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。 q&Wwtqc9
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一、基础 P&0cF{
1、说明:创建数据库 lhl0
CREATE DATABASE database-name Ko)T>8:
2、说明:删除数据库 T zYgH
drop database dbname 43=-pyp
3、说明:备份sql server ?]D+H%3[$i
--- 创建 备份数据的 device o%PoSZZ
USE master Z4ov
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' So%1RY{)
--- 开始 备份 G@EjWZQ
BACKUP DATABASE pubs TO testBack sFCs_u1tNN
4、说明:创建新表 j :Jdwf
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) E)wT+\
根据已有的表创建新表: zl
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A:create table tab_new like tab_old (使用旧表创建新表) ( L\G!pP.
B:create table tab_new as select col1,col2... from tab_old definition only s4`*0_n
5、说明:删除新表 |/=p
drop table tabname n UCk0:{
6、说明:增加一个列 YCBML!L
Alter table tabname add column col type rqe_zyc&
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。 6XL9
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7、说明:添加主键: Alter table tabname add primary key(col) >ha Ixs`9
说明:删除主键: Alter table tabname drop primary key(col) zMzf=~
8、说明:创建索引:create [unique] index idxname on tabname(col....) b%f2"e0g
删除索引:drop index idxname 1=5'R/k
注:索引是不可更改的,想更改必须删除重新建。 zRoEx1
9、说明:创建视图:create view viewname as select statement x ETVtq
删除视图:drop view viewname R
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10、说明:几个简单的基本的sql语句 zw0 r
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选择:select * from table1 where 范围 W#7-%oT
插入:insert into table1(field1,field2) values(value1,value2) ;:\,x
删除:delete from table1 where 范围 lEbR) B,
更新:update table1 set field1=value1 where 范围 il cy/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1qKxg
排序:select * from table1 order by field1,field2 [desc] k>;r9^D
总数:select count as totalcount from table1 1fhK{9#
求和:select sum(field1) as sumvalue from table1 YZ:'8<
平均:select avg(field1) as avgvalue from table1 2a(yR>#
最大:select max(field1) as maxvalue from table1 Ldj^O9p(
最小:select min(field1) as minvalue from table1 Xa%&.&V
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11、说明:几个高级查询运算词 $CwTNm?
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A: UNION 运算符 _KhEwd
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 &T/q0bwd
B: EXCEPT 运算符 l^y?L4hg)
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 QRZTT qG
C: INTERSECT 运算符 vQTQS[R=z
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 (=tF2YBV
注:使用运算词的几个查询结果行必须是一致的。 ><
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12、说明:使用外连接 tTh;.88Z{
A、left outer join: 0CVsDVA
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 \%?8jQ'tX
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c t"bPKFRy9E
B:right outer join: b}*@=X=4o
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ))69a
C:full outer join: ])ALAAIc-
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 GE8D3V;*V
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二、提升 %=mwOoMk0L
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) C|~JPcl
法一:select * into b from a where 1<>1 "K$ Wh1<7
法二:select top 0 * into b from a %f>
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) [cLU*:
insert into b(a, b, c) select d,e,f from b; =.f +}y
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) >5~Zr$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 iI@Gyq=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. am'p^Z@
4、说明:子查询(表名1:a 表名2:b) 6[3Ioh
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) Zj+}T
5、说明:显示文章、提交人和最后回复时间 Vq)gpR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X6N]gD
6、说明:外连接查询(表名1:a 表名2:b) V.QzMF"o
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c L3=YlX`UL
7、说明:在线视图查询(表名1:a ) <&Y}j&(
select * from (SELECT a,b,c FROM a) T where t.a > 1; >gZk
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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 gC_s\WU
select * from table1 where time between time1 and time2 6(q`Oj
select a,b,c, from table1 where a not between 数值1 and 数值2 o|^?IQ7bpf
9、说明:in 的使用方法 3VRZM@i
