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。 Za01z^
+pjD{S~Y
,%ajIs"Gi
一、基础 9'4cqR
1、说明:创建数据库 f'%}{l: ss
CREATE DATABASE database-name {=R=\Y?r&
2、说明:删除数据库 wL%>
drop database dbname vO&1F@
3、说明:备份sql server +*|E%pq
--- 创建 备份数据的 device 1P[!B[;c
USE master ke/o11LP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' K, 35*
--- 开始 备份 >eU;lru2Q
BACKUP DATABASE pubs TO testBack K):)bL(B
4、说明:创建新表 ) I5f`r=Ry
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) W~7q&||;C
根据已有的表创建新表: isDr|g$S
A:create table tab_new like tab_old (使用旧表创建新表) i-/'F
B:create table tab_new as select col1,col2... from tab_old definition only #FeM.k6
5、说明:删除新表 f:HRrKf9
drop table tabname lual'~
6、说明:增加一个列 _e?(Gs0BM
Alter table tabname add column col type A>'o5+
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。 u/,m2N9cL
7、说明:添加主键: Alter table tabname add primary key(col) 46$5f?Z
说明:删除主键: Alter table tabname drop primary key(col) HF0J>Clq
8、说明:创建索引:create [unique] index idxname on tabname(col....) pG|DT ?
删除索引:drop index idxname oFY'Ek;d
注:索引是不可更改的,想更改必须删除重新建。 Xf Y]qQP
9、说明:创建视图:create view viewname as select statement y|1-,u.$
删除视图:drop view viewname ;%Z)$+Z_)<
10、说明:几个简单的基本的sql语句 3:76x
选择:select * from table1 where 范围 h],_1!0
插入:insert into table1(field1,field2) values(value1,value2) t/nu/yz5E
删除:delete from table1 where 范围 L]9*^al
更新:update table1 set field1=value1 where 范围 %40|7O
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 'Z;R!@Dm
排序:select * from table1 order by field1,field2 [desc] H'2pmwk
总数:select count as totalcount from table1 1k;X*r#
求和:select sum(field1) as sumvalue from table1 4S+P]U*jW
平均:select avg(field1) as avgvalue from table1 Thz&wH`W
最大:select max(field1) as maxvalue from table1 g9
g
&]
最小:select min(field1) as minvalue from table1 Nhuw8Xv
6R"& !.ZF
NO;+:0n
q?JP\_o:
11、说明:几个高级查询运算词 {:!*1L
ve'h z{W
7TlOF
A: UNION 运算符 2}hEBw68
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 O-q [#P
B: EXCEPT 运算符 _AK-AY
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 *\-6p0~A
C: INTERSECT 运算符 PYW~x@]k%,
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 !~PV\DQN
注:使用运算词的几个查询结果行必须是一致的。 n{=vP`V_
12、说明:使用外连接 kOeW,:&65
A、left outer join: PC=b.H8P+W
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 k${25*M!3
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 7oK!!Qd^w
B:right outer join: <08)G7
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。 }eSaF@.
