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。 E 8W*^^z(
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一、基础 #]i^L;u1A
1、说明:创建数据库 jZ5ac=D&I
CREATE DATABASE database-name obbg#,
2、说明:删除数据库 2|exY>`w
drop database dbname + rN#
3、说明:备份sql server \C;Yn6PK0
--- 创建 备份数据的 device L*Ffic
USE master >W/mRv&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' j1Sjw6}GCH
--- 开始 备份 w"M!**bP
BACKUP DATABASE pubs TO testBack 4M>]0%3.D
4、说明:创建新表 mrsN@(X0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) $i8oLSRV
根据已有的表创建新表: %|/\Qu
A:create table tab_new like tab_old (使用旧表创建新表) d\A7}_r*x
B:create table tab_new as select col1,col2... from tab_old definition only ~Odclrs
5、说明:删除新表 &BKnJ{,H
drop table tabname U[yA`7Zs}
6、说明:增加一个列 ~QE?GL
Alter table tabname add column col type {Ho _U&<
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。 x` wUi*G
7、说明:添加主键: Alter table tabname add primary key(col) 7PfNPz<4+
说明:删除主键: Alter table tabname drop primary key(col) a&mL Dh/
8、说明:创建索引:create [unique] index idxname on tabname(col....) [UdJ(cGf
删除索引:drop index idxname t]3:vp5N]
注:索引是不可更改的,想更改必须删除重新建。 3,#qt}8`
9、说明:创建视图:create view viewname as select statement S>HfyZ&Pc
删除视图:drop view viewname }{J>kgr6
10、说明:几个简单的基本的sql语句 4yMi9Ri4H
选择:select * from table1 where 范围 5``usn/&Kj
插入:insert into table1(field1,field2) values(value1,value2) vsA/iH.
删除:delete from table1 where 范围 Q}lY1LT`
更新:update table1 set field1=value1 where 范围 %AT/g&M&1#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
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排序:select * from table1 order by field1,field2 [desc] -yIx:*KI
总数:select count as totalcount from table1 n]l3
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求和:select sum(field1) as sumvalue from table1 7we='L&R
平均:select avg(field1) as avgvalue from table1 / 8dRql-Ne
最大:select max(field1) as maxvalue from table1 M>BVnB_,-
最小:select min(field1) as minvalue from table1 ms&5Bq+9
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11、说明:几个高级查询运算词 2B6y1" B
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A: UNION 运算符 lYm00v6y
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。 0|\A5
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B: EXCEPT 运算符 nGJ+.z
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。 U;
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C: INTERSECT 运算符 33"!K>wC
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。 =ZV+*cCC=q
注:使用运算词的几个查询结果行必须是一致的。 dt=M#+g
12、说明:使用外连接 lH,/N4r*&
A、left outer join: [m<8SOMG(
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。 C1YH\X(r
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|s|Wmx>u
B:right outer join: a|dn3R>vX
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。 +9;6]4
C:full outer join: C2hB7?UGN
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。 >IKIe
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二、提升 7;#o?6!7
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PMj!T \B|
法一:select * into b from a where 1<>1 $U^ Ms!'L
法二:select top 0 * into b from a V1,4M _Z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) xiC.M6/
insert into b(a, b, c) select d,e,f from b; @&Af[X4s
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ){tTB
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 gHH[QLD=I
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. IV`+B<3
4、说明:子查询(表名1:a 表名2:b) Jd|E
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) #("E)P
5、说明:显示文章、提交人和最后回复时间 }f6_7W%5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b *@ S+J$
6、说明:外连接查询(表名1:a 表名2:b) DnB :~&Dw
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c \VAS<?3
7、说明:在线视图查询(表名1:a ) 2;SiH]HNS
select * from (SELECT a,b,c FROM a) T where t.a > 1; 0n?^I>j
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 +'g~3A-G
select * from table1 where time between time1 and time2 -0*z"a9<p8
select a,b,c, from table1 where a not between 数值1 and 数值2 DL '{
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9、说明:in 的使用方法 7*Gg#XQ>(
select * from table1 where a [not] in ('值1','值2','值4','值6') vri<R8
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?j8_j
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) YipL_&-
11、说明:四表联查问题: Bv}i#D
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 ..... N/B-u)?\:
12、说明:日程安排提前五分钟提醒 <q4<3A
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
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13、说明:一条sql 语句搞定数据库分页 |s !7U
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 [@$t35t~
14、说明:前10条记录 [:{HX U7y
select top 10 * form table1 where 范围 U,\t2z
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Y)C!N$=@Q
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZlL]AD@
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 ~5~Cpu2v7
(select a from tableA ) except (select a from tableB) except (select a from tableC) a7fn{VU8
17、说明:随机取出10条数据 _$gP-J
select top 10 * from tablename order by newid() @w;&:J9m
18、说明:随机选择记录 P[gYENQ
select newid() kK]L(ZU+
19、说明:删除重复记录 M+M\3U
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) F*,RDM'M
20、说明:列出数据库里所有的表名 sH{(=N
select name from sysobjects where type='U' /o nZ14
21、说明:列出表里的所有的 mv`ND&
select name from syscolumns where id=object_id('TableName') 14 hE<u
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Sh U1RQk
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type zW ; sr.
