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。 tZ=E')!\
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一、基础 QMa;Gy
1、说明:创建数据库 k. MUdU^
CREATE DATABASE database-name n[ T[DCQ,
2、说明:删除数据库 p7veQ`yNc
drop database dbname *BR~}1
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3、说明:备份sql server ;>
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--- 创建 备份数据的 device ORyE`h
USE master NO|KVZ~
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9N9L}k b
--- 开始 备份 S{PJUAu
BACKUP DATABASE pubs TO testBack {["\.ZS|
4、说明:创建新表 ?u/@PR\D
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) pP*zq"o
根据已有的表创建新表: C\/xl#e<@
A:create table tab_new like tab_old (使用旧表创建新表) co~Pyj
B:create table tab_new as select col1,col2... from tab_old definition only :=/85\P0SU
5、说明:删除新表 i@P)a'W_
drop table tabname <,Ue
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6、说明:增加一个列 ?ooe'V@
Alter table tabname add column col type wfU7G[
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。 eqP&8^HP
7、说明:添加主键: Alter table tabname add primary key(col) "^w]_^GD$d
说明:删除主键: Alter table tabname drop primary key(col)
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8、说明:创建索引:create [unique] index idxname on tabname(col....) q*\x0"mS/
删除索引:drop index idxname p<TpK )
注:索引是不可更改的,想更改必须删除重新建。 ?]Pmxp
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9、说明:创建视图:create view viewname as select statement CN#+U,NZV
删除视图:drop view viewname lsNrAA%m
10、说明:几个简单的基本的sql语句 ;3d"wW]}7K
选择:select * from table1 where 范围 FME3sa$
插入:insert into table1(field1,field2) values(value1,value2) a:"Uh**
删除:delete from table1 where 范围 ^* J2'X38I
更新:update table1 set field1=value1 where 范围 S0~2{G"v
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =U #dJ^4P
排序:select * from table1 order by field1,field2 [desc] CK,7^U
总数:select count as totalcount from table1 _d"b;4l
求和:select sum(field1) as sumvalue from table1 ^HV>`Pjd}=
平均:select avg(field1) as avgvalue from table1 (eCJ;%%k
最大:select max(field1) as maxvalue from table1 }`W){]{kO
最小:select min(field1) as minvalue from table1 p[hZ@f(z
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11、说明:几个高级查询运算词 :p]'32FA!
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A: UNION 运算符 : YXX8|>
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。 AG!w4Ky`
B: EXCEPT 运算符 Cnbz=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。 :bz}c48%
C: INTERSECT 运算符 [z9`)VIe
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。 "}pNe"ok
注:使用运算词的几个查询结果行必须是一致的。 \hBG<nH{0
12、说明:使用外连接 NdL,F;^
A、left outer join: 62 O.?Ij
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。 7B!xT2{T
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 k"NVV$;
B:right outer join: DE%KW:Hug
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ~-EOjX(X'E
C:full outer join: K[ (NTp$E
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。 <F}_ /q1
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二、提升 A%`[mc]4#
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 1#.>a$>
法二:select top 0 * into b from a Z @^9PQG$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) J3n-`k8
insert into b(a, b, c) select d,e,f from b; ]}U*_rM:
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) JsDpy{q
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 W#KpPDgZE
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `Jzp Sw
4、说明:子查询(表名1:a 表名2:b) @&X|5p"[g
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) _59huC.
5、说明:显示文章、提交人和最后回复时间 p1&b!*o- &
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7g%E`3)"
6、说明:外连接查询(表名1:a 表名2:b) Z?%zgqTXb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c i%/Jp[e\W>
7、说明:在线视图查询(表名1:a ) tS|(K=$
select * from (SELECT a,b,c FROM a) T where t.a > 1; Wn(6,MDUN
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 xL{a
select * from table1 where time between time1 and time2 R $&o*K`?
select a,b,c, from table1 where a not between 数值1 and 数值2 {5F-5YL+>
9、说明:in 的使用方法 KO]T<R
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select * from table1 where a [not] in ('值1','值2','值4','值6') u/M+u;
10、说明:两张关联表,删除主表中已经在副表中没有的信息 F )W:
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) huJ&]"C
11、说明:四表联查问题: kg'o&^/=
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 ..... Fxm$9(Y
12、说明:日程安排提前五分钟提醒 t0IEaj75c
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %d?cP}V
13、说明:一条sql 语句搞定数据库分页 @>p<3_Y1
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 {buo^kgj`]
14、说明:前10条记录 .w0s%T,8}^
select top 10 * form table1 where 范围 ~g5[$r-u-u
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.) n2oz"<?$S
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 4|CtRF<L
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 P*I}yPeb
(select a from tableA ) except (select a from tableB) except (select a from tableC) .