C:full outer join: THkg,*;:
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。 =5',obYN>c
HZ )z^K?1
3hGYNlQ^
二、提升 "! m6U#^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
Jf9a<[CcV
法一:select * into b from a where 1<>1 q\/ph(HF
法二:select top 0 * into b from a X8"4)IZ3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ?s6v>#H%
insert into b(a, b, c) select d,e,f from b; ,F!zZNW9
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) #8i DM5:EQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 -QN1=G4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. lvY[E9I0
4、说明:子查询(表名1:a 表名2:b)
6g576
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) r roI
5、说明:显示文章、提交人和最后回复时间 ~l+2Z4nV
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b g1Ed:V]_
6、说明:外连接查询(表名1:a 表名2:b) [0qe ?aI
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c g]vo."}5E
7、说明:在线视图查询(表名1:a ) <A^sg?s<'
select * from (SELECT a,b,c FROM a) T where t.a > 1; I() =Ufs5z
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 OD]`oJ|
select * from table1 where time between time1 and time2 XXPn)kmWR
select a,b,c, from table1 where a not between 数值1 and 数值2 X|y(B%:
9、说明:in 的使用方法 . |%n"{
select * from table1 where a [not] in ('值1','值2','值4','值6') ~@ =(#tO.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Bs)'Gk`1
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )0+6^[Tqq
11、说明:四表联查问题: `,QcOkvbC
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 ..... 0xVw{k}1U
12、说明:日程安排提前五分钟提醒 V^Y'!w\LGI
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 o=J-Ju
13、说明:一条sql 语句搞定数据库分页 R!f<6l8#W
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 `OFW^Esc
14、说明:前10条记录 mC2K &'[
select top 10 * form table1 where 范围 /|q.q
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.) (qglD
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) V56WgOBxz
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 7UIf
(select a from tableA ) except (select a from tableB) except (select a from tableC) 0FSN IPx
17、说明:随机取出10条数据 E75/EQ5p]p
select top 10 * from tablename order by newid() *4/FN TC
18、说明:随机选择记录 Lq|>n[KY
select newid() ]Hp>~Zvbb
19、说明:删除重复记录 $Nd,6w*`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) sYjhQN=Y*
20、说明:列出数据库里所有的表名 H2H`7 +I,
select name from sysobjects where type='U' 27k(`{K
21、说明:列出表里的所有的 8EI9&L>
select name from syscolumns where id=object_id('TableName') o]EL=j
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 _f'v>"K
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type h PL]B_<
显示结果: e2f+Fv
9
type vender pcs q3AqU?f
电脑 A 1 Aa=:AkrH
电脑 A 1 [Ur\^wS
光盘 B 2 R&9FdM3K`:
光盘 A 2 ,DZvBS
手机 B 3 f(Y_<%
手机 C 3 3P9ux
23、说明:初始化表table1 t;BUZE_!0c
TRUNCATE TABLE table1 y~fKLIoz"
24、说明:选择从10到15的记录 fqhL"Ah
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (J[Xryub
Hs*["zFc
H T|DT
yL*]_
三、技巧 4q E95THB
1、1=1,1=2的使用,在SQL语句组合时用的较多 oQ 2$z8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r/2=
nE
如: &E_a0*)e
if @strWhere !='' CmZayV
begin U}LW8886
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &^r>Q`u
end ;$QC_l''b
else H_X^)\oJ
begin P(hGkY=(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `
y\)X
C7
end d'RvpoM
我们可以直接写成 eXW|{asx
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere q.c)>=!.
2、收缩数据库 r- <O'^C
--重建索引 $VuXr=f}
DBCC REINDEX /8FmPCp}r
DBCC INDEXDEFRAG +n)n6}S
--收缩数据和日志 )th[fUC(
DBCC SHRINKDB +!/ATR%Uci
DBCC SHRINKFILE %{@Q7
3、压缩数据库 -QrC>3xZR
dbcc shrinkdatabase(dbname) |_V(^b}
4、转移数据库给新用户以已存在用户权限 K:wI'N"N
exec sp_change_users_login 'update_one','newname','oldname' wDJ`#"5p{
go 5~L]zE
5、检查备份集 5% 2A[B
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Y{p$%
6、修复数据库 FACw;/rW
ALTER DATABASE [dvbbs] SET SINGLE_USER tAdE<).!
GO ^7-zwl(>?N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK #c^V%
GO :?>7Z6
ALTER DATABASE [dvbbs] SET MULTI_USER *l+#<5x
GO aD^$v
7、日志清除 @^P^-B
SET NOCOUNT ON [nTI\17iA
DECLARE @LogicalFileName sysname, KK){/I=z
@MaxMinutes INT, E
TT46%Y
@NewSize INT Mo,&h?VOM?
USE tablename -- 要操作的数据库名 .%zcm
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 CU'JvVe3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. t|aV:x
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2 !s&|lI
-- Setup / initialize }LzBo\
DECLARE @OriginalSize int f"ZlJV a
SELECT @OriginalSize = size RkF#NCnL;
FROM sysfiles p3I"LY
WHERE name = @LogicalFileName #b/qR^2qW
SELECT 'Original Size of ' + db_name() + ' LOG is ' + fB+L%+mr8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b)LT[>f
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 3S^0%"fY
FROM sysfiles =>jp\A
WHERE name = @LogicalFileName eqbN_$>
CREATE TABLE DummyTrans T(b9b,ov)
(DummyColumn char (8000) not null) @60D@Y
DECLARE @Counter INT,
Dw-d`8*
@StartTime DATETIME, {/'T:n#
@TruncLog VARCHAR(255) j4.wd
RK
SELECT @StartTime = GETDATE(), dbI>\khI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' A#{63_H
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7=!9kk 0
EXEC (@TruncLog) J K
k0f9)
-- Wrap the log if necessary. y.r N(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired )!T~l(g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -%nD'qy,.
