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。 mG)8U{L
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一、基础 ]@X{dc
1、说明:创建数据库 47IY|Jdz
CREATE DATABASE database-name r6`\d k
2、说明:删除数据库 m0A# 6=<
drop database dbname upypxC
3、说明:备份sql server l'U1
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--- 创建 备份数据的 device AnNPTi
USE master akT|Y4KxD
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' s^w\zz Yb
--- 开始 备份 9ilM@SR
BACKUP DATABASE pubs TO testBack #{!O,`qD
4、说明:创建新表 -(*nSD9
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vwKw?Z0%J
根据已有的表创建新表: ]cIu|bRO
A:create table tab_new like tab_old (使用旧表创建新表) ~,ynJ]_aJB
B:create table tab_new as select col1,col2... from tab_old definition only ./l|8o
5、说明:删除新表 {odA[H
drop table tabname SIq1X'7
6、说明:增加一个列 .f>,6?
Alter table tabname add column col type Dg~
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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。 S5N@\ x
7、说明:添加主键: Alter table tabname add primary key(col) Is13:
说明:删除主键: Alter table tabname drop primary key(col) nv"G;W
8、说明:创建索引:create [unique] index idxname on tabname(col....) p8=|5.
删除索引:drop index idxname T2wv0sHlt
注:索引是不可更改的,想更改必须删除重新建。 {XtoiI
9、说明:创建视图:create view viewname as select statement ~r<p@k=.#0
删除视图:drop view viewname -kl;!:'.3
10、说明:几个简单的基本的sql语句 14H'!$
选择:select * from table1 where 范围 nbGoJC:U
插入:insert into table1(field1,field2) values(value1,value2) c45tmul
删除:delete from table1 where 范围 sAi&A9"*
更新:update table1 set field1=value1 where 范围 `(!NYx
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6lsL^]7
排序:select * from table1 order by field1,field2 [desc] *>k!hq;j
总数:select count as totalcount from table1 Q',m{;;
求和:select sum(field1) as sumvalue from table1
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平均:select avg(field1) as avgvalue from table1 gN?0m4[$i
最大:select max(field1) as maxvalue from table1 '[nmFCG%m*
最小:select min(field1) as minvalue from table1 wcZbmJ:
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11、说明:几个高级查询运算词 ==N` !+
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A: UNION 运算符 @`w n<%o$
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。 OV[`|<C '
B: EXCEPT 运算符 >
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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。 gg[9u-
C: INTERSECT 运算符 D`VFf\7
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。 p<KIF>rf|
注:使用运算词的几个查询结果行必须是一致的。 =_
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12、说明:使用外连接 xc;DdK=1X
A、left outer join: M)JADX
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。 KCUU#t|8V\
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 rB%y6P B
B:right outer join: |SQ|qbe=
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。 )11W)G`w
C:full outer join: QR"bYQ
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。 =&Xdm(
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二、提升 bLbR IY"l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 :CaTP% GW
法二:select top 0 * into b from a ZenPw1 -
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) S`iR9{+&
insert into b(a, b, c) select d,e,f from b; !>n|c$=;qk
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) #Fs|f3-@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &[_ZXVva~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P~RhUKfd
4、说明:子查询(表名1:a 表名2:b) -7%X]
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ^ve14mbF#.
5、说明:显示文章、提交人和最后回复时间 %d;<2b0
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b tnb$sulc+
6、说明:外连接查询(表名1:a 表名2:b) VFj(M
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /0lC KU!=
7、说明:在线视图查询(表名1:a ) S~)w\(r
select * from (SELECT a,b,c FROM a) T where t.a > 1; x<ax9{
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 M2@;RZ(|
select * from table1 where time between time1 and time2 ?n]FNjd
select a,b,c, from table1 where a not between 数值1 and 数值2 |~K(F<;j
9、说明:in 的使用方法 oM,- VUr
select * from table1 where a [not] in ('值1','值2','值4','值6') 2z_2.0/3
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3c #s|qW
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) WUEHB
11、说明:四表联查问题: \Q&,ISO\
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 ..... %8mm Hh
12、说明:日程安排提前五分钟提醒 VWi2(@R^
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 T3N"CUk
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 S1bAu
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14、说明:前10条记录 *Zbuq8>
select top 10 * form table1 where 范围 G[Tl%w
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.) cozXb$bBY
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) gU1 #`r>[)
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ,9of(T(~
(select a from tableA ) except (select a from tableB) except (select a from tableC) :243 H
17、说明:随机取出10条数据 ~R]35Cp-#
select top 10 * from tablename order by newid() "A3dvr
18、说明:随机选择记录 )TJS4?
