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。 2EfF=Fm>
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一、基础 av$/Om:
1、说明:创建数据库 h3Q21D'f
CREATE DATABASE database-name DXa-rk8
2、说明:删除数据库 ~R&;v3
drop database dbname #_(jS+lP?k
3、说明:备份sql server 5JLu2P
--- 创建 备份数据的 device #:^YI
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USE master -$WYj"
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' k5C@>J
--- 开始 备份 Fm #w2o
BACKUP DATABASE pubs TO testBack JM\m)RH0
4、说明:创建新表 r%.do;5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sRrzp=D
根据已有的表创建新表: 9M1d%jT
A:create table tab_new like tab_old (使用旧表创建新表) "sl1vzRN
B:create table tab_new as select col1,col2... from tab_old definition only 7g(F#T?;'
5、说明:删除新表 o4zM)\;F
drop table tabname H)>;/#!r-
6、说明:增加一个列 sH?/E6
Alter table tabname add column col type FN%m0"/Z{t
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。 >B2q+tA
7、说明:添加主键: Alter table tabname add primary key(col) CJXg@\\/
说明:删除主键: Alter table tabname drop primary key(col) 2w-51tqm
8、说明:创建索引:create [unique] index idxname on tabname(col....) Hx\H $Y
删除索引:drop index idxname h<SQL97N
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement y;AL'vm9
删除视图:drop view viewname H03jDM8Q
10、说明:几个简单的基本的sql语句 &ZX{R#[L
选择:select * from table1 where 范围 %B)6$!x
插入:insert into table1(field1,field2) values(value1,value2) IrWD%/$H
删除:delete from table1 where 范围 S -'fS2
更新:update table1 set field1=value1 where 范围 qq1 - DG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! mBG=jI "xh
排序:select * from table1 order by field1,field2 [desc] d GFGr}&s
总数:select count as totalcount from table1 #~.w&~:
求和:select sum(field1) as sumvalue from table1 !Wy[).ZAf
平均:select avg(field1) as avgvalue from table1 O=dJi9;`#_
最大:select max(field1) as maxvalue from table1 A6pjRxg
最小:select min(field1) as minvalue from table1 y:vxE8$Q
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11、说明:几个高级查询运算词 <@Fy5k-%.
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A: UNION 运算符 ~2zMkVH
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。 Z+StB15
B: EXCEPT 运算符 3:f[gV9K
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。 r@o6voX
C: INTERSECT 运算符 0`I-2M4F*Q
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。 Iy.rqc/86
注:使用运算词的几个查询结果行必须是一致的。 -pE(_
12、说明:使用外连接 pOrWg@<\L
A、left outer join: "/nNM{^
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。 !E-Pa5s
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 3^Q]j^e4Ny
B:right outer join: ^+1#[E
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。 Q26qNn
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C:full outer join: LT,? $I
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 F1Hh7
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二、提升 PT5AA8F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G_dsrpI=N
法一:select * into b from a where 1<>1 wprX!)w<i
法二:select top 0 * into b from a }irn'`I
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bC3 F
insert into b(a, b, c) select d,e,f from b; 4ON_$FUe
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) _ %x4ty
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 i]#+1Hf
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. X2xuwA
4、说明:子查询(表名1:a 表名2:b) R3!@?mcr
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) ?*oKX
