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。 k"$V O+}m
cO9Aw !
TH &B9
一、基础 g~b'}^J
1、说明:创建数据库 tHeLq*))
CREATE DATABASE database-name 7&1: ]{_
2、说明:删除数据库 5JXLfYTUI
drop database dbname (WvA9s{/
3、说明:备份sql server aT #|mk=\
--- 创建 备份数据的 device 0M?}S~p]
USE master ><~hOK?v
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' I5]zOKlVR
--- 开始 备份 w0iEx1i
BACKUP DATABASE pubs TO testBack rB]/N,R
4、说明:创建新表 u.6%n.g
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) FReK
根据已有的表创建新表: T*m_rDDt
A:create table tab_new like tab_old (使用旧表创建新表) da@
.J9
B:create table tab_new as select col1,col2... from tab_old definition only v#xF;@G
5、说明:删除新表 om6R/K
drop table tabname , fn=%tiUk
6、说明:增加一个列 }=gGs
Alter table tabname add column col type <*P1Sd.
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 O/Vue
7、说明:添加主键: Alter table tabname add primary key(col) g,nE iL
说明:删除主键: Alter table tabname drop primary key(col) XJ9>a-{
8、说明:创建索引:create [unique] index idxname on tabname(col....) 2Z~ofrj
删除索引:drop index idxname 6%-2G@6d
注:索引是不可更改的,想更改必须删除重新建。 ,")7uMZaF\
9、说明:创建视图:create view viewname as select statement g=Lt2UIJ
删除视图:drop view viewname ]Ea-?IhD
10、说明:几个简单的基本的sql语句 OgX."pK
选择:select * from table1 where 范围 ||f4f3R'
插入:insert into table1(field1,field2) values(value1,value2) 4.TG&IQ
nN
删除:delete from table1 where 范围 U' Cp3>
更新:update table1 set field1=value1 where 范围 DNPK1e3a{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! <3KrhhH
排序:select * from table1 order by field1,field2 [desc] ;<\*(rUe
总数:select count as totalcount from table1 @Klj!2cv$
求和:select sum(field1) as sumvalue from table1 mwxJ#
平均:select avg(field1) as avgvalue from table1 N<x5:f#+
最大:select max(field1) as maxvalue from table1 dq2v[?*R
最小:select min(field1) as minvalue from table1 c1[;a>
SW7%SX,xM
.kVga+la?
) =[Tgh
11、说明:几个高级查询运算词 0U'r ia:$
<,{v>vlw
R[QE:#hT
A: UNION 运算符 C;` fOCz^
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。 jolCR-FDu
B: EXCEPT 运算符 <Vim\
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。 ]+AI:
C: INTERSECT 运算符 $1e@3mzM
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 H\T
h4teE
注:使用运算词的几个查询结果行必须是一致的。 `8I&(k<wLe
12、说明:使用外连接 @OpcS>:R
A、left outer join: ;
OsN^
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Hi Yx(hY
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c %}/)_RzQ
B:right outer join: 4J s>yP
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 r"+
WUU
C:full outer join: kcle|B
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ;1KhUf;&F
t%)L8%Jr
vzL>ZBeZ
二、提升 kQ +
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ]zO]*d=m
法一:select * into b from a where 1<>1 g!$
"CX%8
法二:select top 0 * into b from a a
<3oyY'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^P[*yf
insert into b(a, b, c) select d,e,f from b; UxW~yk
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) 7?Fl [FW$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 QO8/?^d
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. v [x`I;
4、说明:子查询(表名1:a 表名2:b) NoMC*",b>
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) 2}NfR8
N
5、说明:显示文章、提交人和最后回复时间 B~^\jRd"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ^JTfRZ:a
6、说明:外连接查询(表名1:a 表名2:b) 9} vWTt0
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@w&$M{tPF
7、说明:在线视图查询(表名1:a ) #\}hN~@F
select * from (SELECT a,b,c FROM a) T where t.a > 1; tQ/U'Ap&
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 er53?z7zP.