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17、说明:随机取出10条数据 yt.F\ [1
select top 10 * from tablename order by newid() H^s<{E0<
18、说明:随机选择记录 eD*A)
select newid() jpO7'ivG
19、说明:删除重复记录 hRK/T7v
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ZuS0DPS`L
20、说明:列出数据库里所有的表名 UE$UR#T'w
select name from sysobjects where type='U' )?X-(4
21、说明:列出表里的所有的 80Gn%1A9
select name from syscolumns where id=object_id('TableName') 0l-Ef1
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。 @te!Jgu{
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 Z@]e{zO
显示结果: +\F'iAs@
type vender pcs ,u`B<heoLU
电脑 A 1 L{h%f4Du#
电脑 A 1 %Ti}CwI`
光盘 B 2
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光盘 A 2 ^yyC
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手机 B 3 K':K{ee>
手机 C 3 DX"xy
23、说明:初始化表table1 >g+?Oebgw
TRUNCATE TABLE table1 <N_+=_
24、说明:选择从10到15的记录 @U3Vc|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^eR%N8Z
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三、技巧 }Rz3<eON
1、1=1,1=2的使用,在SQL语句组合时用的较多 n&-qaoNl
"where 1=1" 是表示选择全部 "where 1=2"全部不选, E}40oID
如: Qzlo'e1
if @strWhere !='' n#wI@W>%+
begin pO ml8SQf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >i5acuth
end rmE" rf
else
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begin -lhLA`6_R
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,]+z)
end 1#0{@35
我们可以直接写成 ~[\_N\rm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere DR c)iE>@
2、收缩数据库 ],Rd ySN&
--重建索引 uoXAQ6k
DBCC REINDEX .h>8@5/s
DBCC INDEXDEFRAG WnGGo'Z
--收缩数据和日志 6bBB/yd
DBCC SHRINKDB |=$-Wu
DBCC SHRINKFILE )w0AC"2O~
3、压缩数据库 0 0M@
dbcc shrinkdatabase(dbname) A9kzq_3
4、转移数据库给新用户以已存在用户权限 qU#BJON]BR
exec sp_change_users_login 'update_one','newname','oldname' sK7+Q
go 8[J}CdS
5、检查备份集 ^d~1E Er
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' OnK~3j
6、修复数据库 wAxrc+
ALTER DATABASE [dvbbs] SET SINGLE_USER uU:CR>=AKW
GO US%^#D q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~d6DD;`K
GO rwG CUo6Z
ALTER DATABASE [dvbbs] SET MULTI_USER |j VM&R2s
GO RW }"2
7、日志清除 '*k'i;2/1
SET NOCOUNT ON ^1L>l9F
DECLARE @LogicalFileName sysname, iTV) NsC}
@MaxMinutes INT, )I$q 5%q8
@NewSize INT ODC8D>ZYl
USE tablename -- 要操作的数据库名 ijdXU8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 y!!E\b=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?HV`|
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@NewSize = 1 -- 你想设定的日志文件的大小(M) I<8sI%,s
-- Setup / initialize Ko/ I#)
DECLARE @OriginalSize int N~NQ6:R[
SELECT @OriginalSize = size cPU/tkc
FROM sysfiles IrWD%/$H
WHERE name = @LogicalFileName E4W zU
SELECT 'Original Size of ' + db_name() + ' LOG is ' + LJ(1RK GCz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + mUz\ra;z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "eWYv3z~-
FROM sysfiles K.z64/H:
WHERE name = @LogicalFileName ]/B$br'O{?
