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。 ?{Xp'D\z
;Xidv9c
d{!zJ+n
一、基础 -GgV&%'a
1、说明:创建数据库 oi3Ix7
CREATE DATABASE database-name P)TeF1~T
2、说明:删除数据库 ?fs#K;w
drop database dbname #tPy0QH
3、说明:备份sql server XSZjuQ<[3
--- 创建 备份数据的 device :\#]uDT2=
USE master VyU!r*
o
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' r'}#usB(
--- 开始 备份 \@2sI
BACKUP DATABASE pubs TO testBack .hvn/5s
4、说明:创建新表 /9y'UKl7[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QL(}k)dB
根据已有的表创建新表: `).;W
A:create table tab_new like tab_old (使用旧表创建新表) 0txSF^x
B:create table tab_new as select col1,col2... from tab_old definition only >fR#U"KPAB
5、说明:删除新表 (K"t</]
drop table tabname Q6Zh%\+h(
6、说明:增加一个列 Sdmynuv
U
Alter table tabname add column col type RDG,f/L2
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。 I@a7!ugU65
7、说明:添加主键: Alter table tabname add primary key(col) XeBSHvO_
说明:删除主键: Alter table tabname drop primary key(col) ;LT#/t)}<
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q~*3Z4)j
删除索引:drop index idxname U|h@Pw z
注:索引是不可更改的,想更改必须删除重新建。 C vTgtZ
'
9、说明:创建视图:create view viewname as select statement yC=vTzzp
删除视图:drop view viewname 7L:R&W6
10、说明:几个简单的基本的sql语句
qf]OSd
选择:select * from table1 where 范围 `|JQ)!Agx
插入:insert into table1(field1,field2) values(value1,value2) Y@%6*uTLa
删除:delete from table1 where 范围 m4P=,=%
更新:update table1 set field1=value1 where 范围 Df/f&;`
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Vo2frWF$
排序:select * from table1 order by field1,field2 [desc] r3 {o_w
总数:select count as totalcount from table1 ]*;+ U6/?
求和:select sum(field1) as sumvalue from table1 "=!QSb
平均:select avg(field1) as avgvalue from table1 w1A&p
最大:select max(field1) as maxvalue from table1 ]O&A:Us
最小:select min(field1) as minvalue from table1 Ip0@Q}^
;v+CQx
OEGAwP?F
oB Bdk@
11、说明:几个高级查询运算词 ELNA-ZKp
WU,72g=
Zr2QeLQC(
A: UNION 运算符 FkECY
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。 B
9]sSx
B: EXCEPT 运算符 !r!Mq~X<=
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。 7!N5uR
C: INTERSECT 运算符 uJp}9B60_
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。 g9"_ BG
注:使用运算词的几个查询结果行必须是一致的。 1y8:tri>N
12、说明:使用外连接 7#|NQ=yd
A、left outer join: Sdt2D
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。 &FvNz
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 lB\j>.c
B:right outer join: Y.*lO
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。 Q}Vho.N@=
C:full outer join: !%M-w0vC9
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。 1aMBCh<}JN
|QgXSe7
;%z0iZmg
二、提升 0Rk'sEX,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5BCaE)J
法一:select * into b from a where 1<>1 'Jl.fN
法二:select top 0 * into b from a s3kEux^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) gZ!(&u
insert into b(a, b, c) select d,e,f from b; +`Bn]e8O
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) n_ez6{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |~CnELF)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ng<`2XgU
4、说明:子查询(表名1:a 表名2:b) tw3d>H`
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) 'IW+"o
5、说明:显示文章、提交人和最后回复时间 kWz%v
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b rqh,BkQ0t
6、说明:外连接查询(表名1:a 表名2:b) 1k%ko?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Yh%wf3
UEO
7、说明:在线视图查询(表名1:a ) Tk2kis(n
select * from (SELECT a,b,c FROM a) T where t.a > 1; g4$%)0x%