显示结果: pJ@D}2u(
type vender pcs '!XVz$C
电脑 A 1 oMb@)7
电脑 A 1 kfs[*ku
光盘 B 2 Uj)`(}r
光盘 A 2 zhC5%R &n/
手机 B 3 SGLU7*sfd
手机 C 3 ,D{D
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23、说明:初始化表table1 -j}zr yG-
TRUNCATE TABLE table1 f;a55%3c
24、说明:选择从10到15的记录 B d?{ldg
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 3TnrPO1E
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三、技巧 u'"]{.K>fb
1、1=1,1=2的使用,在SQL语句组合时用的较多 }m.45n/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, GsNZr=;C
如: .vtV2lq
if @strWhere !='' Uf\U~wM<
begin $xq$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 9at_F'>R
end I73=PfS:m
else 2j-^F
begin T5+9#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' bG!/%,s
end :Mnl 1;oh
我们可以直接写成 d`J~w/]
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 5P![fX|5
2、收缩数据库 v4X)R
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--重建索引 yz^Rm2$f9
DBCC REINDEX mW 'sdb
DBCC INDEXDEFRAG '0jn|9l58
--收缩数据和日志 Dq9*il;'
DBCC SHRINKDB rc7^~S]5
DBCC SHRINKFILE *L#\#nh7
3、压缩数据库 AP/#?
dbcc shrinkdatabase(dbname) PI$K+}E
4、转移数据库给新用户以已存在用户权限 ~y8KQ-1n"
exec sp_change_users_login 'update_one','newname','oldname' wp>L}!
go t,308Z
5、检查备份集 zIbrw9G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6[&x7"
6、修复数据库 =]W[{@P
ALTER DATABASE [dvbbs] SET SINGLE_USER f2Z(hYH~
GO 9%^O-8!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AkVgFQg"
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GO \vqqs
ALTER DATABASE [dvbbs] SET MULTI_USER k[5:]5lp+
GO E8b:MY
7、日志清除 aJ$({ZN\#
SET NOCOUNT ON jF0>wm
DECLARE @LogicalFileName sysname, &[y+WrGG
@MaxMinutes INT, e#z#bz2<
@NewSize INT $'93:9tg
USE tablename -- 要操作的数据库名 wYN/ }>M
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3?bTs =
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N<T@GQwkS
@NewSize = 1 -- 你想设定的日志文件的大小(M) NbUbLzE
-- Setup / initialize Eanwk` Rx
DECLARE @OriginalSize int "{M?,jP#
SELECT @OriginalSize = size v]hu5t
FROM sysfiles O{ |Ug~
WHERE name = @LogicalFileName #=
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + k83S.*9Mx
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L=V.@?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' WXe]Q bg
FROM sysfiles Mk!bmFZOZ
WHERE name = @LogicalFileName #]@|mf
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CREATE TABLE DummyTrans &r1]A&
(DummyColumn char (8000) not null) O*ER3
DECLARE @Counter INT, L4or*C^3
@StartTime DATETIME, B PG&R
@TruncLog VARCHAR(255) WM9z~z'2a
SELECT @StartTime = GETDATE(), EM,=R
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' y=SVS3D
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7(C:ty9
EXEC (@TruncLog) #X qnH
-- Wrap the log if necessary. HlraOp+
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired yVgHu#?PM
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (W+aeB0
AND (@OriginalSize * 8 /1024) > @NewSize kt7x}F(?<
BEGIN -- Outer loop. EjP9/VG@=
SELECT @Counter = 0 l9f%?<2D
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) xt1\Sie
BEGIN -- update 5Tq*]ZE
INSERT DummyTrans VALUES ('Fill Log') I9*BTT]
DELETE DummyTrans 3_ko=& B$
SELECT @Counter = @Counter + 1 (ty&$
END 5+a5pC
EXEC (@TruncLog) >Xw0i\G
END =TJ9Gr/R&:
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hr3<vWAD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + puox^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $) m$c5!
