEGIN -- Outer loop. ni%)a
SELECT @Counter = 0 HnKgD:
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) jq*`| m;Q
BEGIN -- update H!Q72tyo
INSERT DummyTrans VALUES ('Fill Log') zD<W`_z
DELETE DummyTrans fV5$[CL1
SELECT @Counter = @Counter + 1 N'9T*&o+
END dH;2OWM
EXEC (@TruncLog) [8IO0lul+
END @-Ql6k
SELECT 'Final Size of ' + db_name() + ' LOG is ' + o.A:29KoU
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + RPgz"-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' +llb{~ZN
FROM sysfiles _Iav2=0Wi
WHERE name = @LogicalFileName [. 9[?8
DROP TABLE DummyTrans zA>X+JH>iw
SET NOCOUNT OFF kt)Et
8、说明:更改某个表 f+uyO7
exec sp_changeobjectowner 'tablename','dbo' 6{]F#ig=
9、存储更改全部表 F[Mwd &P@
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @QVg5
@OldOwner as NVARCHAR(128), f%@~|:G:
@NewOwner as NVARCHAR(128) r4X}U|s!0
AS o4WQA"VxM
DECLARE @Name as NVARCHAR(128) 0LH6G[
DECLARE @Owner as NVARCHAR(128)
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DECLARE @OwnerName as NVARCHAR(128) Y06^M?}
DECLARE curObject CURSOR FOR M=uT8JB
select 'Name' = name, iLuC_.'u=
'Owner' = user_name(uid) -i2rcH
from sysobjects Ge-Bk)6
where user_name(uid)=@OldOwner )/>BgXwH
order by name .6C/,rQ?c
OPEN curObject zvdut ,6<
FETCH NEXT FROM curObject INTO @Name, @Owner 7\2I>W
WHILE(@@FETCH_STATUS=0) {sC Ni
BEGIN e7@ m i
if @Owner=@OldOwner %5gdLm!p
begin oc( '!c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^%9oeT{
exec sp_changeobjectowner @OwnerName, @NewOwner n>q!m@ }<
end .A<Hk1(-)
-- select @name,@NewOwner,@OldOwner Q*>)W{H&)
FETCH NEXT FROM curObject INTO @Name, @Owner "Bf8mEmp
END b+|Jw\k
close curObject r9_ ON|
deallocate curObject M.mn9kw`
GO C(G.yd
10、SQL SERVER中直接循环写入数据 F1@Po1VTD
declare @i int T(*,nJi~9
set @i=1 2 3PRb<q
while @i<30 <3B^5p\/
begin #! R>`l(S
insert into test (userid) values(@i) /#Aw7F$Ey
set @i=@i+1 W`Gbo
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end |?^<=%
小记存储过程中经常用到的本周,本月,本年函数 bzNnEH`^]
Dateadd(wk,datediff(wk,0,getdate()),-1) n]IF`kYQV
Dateadd(wk,datediff(wk,0,getdate()),6) 3E|||3rf
Dateadd(mm,datediff(mm,0,getdate()),0) H:~p5t
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O0#[hY,
Dateadd(yy,datediff(yy,0,getdate()),0) lrv-[}}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \yJ
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上面的SQL代码只是一个时间段 Z\IM~-
Dateadd(wk,datediff(wk,0,getdate()),-1) k-|g
Dateadd(wk,datediff(wk,0,getdate()),6) CXrOb+
就是表示本周时间段. 7@;*e=v
下面的SQL的条件部分,就是查询时间段在本周范围内的: ['}|#3*w
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) zas&gsl-;
而在存储过程中 kzZgNv#G;
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `Ow]@flLI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1YV1Xnn,