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 Zz&i0r
select * from table1 where time between time1 and time2 &s;%(c04A
select a,b,c, from table1 where a not between 数值1 and 数值2
pn7 :")Zx
9、说明:in 的使用方法 < 5_Ys
select * from table1 where a [not] in ('值1','值2','值4','值6') 9FLn7Y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 gX _BJ6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) J+|ohA
11、说明:四表联查问题: f8^58]wx0
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 ..... @>:07]Dxo
12、说明:日程安排提前五分钟提醒 imhq*f#A[
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 /#se>4]
13、说明:一条sql 语句搞定数据库分页 /[IQ:':^
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 l{a&Zy)
14、说明:前10条记录 \mu9ikZ<
select top 10 * form table1 where 范围 ,]{NZ9
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.) 7~Ga>BK
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) yl ;'Ru:
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 ,"VQ0Z1
(select a from tableA ) except (select a from tableB) except (select a from tableC) q
|^O
17、说明:随机取出10条数据 2M#CJ&
select top 10 * from tablename order by newid() 1DcarF
18、说明:随机选择记录 ZAH<!@qh
select newid() U?lu@5 ^Z
19、说明:删除重复记录 O]g+z$2o
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -9*WQU9R
20、说明:列出数据库里所有的表名 eztk$o
select name from sysobjects where type='U' B;~agr
21、说明:列出表里的所有的 _Lb& 2PAG
select name from syscolumns where id=object_id('TableName') *pD;AU
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。 `^_:
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 @Kr)$F
显示结果: D)sEAfvX
type vender pcs `s_TY%&_}g
电脑 A 1 QMxz@HGa|
电脑 A 1 ~+C#c,Nw
光盘 B 2 uRy6~'
光盘 A 2 |)-:w?
手机 B 3 UQcmHZ+lf
手机 C 3 LG|,g3&
23、说明:初始化表table1 c6m,oS^
TRUNCATE TABLE table1 ;MJ1Q
24、说明:选择从10到15的记录 JAz;_wS(k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc -N(MEzAE
5l}h8So4
*n'xS L
Madaxx
三、技巧 R,bcE4WR"
1、1=1,1=2的使用,在SQL语句组合时用的较多 7:<Ed"rdE
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Mv=cLG?X
如:
'X,V
if @strWhere !='' E}=,"i
begin 8 vw]u_e
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Xt84 Evo
end KxwLKaImI
else n_Y]iAoc`
begin (Qm;]?/
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' VC(|t} L4
end sEN@q
我们可以直接写成 0cUt"(]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ~m?~eJK#a
2、收缩数据库 K-u/q6ufK
--重建索引 B,Brmn
DBCC REINDEX ?$c
DBCC INDEXDEFRAG 5UjQLB
--收缩数据和日志 WCu%@hh=h
DBCC SHRINKDB ,GnU]f
DBCC SHRINKFILE z0[ZO1Fo(
3、压缩数据库 g:M7/- "
dbcc shrinkdatabase(dbname) b]#d04]
4、转移数据库给新用户以已存在用户权限 !S-U8KI|
exec sp_change_users_login 'update_one','newname','oldname' F8Wq&X#r
go 1[`<JCFClc
5、检查备份集 c7IR06E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .A/H+.H;
6、修复数据库 q)b?X
^
ALTER DATABASE [dvbbs] SET SINGLE_USER |=T<WU1$
GO [9_ (+E[}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Gnt!!1_8L
GO
]:fCyIE
ALTER DATABASE [dvbbs] SET MULTI_USER & }}WP:U
GO :Qo
7、日志清除 30E v"
SET NOCOUNT ON 34Khg
DECLARE @LogicalFileName sysname, 8k^y.B
@MaxMinutes INT, V9_HC f
@NewSize INT c.Z4f7
USE tablename -- 要操作的数据库名 S\;.nAR
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -$t,}3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. So.P @CCd
@NewSize = 1 -- 你想设定的日志文件的大小(M) 8G] m7Z
-- Setup / initialize TeCpT2!5j
DECLARE @OriginalSize int p3FnYz-V
SELECT @OriginalSize = size ;OU>AnWr(&
FROM sysfiles :yjK*"T|OD
WHERE name = @LogicalFileName .4FcZJvy