select * from table1 where a [not] in ('值1','值2','值4','值6')
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 B-ri}PA
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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11、说明:四表联查问题: Th;gps%b
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 ..... Z/6'kE{l
12、说明:日程安排提前五分钟提醒 K'{W9~9Lq
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 LnI{S{]wDh
13、说明:一条sql 语句搞定数据库分页 ~q]|pD"\K|
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 :af;yu
14、说明:前10条记录 "U5Ln2X{J
select top 10 * form table1 where 范围 hNq8
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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.) 5Ckk5b
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) C>`.J_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 v1X&p\[d
(select a from tableA ) except (select a from tableB) except (select a from tableC) zmL~]!~&
17、说明:随机取出10条数据 \BbOljM=
select top 10 * from tablename order by newid() bUAR<R'E
18、说明:随机选择记录 ?;r8SowZ7
select newid() X.T\=dm%v
19、说明:删除重复记录 =6Kv`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =S[FJaIu7
20、说明:列出数据库里所有的表名 {7Gx9(
select name from sysobjects where type='U' 8F`BJ6='
21、说明:列出表里的所有的 (4{ C7
select name from syscolumns where id=object_id('TableName') srChY&h?<
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。 ll<9f)
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 z7t'6Fy9'
显示结果: ;oY(I7
type vender pcs s7UhC.>'@
电脑 A 1 JJ
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电脑 A 1 e1 {t0f
光盘 B 2 B~_,>WG
光盘 A 2 cpF1Xp vT
手机 B 3 5}d/8tS
手机 C 3 kh>SrW]B%
23、说明:初始化表table1 '!yS72{$2
TRUNCATE TABLE table1 {sna)v$;
24、说明:选择从10到15的记录 FUzMc1zy|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [N+ m5{tT
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三、技巧 68J 9T^84
1、1=1,1=2的使用,在SQL语句组合时用的较多 /XW&q)z-Hl
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dY4k9p8
如: lZS_n9Sc
if @strWhere !='' Xew1LPI
begin 9Ew:.&d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Re kb?|{z
end /+x#V!zM
else wzDk{4U
begin c+Q.?vJ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t4jd
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end j5,^9'
我们可以直接写成 dK J@{d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere N"Qg\PS_
2、收缩数据库 MG7 ?N #
--重建索引 <fC@KY>#
DBCC REINDEX 2qs>Bshf
DBCC INDEXDEFRAG H[BD)
--收缩数据和日志 E-yT
DBCC SHRINKDB O6m.t%*
DBCC SHRINKFILE L25kh}Q#7
3、压缩数据库 E ;BPN
dbcc shrinkdatabase(dbname) sJ))<,e5I
4、转移数据库给新用户以已存在用户权限 [K cki+
exec sp_change_users_login 'update_one','newname','oldname' AfbB~Ll Bq
go v"P&`1=T
5、检查备份集 Pl rkgS0J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' F`Dg*O
6、修复数据库 ]^J+-c
ALTER DATABASE [dvbbs] SET SINGLE_USER v`#j
GO ,:#,}w_HyO
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !US8aT
GO c;:">NR
ALTER DATABASE [dvbbs] SET MULTI_USER \)OZUch
GO u* t,i`
7、日志清除 NJ;"jQ-
SET NOCOUNT ON 8
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DECLARE @LogicalFileName sysname, jd%Len&p
@MaxMinutes INT, nS_Ta
@NewSize INT @~m=5C
USE tablename -- 要操作的数据库名 <Rcu%&;i
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [[R7~.;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {]wIM^$6+
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,?l~rc
-- Setup / initialize _j:UGMTi(U
DECLARE @OriginalSize int ;{<aA 5
SELECT @OriginalSize = size q,[k7&HS
FROM sysfiles C`\9cej
WHERE name = @LogicalFileName ,HFs.9#&B
SELECT 'Original Size of ' + db_name() + ' LOG is ' + uh]"(h(>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + z$JX'(<Z7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Y/.AUN
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FROM sysfiles {Ge+O<mD
WHERE name = @LogicalFileName si_W:mLF{a
CREATE TABLE DummyTrans c |>=S)|
(DummyColumn char (8000) not null) 21r==
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DECLARE @Counter INT, '3A+"k-}mh
@StartTime DATETIME, 2O
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@TruncLog VARCHAR(255) K(<$.