5、说明:显示文章、提交人和最后回复时间 J-<^P5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b BkZV!Eg
6、说明:外连接查询(表名1:a 表名2:b) d|*"IFe
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c wV)}a5+
7、说明:在线视图查询(表名1:a ) \xUe/=
select * from (SELECT a,b,c FROM a) T where t.a > 1; !!:LJ
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 wHem5E
select * from table1 where time between time1 and time2 c. A|Ir
select a,b,c, from table1 where a not between 数值1 and 数值2 &BvZF
9、说明:in 的使用方法 [*Z`Kc
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 IB`>'~s&A
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /2m?15c+
11、说明:四表联查问题: Hku!bJ
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 ..... fbkd "7u
12、说明:日程安排提前五分钟提醒 N<L`c/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 2PR^:h2
13、说明:一条sql 语句搞定数据库分页 ;=< ^0hxer
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 vw)7 !/#
14、说明:前10条记录 u?[ q=0.J7
select top 10 * form table1 where 范围 7E @+
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.) 4A3nO<oMF
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) kpI{KISQu
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 \M"UmSB o
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4W#E`9
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17、说明:随机取出10条数据 D)brPMS:o
select top 10 * from tablename order by newid() m"9XT)N
18、说明:随机选择记录 WpLZQ6wH
select newid() [,aqQ6S
19、说明:删除重复记录 JNFIT;L
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) BvU"4d;x
20、说明:列出数据库里所有的表名 j2Pn<0U
select name from sysobjects where type='U' Zh/Uu6
21、说明:列出表里的所有的 e62Dx#IY
select name from syscolumns where id=object_id('TableName') k5&bq2)I
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。 \Yoa:|%*y
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 sIl33kmv
显示结果: |Cdvfk
type vender pcs Kwhdu<6
电脑 A 1 {R^'=(YFy
电脑 A 1 sgr=w+",Q
光盘 B 2 %ObD2)s6:^
光盘 A 2 3[XQR8o
手机 B 3 h)v^q: ='
手机 C 3 M-
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23、说明:初始化表table1 )=Q)BN[
TRUNCATE TABLE table1 +}
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24、说明:选择从10到15的记录 S
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Fn^C{p^
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三、技巧 [ "xn5lE
1、1=1,1=2的使用,在SQL语句组合时用的较多 = zl=SLe
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?R5'#|EyX
如: ? &zQaxD
if @strWhere !='' T#O??3/%$1
begin jvVi%k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b8f+,2Tk
end htPqT,L
else ^I]{7$6^
begin L"<B;u5pM
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' f'6|OsVQ
end 5v^L9!`@%v
我们可以直接写成 qXXGF_Q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere zEw>SP1,
2、收缩数据库 2>\\@1
--重建索引 ,eQ[Fi!!
DBCC REINDEX :ZxLJK9x1
DBCC INDEXDEFRAG 'xFYUU]#T^
--收缩数据和日志 -s$<Op{s
DBCC SHRINKDB
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DBCC SHRINKFILE T[Pa/j{
3、压缩数据库 s{/qS3=
dbcc shrinkdatabase(dbname) :o"8MZp
4、转移数据库给新用户以已存在用户权限 dZGbC 9
exec sp_change_users_login 'update_one','newname','oldname' CDp8)=WJFF
go ^t[HoFRa
5、检查备份集 +dkS/b
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?G?gy2
6、修复数据库 !6w{(Rc(C
ALTER DATABASE [dvbbs] SET SINGLE_USER 0W>9'Rw
GO MjaUdfx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK D*vm
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GO Pj7gGf6v
ALTER DATABASE [dvbbs] SET MULTI_USER CQODXB^
GO FyG6!t%
7、日志清除 0>!/rR7
SET NOCOUNT ON WP-jtZ?!"