SELECT 'Original Size of ' + db_name() + ' LOG is ' + M2Fj)w2
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _I-VWDCk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \nAHpF
FROM sysfiles 2U`W[
WHERE name = @LogicalFileName Y*cJ4hQ
CREATE TABLE DummyTrans >-5Gt
(DummyColumn char (8000) not null) 65#:2,s
DECLARE @Counter INT, ?VP!1O=J
@StartTime DATETIME, /
&D$kxz
@TruncLog VARCHAR(255) g^ $11
SELECT @StartTime = GETDATE(), 33'lZubV
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]j2v"n
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Pph8"`mv.m
EXEC (@TruncLog) i6#]$ B
-- Wrap the log if necessary. zZ"U9!T
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired )]c3bMVE-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) s[2ZxCrCw
AND (@OriginalSize * 8 /1024) > @NewSize Evq Ai/(g
BEGIN -- Outer loop. )QCM2
SELECT @Counter = 0 !FO^:V<|5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "=\_++
BEGIN -- update 6mpg&'>
INSERT DummyTrans VALUES ('Fill Log') oXlxPN39
DELETE DummyTrans _c
]3nzIr
SELECT @Counter = @Counter + 1 fCf#zV[
END K}E7|gdG
EXEC (@TruncLog) h<'5q&y
END Oqpl2Y"/
SELECT 'Final Size of ' + db_name() + ' LOG is ' + R =9~*9
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + u@_!mjXQ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {_XrZ(y/
FROM sysfiles o;4e)tK
WHERE name = @LogicalFileName BT#=Xh
DROP TABLE DummyTrans k3>ur>aW
SET NOCOUNT OFF }#HTO:r
8、说明:更改某个表 +}1hU
:qW
exec sp_changeobjectowner 'tablename','dbo' ) Zb`~w
9、存储更改全部表 f./m7TZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =6Sj}/
@OldOwner as NVARCHAR(128), Wd`
QpW
@NewOwner as NVARCHAR(128) CnSX
AS s'aV q B
DECLARE @Name as NVARCHAR(128) q bZ,K@0
DECLARE @Owner as NVARCHAR(128) ?(/j<,m^
DECLARE @OwnerName as NVARCHAR(128) EhIV(q9x
DECLARE curObject CURSOR FOR seuN,jpt
select 'Name' = name, ]a6O(]
'Owner' = user_name(uid) Ly)(_Tp@+
from sysobjects SQt|(r)
where user_name(uid)=@OldOwner wL-ydMIx
order by name 7}'A)C>J;
OPEN curObject o d}EM_
FETCH NEXT FROM curObject INTO @Name, @Owner 33<fN:J]f
WHILE(@@FETCH_STATUS=0) `!omzE*bk5
BEGIN {nQ)4.e6
if @Owner=@OldOwner qH
h'l;.
begin 0i*'N ch#i
set @OwnerName = @OldOwner + '.' + rtrim(@Name) wHOlj)CZ
exec sp_changeobjectowner @OwnerName, @NewOwner o\]:!#r{T
end tSb?]J
-- select @name,@NewOwner,@OldOwner 88#qu.
FETCH NEXT FROM curObject INTO @Name, @Owner UROj9COv
END ?H[5O+P[
close curObject 8{G?92
{rN
deallocate curObject Q\27\2
GO C^/ -lc
10、SQL SERVER中直接循环写入数据 1J-Qh<Q
declare @i int C'-zh\a
set @i=1 L`jB)wF/J
while @i<30 aI={,\
begin $K?T=a;z
insert into test (userid) values(@i) S~k 0@
set @i=@i+1 %9QMzz5
end #5y9L
小记存储过程中经常用到的本周,本月,本年函数 {}g %"mi#
Dateadd(wk,datediff(wk,0,getdate()),-1) Z(Eke
Dateadd(wk,datediff(wk,0,getdate()),6) jB%"AvIX
Dateadd(mm,datediff(mm,0,getdate()),0) $AA~]'O>6:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) my\o P(e\
Dateadd(yy,datediff(yy,0,getdate()),0) oI_oz0nHk
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -v;n"Zy1
上面的SQL代码只是一个时间段 aJ6#=G61l
Dateadd(wk,datediff(wk,0,getdate()),-1) s-C!uq
Dateadd(wk,datediff(wk,0,getdate()),6) kUn2RZ6$#
就是表示本周时间段. llHc=&y#
下面的SQL的条件部分,就是查询时间段在本周范围内的: .Na&I)udX.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) }iua]
4|
而在存储过程中 9u?)vR[@e
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }z%OnP
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =de<WoKnu2