SELECT @StartTime = GETDATE(), 8zhBA9Y#~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 9n1ZVP.ag
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "(s6aqO$
EXEC (@TruncLog) K&=D-50%
-- Wrap the log if necessary. PJzc=XPU
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^_v[QV
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) AY#wVy
AND (@OriginalSize * 8 /1024) > @NewSize t)YUPDQ@J
BEGIN -- Outer loop. <fN;
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SELECT @Counter = 0 *)u?~r(F
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5L8&/EN9-
BEGIN -- update ^:`oP"%-T
INSERT DummyTrans VALUES ('Fill Log') ~12_D'8D[
DELETE DummyTrans "`pNH'
SELECT @Counter = @Counter + 1 S]}}A
END n.*3,4.]
EXEC (@TruncLog) \tY"BC4.
END i+g~ Uj}h
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,V,f2W 4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + $@_{p*q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 93j{.0]X
FROM sysfiles M\Se_
WHERE name = @LogicalFileName a 6%@d_A
DROP TABLE DummyTrans bW53" `X
SET NOCOUNT OFF v?L
8、说明:更改某个表 [ `7%sn]$
exec sp_changeobjectowner 'tablename','dbo' 3UdU"d[75
9、存储更改全部表 v:E;^$6Vn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Yu'a<5f
@OldOwner as NVARCHAR(128), L>dkrr)e
@NewOwner as NVARCHAR(128) 74+A+SK[
AS (S`6Q
DECLARE @Name as NVARCHAR(128) zDD4m`2
DECLARE @Owner as NVARCHAR(128) aX;A==>
DECLARE @OwnerName as NVARCHAR(128) hk%k(^ekU]
DECLARE curObject CURSOR FOR Hou*lCA
select 'Name' = name, t8QRi!\=
'Owner' = user_name(uid) F|>05>8
from sysobjects |( G2K'Ab
where user_name(uid)=@OldOwner B
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order by name T-'~? [v
OPEN curObject ow$q7uf
FETCH NEXT FROM curObject INTO @Name, @Owner kY"KD22a
WHILE(@@FETCH_STATUS=0) F$Hx`hoy
BEGIN 69-:]7.g
if @Owner=@OldOwner #)o7"PW:
begin CK0l9#g
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 3X;{vO\a1
exec sp_changeobjectowner @OwnerName, @NewOwner 8'A72*dhX
end >H>gH2qp
-- select @name,@NewOwner,@OldOwner q/NY72tj0
FETCH NEXT FROM curObject INTO @Name, @Owner #EDEYEW7
END 9Hd;353Q
close curObject !;S"&mcPDJ
deallocate curObject
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GO R_^/,^1
10、SQL SERVER中直接循环写入数据 0"78/6XIs
declare @i int _T5)n=|
set @i=1
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while @i<30 /.Fj.6U5
begin _%~$'Hy
insert into test (userid) values(@i) 54{q.I@n
set @i=@i+1 +`B'r
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end 3uV4/%U
小记存储过程中经常用到的本周,本月,本年函数 w7FoL
Dateadd(wk,datediff(wk,0,getdate()),-1) oKA& An
Dateadd(wk,datediff(wk,0,getdate()),6) ^rL_C}YBj-
Dateadd(mm,datediff(mm,0,getdate()),0) %y&]'A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <_Eg?ePW#
Dateadd(yy,datediff(yy,0,getdate()),0) Ye5jB2Z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) $d/&k`
上面的SQL代码只是一个时间段 } XR:2
Dateadd(wk,datediff(wk,0,getdate()),-1) .m;G$X|3U
Dateadd(wk,datediff(wk,0,getdate()),6) )55\4<ty
就是表示本周时间段. 2#vv$YD
下面的SQL的条件部分,就是查询时间段在本周范围内的: `pL^}_>|GM
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Zp&@h-%YoD
而在存储过程中 9XLFHV("
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S|em[D[Y^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) /*$hx @ih