FROM sysfiles '+7"dHLC;
WHERE name = @LogicalFileName 1G)I|v9R
DROP TABLE DummyTrans w/csLi.O
SET NOCOUNT OFF 2 :wgt
8、说明:更改某个表 4OFv#$[
exec sp_changeobjectowner 'tablename','dbo' 1h?QEZ,6a
9、存储更改全部表 }Dx.;0*:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /cZTj!M
@OldOwner as NVARCHAR(128), }/MmuPp
@NewOwner as NVARCHAR(128) lESv
AS ^o4](l
DECLARE @Name as NVARCHAR(128) &1ZUMc
DECLARE @Owner as NVARCHAR(128) oqbhb1D1<
DECLARE @OwnerName as NVARCHAR(128) >35W{d
DECLARE curObject CURSOR FOR H`1q8}m
select 'Name' = name, =:'\wx
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'Owner' = user_name(uid) k{D0&
from sysobjects st)qw]Dn;Y
where user_name(uid)=@OldOwner i@mS8%|l
order by name i(>
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OPEN curObject 3!vnSX(iv
FETCH NEXT FROM curObject INTO @Name, @Owner "v/Yw'!
)
WHILE(@@FETCH_STATUS=0) P|t2%:_
BEGIN o+Fm+5t;
if @Owner=@OldOwner Ako]34Rl,
begin IYv.~IQO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) CV)K=Br5&_
exec sp_changeobjectowner @OwnerName, @NewOwner a9NIK/9
end "EwzuM8f
-- select @name,@NewOwner,@OldOwner 8J:=@X^}
FETCH NEXT FROM curObject INTO @Name, @Owner % _nmv
END D~ n-;T
close curObject R]3j6\
deallocate curObject Yz#E0aTTA
GO _ Y7Um
10、SQL SERVER中直接循环写入数据 g)7@EU2
declare @i int X0]{8v%
set @i=1 ~ +h4i'
while @i<30 G|u)eW
begin wsB
insert into test (userid) values(@i) "RgP!
set @i=@i+1 AkCy
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end a(X V~o
小记存储过程中经常用到的本周,本月,本年函数 l+j
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Dateadd(wk,datediff(wk,0,getdate()),-1) ,0{x-S0jX<
Dateadd(wk,datediff(wk,0,getdate()),6) <<R2
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Dateadd(mm,datediff(mm,0,getdate()),0) w |abaMam
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7^tYtMm|U
Dateadd(yy,datediff(yy,0,getdate()),0) i|m8#*Hd
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) _qk
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上面的SQL代码只是一个时间段 ld3H"p rR
Dateadd(wk,datediff(wk,0,getdate()),-1) EvH/d4V;
Dateadd(wk,datediff(wk,0,getdate()),6) Vh>|F}%E
就是表示本周时间段. u U%Z%O
下面的SQL的条件部分,就是查询时间段在本周范围内的: QseV\; z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ZG-#YF.1
而在存储过程中 sR/y|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) NF7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) EP^qj j@M