select * from table1 where time between time1 and time2 t/3veDh@
select a,b,c, from table1 where a not between 数值1 and 数值2 +"<f22cS1
9、说明:in 的使用方法 X@arUs7
select * from table1 where a [not] in ('值1','值2','值4','值6') ,GK>|gNsb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7Qo*u;fr
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]SQ_*$`
11、说明:四表联查问题: P5N"7/PfW
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 ..... DT*/2TH*l
12、说明:日程安排提前五分钟提醒 *
08LW|:,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 r
)T`?y
13、说明:一条sql 语句搞定数据库分页 t*COzE
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 :7R\"@V4
14、说明:前10条记录 zmdOL9"a
select top 10 * form table1 where 范围 ? f%@8%px
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.) (k[<>$hL*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) rTi.k
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ag3T[}L
z
(select a from tableA ) except (select a from tableB) except (select a from tableC) 9U+^8,5
17、说明:随机取出10条数据 3LEN~N}
select top 10 * from tablename order by newid() DU;]Q:r{
18、说明:随机选择记录 A)qOJ(OEz
select newid() ^0r@",
19、说明:删除重复记录 e@6}?q;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &P\T{d2"
20、说明:列出数据库里所有的表名 YXmLd'F^3
select name from sysobjects where type='U' f`?|A
21、说明:列出表里的所有的 P?bdjU#_n`
select name from syscolumns where id=object_id('TableName') 5f1yszd
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 zP5H TEz
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type m8FKr/Z-
显示结果: o}[wu:>yk
type vender pcs 1f}Dza9
电脑 A 1 77)C`]0(
电脑 A 1 jildiT[s
光盘 B 2 Ngg (<ZN
光盘 A 2 Q 5Ln'La$
手机 B 3 d~.#K S
手机 C 3 A>X#[qx
23、说明:初始化表table1 EB)0 iQ
TRUNCATE TABLE table1 p}C3<[Nk
24、说明:选择从10到15的记录 5^%FEZ&Sp
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc `/0FXb
8h
tf>?;
](%-5G1<
r1,RloyZS
三、技巧 ,#s}nJ4
1、1=1,1=2的使用,在SQL语句组合时用的较多 9X!OQxmg
"where 1=1" 是表示选择全部 "where 1=2"全部不选, J H6\;G6
如: P,,@&*
:
if @strWhere !='' d=q2Or
begin eQMY3/#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W4Zi?@L>'
end c: _l+CgeH
else {uq
begin T@X!vCjf6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qg+8i9Y!
end SV-pS>#
我们可以直接写成 *r[PZ{D+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;X\,-pjv
2、收缩数据库 *ozeoX'5D
--重建索引 ZVeY`o(uE
DBCC REINDEX 4SmhtC
DBCC INDEXDEFRAG C]{43
--收缩数据和日志 ptX;-'j(
DBCC SHRINKDB >i=mw5`D]
DBCC SHRINKFILE ,b2Cl[
3、压缩数据库 FLi)EgZXt
dbcc shrinkdatabase(dbname) M,NYF`;a
4、转移数据库给新用户以已存在用户权限 ZE4~rq/W
exec sp_change_users_login 'update_one','newname','oldname' EFV'hMjS)
go i:@00)V{,
5、检查备份集 {]`O $S
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' K
o,O!T.
6、修复数据库 X5=Dc+
ALTER DATABASE [dvbbs] SET SINGLE_USER {5:y,=Y
GO Qb/qUUQO;0
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK YMC*<wXN
GO |]^OX$d
ALTER DATABASE [dvbbs] SET MULTI_USER 0z.Hl1
GO EZao\,t
7、日志清除 CsXIq.9
SET NOCOUNT ON /z`LB
DECLARE @LogicalFileName sysname, UZ v^3_,qz
@MaxMinutes INT, IrJCZsk
@NewSize INT M~=9ym
USE tablename -- 要操作的数据库名 :4/RB%)"
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [.dF)I3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. mm'Pe4*
@NewSize = 1 -- 你想设定的日志文件的大小(M) ux'!1mN
-- Setup / initialize r:<UV^; 9l
DECLARE @OriginalSize int X&pK#=
SELECT @OriginalSize = size pGzzv{H
FROM sysfiles !Mceg
WHERE name = @LogicalFileName fC52nK&T8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3
rV)JA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #D&eov?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =rGjOb3+
FROM sysfiles vEk
jd#
WHERE name = @LogicalFileName g&) XaF[!