DECLARE @LogicalFileName sysname, A6ewdT?>,
@MaxMinutes INT, Qrz4}0
@NewSize INT #X.+
USE tablename -- 要操作的数据库名 ~DLIz g7p!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 'Zk<l#"}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. eSl-9
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@NewSize = 1 -- 你想设定的日志文件的大小(M) #Nte^E4
-- Setup / initialize 4x'AC%&Qi
DECLARE @OriginalSize int jnoL2JR[=-
SELECT @OriginalSize = size bO49GEUT _
FROM sysfiles 0zqj0
WHERE name = @LogicalFileName &WZP2Q|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MY-.t-3
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + a%hGZCI
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >Csbjf6
FROM sysfiles ^Y^"'"
WHERE name = @LogicalFileName c!&Qj
CREATE TABLE DummyTrans s0{
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(DummyColumn char (8000) not null) !W1eUY
DECLARE @Counter INT, GH'O!}
@StartTime DATETIME, {TZE/A3D,
@TruncLog VARCHAR(255) u9![6$R
SELECT @StartTime = GETDATE(), Y~oT)wTU
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Rq7p29w
DBCC SHRINKFILE (@LogicalFileName, @NewSize) W81o"TR|pt
EXEC (@TruncLog) .R5/8VuHF
-- Wrap the log if necessary. NcL
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired lVeH+"M?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~SVQ;U)-
AND (@OriginalSize * 8 /1024) > @NewSize /aUFc '5
BEGIN -- Outer loop. Z|^MGyn
SELECT @Counter = 0 CKTrZxR"
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,VD6s!(
BEGIN -- update <<3+g"enno
INSERT DummyTrans VALUES ('Fill Log') 2ALj}
DELETE DummyTrans 7o{*Z
SELECT @Counter = @Counter + 1 "@/ba!L+
END ]Sta]}VQ
EXEC (@TruncLog) p[YWSjf
END wL<j:>Ke[3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PO
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + a'[)9:
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' X9'xn 0n;
FROM sysfiles X*Z5 P
WHERE name = @LogicalFileName 1<uwU(
DROP TABLE DummyTrans ]+IVSxa!u
SET NOCOUNT OFF 0&`}EXe<f
8、说明:更改某个表 #t5juX9Ho9
exec sp_changeobjectowner 'tablename','dbo' xbC~C~#
9、存储更改全部表 IYNMU\s
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch MOV =n75
@OldOwner as NVARCHAR(128), >.Q0Tx!P
@NewOwner as NVARCHAR(128) ?~qC,N [
AS rh $1-Y
DECLARE @Name as NVARCHAR(128) 6=>7M
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DECLARE @Owner as NVARCHAR(128) k.Zll,s
DECLARE @OwnerName as NVARCHAR(128) ?"@ET9
DECLARE curObject CURSOR FOR }%{=].)L
select 'Name' = name, (G5T%[/U
'Owner' = user_name(uid) vug-n 8
from sysobjects ~yN(-I1P
where user_name(uid)=@OldOwner ChIoR:y>
order by name e<'U8|}hc{
OPEN curObject yQS04Bl]
FETCH NEXT FROM curObject INTO @Name, @Owner =mJF_Ri
WHILE(@@FETCH_STATUS=0) DS
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BEGIN #v qz{R~nM
if @Owner=@OldOwner uAb 03Q
begin A;%kl`~iyz
set @OwnerName = @OldOwner + '.' + rtrim(@Name) oWcACs3fB
exec sp_changeobjectowner @OwnerName, @NewOwner yGV{^?yoP
end X'2Gi
-- select @name,@NewOwner,@OldOwner JfKg_&hM
FETCH NEXT FROM curObject INTO @Name, @Owner jI#z/a!j:
END bD@@tGr;W
close curObject Orc>.~+f%A
deallocate curObject
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GO A}eOR=E
10、SQL SERVER中直接循环写入数据 W}k[slqZA
declare @i int ~\bHfiIDy
set @i=1 Fhi5LhWe+.
while @i<30 `Y\QUj
begin 1OPfRDn.bk
insert into test (userid) values(@i) 8g5.7{ky
set @i=@i+1 !'PlDGD
end QAXYrRu
小记存储过程中经常用到的本周,本月,本年函数 7+S44)w}~
Dateadd(wk,datediff(wk,0,getdate()),-1) Lnx2xoNk
Dateadd(wk,datediff(wk,0,getdate()),6) 2^bgC~2C1
Dateadd(mm,datediff(mm,0,getdate()),0) ./!KE"!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^=#!D[xj>
Dateadd(yy,datediff(yy,0,getdate()),0) *C/KM;&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5|m9:Hv[#
上面的SQL代码只是一个时间段 J]]\&MtaO
Dateadd(wk,datediff(wk,0,getdate()),-1) %9YA^ri
Dateadd(wk,datediff(wk,0,getdate()),6) (lWKy9eTy`
就是表示本周时间段. ;Yu>82o.:
下面的SQL的条件部分,就是查询时间段在本周范围内的: h~.V[o7=
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) C!kbZTO[p"
而在存储过程中 ]h!*T{:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ~6fRS2u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) cB36p&%