AND (@OriginalSize * 8 /1024) > @NewSize
5)[~
T2j!
BEGIN -- Outer loop. ,g*!NK_:5t
SELECT @Counter = 0 FFHq':v
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) bO '\QtW9
BEGIN -- update $|K
d<wv
INSERT DummyTrans VALUES ('Fill Log') )vp0X\3q`
DELETE DummyTrans A1WUK=P
SELECT @Counter = @Counter + 1 jc^QWK*q
END Dg&84,bv^
EXEC (@TruncLog) 8{ zX=
END VF]AH}H8I
SELECT 'Final Size of ' + db_name() + ' LOG is ' + @Nu2
:~JO
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =L6#=7hcl
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^^y eC|~N:
FROM sysfiles Oy6fl'FIt
WHERE name = @LogicalFileName @MW@mP)#
DROP TABLE DummyTrans +y7z>Fwl
SET NOCOUNT OFF $a(-r-_Fi]
8、说明:更改某个表 @"@a70WHk
exec sp_changeobjectowner 'tablename','dbo' X>q`F;W
9、存储更改全部表 2
$>DX\h
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Fq9YhR
@OldOwner as NVARCHAR(128), _)A|JC!jId
@NewOwner as NVARCHAR(128) C2
N+X (
AS \Mf>X\}
DECLARE @Name as NVARCHAR(128) .;#T<S"
DECLARE @Owner as NVARCHAR(128) T$Z9F^w
DECLARE @OwnerName as NVARCHAR(128) fXD+
DECLARE curObject CURSOR FOR B#sCB&(
select 'Name' = name, wxN)dB
'Owner' = user_name(uid) m[DQ;`Y
from sysobjects Rr) 5[
where user_name(uid)=@OldOwner U82a]i0
order by name aDlp>p^E>
OPEN curObject `lhw*{3A
FETCH NEXT FROM curObject INTO @Name, @Owner kZ]H[\Fs
WHILE(@@FETCH_STATUS=0) U,P_bz*)
BEGIN FX:`7c]:9
if @Owner=@OldOwner +UzQJt/>>
begin 2u{~35
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !MbzFs~
exec sp_changeobjectowner @OwnerName, @NewOwner $vn6%M[
end rd <m:r
-- select @name,@NewOwner,@OldOwner QcegT/vO
FETCH NEXT FROM curObject INTO @Name, @Owner ts]e M1;
END }=R]<`Sj.j
close curObject J^!;$Hkd
deallocate curObject l#)X/(?;
GO G gO5=|
10、SQL SERVER中直接循环写入数据 n#_B4UqW%
declare @i int q'3{M]Tk
set @i=1 ''17(%
while @i<30
:e1h!G
begin =lacfPS
insert into test (userid) values(@i) A(Ct^/x-
set @i=@i+1 {v={q1
end Vax g
小记存储过程中经常用到的本周,本月,本年函数 kG^76dAQL
Dateadd(wk,datediff(wk,0,getdate()),-1) -@Ap;,=
Dateadd(wk,datediff(wk,0,getdate()),6) ns[/M~_r
Dateadd(mm,datediff(mm,0,getdate()),0) 8$FH;=
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) L!f~Am:#
Dateadd(yy,datediff(yy,0,getdate()),0) q~{)
{t;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) LKN7Lkl
上面的SQL代码只是一个时间段 c[@_t.%)
Dateadd(wk,datediff(wk,0,getdate()),-1) )Q2Ap&
Dateadd(wk,datediff(wk,0,getdate()),6) )k<cd.MX
就是表示本周时间段. ixTjXl2g
下面的SQL的条件部分,就是查询时间段在本周范围内的: &61U1"&$ R
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Sv =YI
而在存储过程中 iSfRJ:_&6
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) G?4@[m
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m:BzIcW<\