CREATE TABLE DummyTrans Iz{R}#8CZ
(DummyColumn char (8000) not null) `UQf2o0%3w
DECLARE @Counter INT, 9gEssTkts
@StartTime DATETIME, !DI{:I_h(
@TruncLog VARCHAR(255) ,+
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SELECT @StartTime = GETDATE(), NSFs\a@1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {|yob4N
DBCC SHRINKFILE (@LogicalFileName, @NewSize) bgK<pi)d
EXEC (@TruncLog) n]u<!.X
-- Wrap the log if necessary. n9\]S7]52
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired jOyvDY9\
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ocyb5j
AND (@OriginalSize * 8 /1024) > @NewSize .]9c /
BEGIN -- Outer loop. yx<WSgWZ[
SELECT @Counter = 0 G_dsrpI=N
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) d)"?mD:m/M
BEGIN -- update l?q%?v8
INSERT DummyTrans VALUES ('Fill Log') ~(@ E`s&{
DELETE DummyTrans X K5<Tg
SELECT @Counter = @Counter + 1 )
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END e[Jem5C
EXEC (@TruncLog) [M%9_CfZOy
END i9D0]3/>
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !!:LJ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Dr~=o%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' f(eQ+0D
FROM sysfiles dna6QV>A
WHERE name = @LogicalFileName ?9X&tK)E-
DROP TABLE DummyTrans QERU5|.wc
SET NOCOUNT OFF {q3H5csFq
8、说明:更改某个表 NKmoG\*
exec sp_changeobjectowner 'tablename','dbo' `+/H^
9、存储更改全部表 DS-fjH\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7E @+
@OldOwner as NVARCHAR(128), er.CDKD%L
@NewOwner as NVARCHAR(128) 0'r%,0
AS U5]pi+r
DECLARE @Name as NVARCHAR(128) gBf4's
DECLARE @Owner as NVARCHAR(128) [,aqQ6S
DECLARE @OwnerName as NVARCHAR(128) 3<?XTv-
DECLARE curObject CURSOR FOR lI/0:|l
select 'Name' = name, nCKbgM'"
'Owner' = user_name(uid) 9 F^;!
from sysobjects H\GkW6
where user_name(uid)=@OldOwner TFepxF
order by name =q"eU=9
OPEN curObject Sc]P<F7N]
FETCH NEXT FROM curObject INTO @Name, @Owner oR*=|B
WHILE(@@FETCH_STATUS=0) ./p|?pu
BEGIN !%Y~~'5 h
if @Owner=@OldOwner K+T.o6+
begin xc?}TPpt
set @OwnerName = @OldOwner + '.' + rtrim(@Name) s(_+!d6
exec sp_changeobjectowner @OwnerName, @NewOwner w^1Fi8+
end ba3-t;S
-- select @name,@NewOwner,@OldOwner 4q$H
FETCH NEXT FROM curObject INTO @Name, @Owner V5D`eX9
END h~7,`fo
close curObject #'hLb
deallocate curObject r
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GO o/,NG U
10、SQL SERVER中直接循环写入数据 > 4oY 3wk8
declare @i int M_``'gw
set @i=1 { ?{U,&
while @i<30 -n*;W9
begin 'xFYUU]#T^
insert into test (userid) values(@i) -s$<Op{s
set @i=@i+1
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end T[Pa/j{
小记存储过程中经常用到的本周,本月,本年函数 s{/qS3=
Dateadd(wk,datediff(wk,0,getdate()),-1) :o"8MZp
Dateadd(wk,datediff(wk,0,getdate()),6) dZGbC 9
Dateadd(mm,datediff(mm,0,getdate()),0) CDp8)=WJFF
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^t[HoFRa
Dateadd(yy,datediff(yy,0,getdate()),0) mh;X~.98
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) N*DhjEU)[
上面的SQL代码只是一个时间段 +ySY>`1k~
Dateadd(wk,datediff(wk,0,getdate()),-1) yoqa@ V
Dateadd(wk,datediff(wk,0,getdate()),6) ODf4+& u
就是表示本周时间段. *(cU]NUH_
下面的SQL的条件部分,就是查询时间段在本周范围内的: YYRT.U'
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) s%;<O:x8o
而在存储过程中 :G)<}j"sM
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 83.E0@$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) oJ78jGTnb