select newid() }Qr6l/2
19、说明:删除重复记录 x83a!9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [}2Z/
20、说明:列出数据库里所有的表名 2.lgT|p
select name from sysobjects where type='U' GABQUmtH
21、说明:列出表里的所有的 PJLR<9
select name from syscolumns where id=object_id('TableName') ]@
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Yr+23Ro
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 7G93,dJ
显示结果: #X`8dnQZ
type vender pcs K84^Oq
电脑 A 1 ^G|98yc!'
电脑 A 1 S%mfs!E>
光盘 B 2 Ug%_@t/?
光盘 A 2 F{m{d?:OA
手机 B 3 1||+6bRP
手机 C 3 z[nS$]u
23、说明:初始化表table1 0g=`DSC<(
TRUNCATE TABLE table1 E167=BD9<
24、说明:选择从10到15的记录 iL]'y\?lv
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6'C2SihYp
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三、技巧 8g~EL{'
1、1=1,1=2的使用,在SQL语句组合时用的较多 q]% T:A=
"where 1=1" 是表示选择全部 "where 1=2"全部不选, T:iP="?{
如: _.V?A*
if @strWhere !='' Sq2P-y!w
begin ?1I GYyu!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3l1cyPv
end kkCZNQ~I
else 3Q By\1h.
begin HU ;#XU1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !mJo'K
end X/0v'N
我们可以直接写成 qu|i;WZE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ,h]o>
2、收缩数据库 'UU\4M
--重建索引 <skajQQ
DBCC REINDEX HMGB>
DBCC INDEXDEFRAG ,IHb+ K
--收缩数据和日志 FnFb[I@eu
DBCC SHRINKDB 'LE"#2Hu
DBCC SHRINKFILE {zLhiUH
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3、压缩数据库 3ec`Wa
dbcc shrinkdatabase(dbname) R^#@lI~
4、转移数据库给新用户以已存在用户权限 OE`X<h4r
exec sp_change_users_login 'update_one','newname','oldname' M8&}j
go C.Uju`3
5、检查备份集 pB:$lS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b~m2tC=AW
6、修复数据库 UUe#{6Jx_
ALTER DATABASE [dvbbs] SET SINGLE_USER $md%xmQ[
GO c=O,;lWFqm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w'T q3-%V
GO -~{c
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ALTER DATABASE [dvbbs] SET MULTI_USER g"VMeW^
GO dl-l"9~;
7、日志清除 b7`D|7D
SET NOCOUNT ON `:NaEF?Sj
DECLARE @LogicalFileName sysname, d3Mva,bw<
@MaxMinutes INT, G3i !PwW
@NewSize INT =+:{P?*}
USE tablename -- 要操作的数据库名 =='Td[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 J:*-gwv9*m
@MaxMinutes = 10, -- Limit on time allowed to wrap log. y046:@v(
@NewSize = 1 -- 你想设定的日志文件的大小(M) "SxLN
8.:
-- Setup / initialize pKUP2m`MW
DECLARE @OriginalSize int K5>p89mZ
SELECT @OriginalSize = size 2}6%qgnT-
FROM sysfiles 1{x.xi"A/
WHERE name = @LogicalFileName SLL3v,P(7
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /1UOT\8U
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #6v27:XK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 'dG%oDHX]P
FROM sysfiles ]}="m2S3
WHERE name = @LogicalFileName 2F{hg%
CREATE TABLE DummyTrans gV;H6"
(DummyColumn char (8000) not null) e}Vw!w
DECLARE @Counter INT, ^2D1`,|N
@StartTime DATETIME, n.MRz WJpZ
@TruncLog VARCHAR(255) )- 15 N
SELECT @StartTime = GETDATE(), S0,R_d')
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' CqMhk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Cwa^"r3P1
EXEC (@TruncLog) (& "su3z