CREATE TABLE DummyTrans G)G5eXXX
(DummyColumn char (8000) not null)
?x=;?7
DECLARE @Counter INT, LDx1@a|83
@StartTime DATETIME, +.:- :
@TruncLog VARCHAR(255) &V:iy
SELECT @StartTime = GETDATE(), gYw4YP0Gz
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' z`y!C3w<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ilHZx2k
EXEC (@TruncLog) iO~3rWQ
-- Wrap the log if necessary. JT#jJ/^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {rBS52,Z#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p~6/
AND (@OriginalSize * 8 /1024) > @NewSize { owK~
BEGIN -- Outer loop. fKb8)PDP
SELECT @Counter = 0 Z`Rrv$M!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Nyip]VwMJ
BEGIN -- update uPQ:}zL2
INSERT DummyTrans VALUES ('Fill Log') ^giseWR(
DELETE DummyTrans '1_CMr
SELECT @Counter = @Counter + 1 $OldHe[p
END gDa}8!+i
EXEC (@TruncLog) by (xv0v;
END ,C1}gPQ6<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + |>Qj]
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1/:WA:]1,
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ozy~`$;c
FROM sysfiles &A)AV<=>T
WHERE name = @LogicalFileName fucG 9B
DROP TABLE DummyTrans Q30AaG}f
SET NOCOUNT OFF ~7IXJeon
8、说明:更改某个表 "AMbU68
exec sp_changeobjectowner 'tablename','dbo' |
U )
9、存储更改全部表 3A!`U6C(
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch YzNSZJPD
@OldOwner as NVARCHAR(128), Btp 9v<"
@NewOwner as NVARCHAR(128) JvX]^t/}
AS .zZee,kM
DECLARE @Name as NVARCHAR(128) 9`4M o+
DECLARE @Owner as NVARCHAR(128) U@T"teGBA
DECLARE @OwnerName as NVARCHAR(128) i=jwk_y
DECLARE curObject CURSOR FOR V{+'(<SV
select 'Name' = name, pyJY]"UHVE
'Owner' = user_name(uid) E<]O,z;F
from sysobjects agp`<1h9
where user_name(uid)=@OldOwner GH[ATL
order by name xkV(E!O
OPEN curObject x ]{}y_
FETCH NEXT FROM curObject INTO @Name, @Owner z3x/Y/X$S
WHILE(@@FETCH_STATUS=0) G<:_O-cPSv
BEGIN GCm(3%{V%(
if @Owner=@OldOwner 5+Fr/C
begin H3CG'?{ _
set @OwnerName = @OldOwner + '.' + rtrim(@Name) yq]= +X>(
exec sp_changeobjectowner @OwnerName, @NewOwner |mvY=t
%
end KcKdhqdN-
-- select @name,@NewOwner,@OldOwner /enlkZx=8
FETCH NEXT FROM curObject INTO @Name, @Owner !Lkk1zo
END m[n=t5~
close curObject g9C/Oj`I
deallocate curObject 2t
7':X
GO XT+V> HI
10、SQL SERVER中直接循环写入数据 89hV{^
declare @i int i7D[5!
set @i=1 wr>[Eo@%\
while @i<30 AH-B/c5
begin S\5%nz\
insert into test (userid) values(@i) t$~CLq5ad
set @i=@i+1 NhJ]X cfP8
end rMr:\M]t
小记存储过程中经常用到的本周,本月,本年函数 j}u b
Dateadd(wk,datediff(wk,0,getdate()),-1) I(m*%>
Dateadd(wk,datediff(wk,0,getdate()),6) *WMI<w~_
Dateadd(mm,datediff(mm,0,getdate()),0) bji5X')~#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =`<9N%
Dateadd(yy,datediff(yy,0,getdate()),0) Jj%"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) hvW FzT5
上面的SQL代码只是一个时间段 lEAf\T7
Dateadd(wk,datediff(wk,0,getdate()),-1) # `L?24%
Dateadd(wk,datediff(wk,0,getdate()),6) Ck1{\=t
就是表示本周时间段. iepolO=
下面的SQL的条件部分,就是查询时间段在本周范围内的: k0r93xa
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +q*WY*gX
而在存储过程中 f[1 s4Dp3-
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 9!} ?}`'_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) YOOcHo.F