-- Wrap the log if necessary. ipnV$!z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired HAz By\M{
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |077Sf|
AND (@OriginalSize * 8 /1024) > @NewSize s9;#!7ms
BEGIN -- Outer loop. 6 gL=u-2
SELECT @Counter = 0 Rk<@?(l!6x
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |~`as(@Ih
BEGIN -- update +d}E&=p_
INSERT DummyTrans VALUES ('Fill Log') kl!wVLE
DELETE DummyTrans O|IG_RL]
SELECT @Counter = @Counter + 1 BF*kb2"GZ6
END $
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EXEC (@TruncLog) tsOrt3
END MB^~%uZ2K
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 1J=.N|(@Q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + (/d5UIM{&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 94uNI8
FROM sysfiles ?liK\C2Z<
WHERE name = @LogicalFileName lz#GbXn.
DROP TABLE DummyTrans V]OmfPve
SET NOCOUNT OFF u-Ddq~;|
8、说明:更改某个表 hd\gH^wk
exec sp_changeobjectowner 'tablename','dbo' *K!|@h{60
9、存储更改全部表 G'2#9<c*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _/8FRkx
@OldOwner as NVARCHAR(128), :bV mgLgG
@NewOwner as NVARCHAR(128) ;h6v@)#GX
AS {^mNJ
DECLARE @Name as NVARCHAR(128) k(>h^
DECLARE @Owner as NVARCHAR(128) {e[%;W%c&
DECLARE @OwnerName as NVARCHAR(128) =!O*/6rz
DECLARE curObject CURSOR FOR Q)m4_+,d
select 'Name' = name, 0]KraLu"N
'Owner' = user_name(uid)
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from sysobjects T{wpJ"F5<]
where user_name(uid)=@OldOwner Ac2(O6
order by name q5h*`7f
OPEN curObject cMyiW$;
FETCH NEXT FROM curObject INTO @Name, @Owner Q$& sTM
WHILE(@@FETCH_STATUS=0) fH`P[^N
BEGIN fx=Awba
if @Owner=@OldOwner ,g-EW
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begin S=R7`a<.5
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +;$oJJ
exec sp_changeobjectowner @OwnerName, @NewOwner ](tx<3h
end +a&p$\
-- select @name,@NewOwner,@OldOwner /kL$4CA
FETCH NEXT FROM curObject INTO @Name, @Owner 5$DHn]
END Tus}\0/i>
close curObject |b-9b&
deallocate curObject `p;eIt
GO 0q>P~]Ow
10、SQL SERVER中直接循环写入数据 D']ZlB'K
declare @i int Wcb7
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set @i=1 ~!s-o|N_\
while @i<30 $vHU$lZ/W
begin 2LrJ>Mi
insert into test (userid) values(@i) ~$'\L
set @i=@i+1 Fc~'TBf,,`
end 'O5'i\uz
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) D3|oOOoG
Dateadd(wk,datediff(wk,0,getdate()),6) QM3,'?ekRH
Dateadd(mm,datediff(mm,0,getdate()),0) f|^dD`
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) tz#gClo
Dateadd(yy,datediff(yy,0,getdate()),0) X37 L\e[c
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ,yd
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上面的SQL代码只是一个时间段 FX9F"42@
Dateadd(wk,datediff(wk,0,getdate()),-1) SH*C"
Dateadd(wk,datediff(wk,0,getdate()),6) :[ k4Z]t8
就是表示本周时间段. 2*(Z==XC7
下面的SQL的条件部分,就是查询时间段在本周范围内的: u@ jX+\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) W_m"ySQs
而在存储过程中 `:P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [SJ6@q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) R@Gq)P9?