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。 M 3c
C^nTLw;K
($[)Tcq*~
一、基础 s.XLC43Rs
1、说明:创建数据库 |oV_7%mlu
CREATE DATABASE database-name }+i~JK
2、说明:删除数据库 f%Vdao[
drop database dbname zoHFTD4 g
3、说明:备份sql server p
_q]Rt
--- 创建 备份数据的 device [?nM)4d
USE master S)vNWBO
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =SLCG.
--- 开始 备份 .yb=I6D;<3
BACKUP DATABASE pubs TO testBack Kld#C51X f
4、说明:创建新表 S F&EVRv
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Kzrt%DA
根据已有的表创建新表: L5A?9zum/!
A:create table tab_new like tab_old (使用旧表创建新表) x$=""?dd
B:create table tab_new as select col1,col2... from tab_old definition only pDM95.6
5、说明:删除新表 DE" Y(;S
drop table tabname gkL{]*9&%
6、说明:增加一个列 1cY,)Z%l #
Alter table tabname add column col type `u#N
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。 sH /08Z
7、说明:添加主键: Alter table tabname add primary key(col) =w2_1F"
说明:删除主键: Alter table tabname drop primary key(col) /'Q2TLy=
8、说明:创建索引:create [unique] index idxname on tabname(col....) xBg.QV
删除索引:drop index idxname CCU<t
Q
注:索引是不可更改的,想更改必须删除重新建。 ;eT+Ly|{
9、说明:创建视图:create view viewname as select statement Or,W2
删除视图:drop view viewname :XeRc"m<
10、说明:几个简单的基本的sql语句 Tb<}GcwJ
选择:select * from table1 where 范围 w ^8i!jCy
插入:insert into table1(field1,field2) values(value1,value2) fe!{vrS
删除:delete from table1 where 范围 jC_m0Iwc
更新:update table1 set field1=value1 where 范围 c@/K}
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g<PglRr"
排序:select * from table1 order by field1,field2 [desc] m+9~f_}
总数:select count as totalcount from table1 y]b&3&
求和:select sum(field1) as sumvalue from table1 Qs7*_=+h
平均:select avg(field1) as avgvalue from table1 40Hm+Ge
最大:select max(field1) as maxvalue from table1 i4H,Ggb
最小:select min(field1) as minvalue from table1 ,@0D_&JAl
feG#*m2g
C] >?YR4
%#iu
11、说明:几个高级查询运算词 a/dq+
C5x*t Q|
7j8Ou3
A: UNION 运算符 -8m3L
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。 sX,S]:X
B: EXCEPT 运算符 ?OF9{$m3?
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ,WQg.neOA
C: INTERSECT 运算符 Sgq?r-Q.
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 xvTz|Y
注:使用运算词的几个查询结果行必须是一致的。 NGVl/Qd
12、说明:使用外连接 VQl(5\6O
A、left outer join: ,'&H`h54
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 JUdQ Q
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c y87oW_"h
B:right outer join: xj;V
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 OmLe+,7'
C:full outer join: *:V+whBY
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Z,7VOf6g
12HE=
<P.'r,"[
二、提升 U*:E|'>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ]'5 G/H5?;
法一:select * into b from a where 1<>1 'ZAl7k .
法二:select top 0 * into b from a ,v_NrX=f?
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) )>I-j$%=2
insert into b(a, b, c) select d,e,f from b; W.Z`kH *B
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) U6F1QLSLz
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Cxra(!&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. a9y+FCA
4、说明:子查询(表名1:a 表名2:b) t$g@+1p4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 3 @%XR8ss
5、说明:显示文章、提交人和最后回复时间 <d~si^*\ch
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b IQeiT[TF
6、说明:外连接查询(表名1:a 表名2:b) y7|
3]>Z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S pk8u4
7、说明:在线视图查询(表名1:a ) iB#*XJ;q
select * from (SELECT a,b,c FROM a) T where t.a > 1; lb\VQZp!y
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 4Be\5Byr
select * from table1 where time between time1 and time2 DhD^w;f]
select a,b,c, from table1 where a not between 数值1 and 数值2 D";@)\jN
9、说明:in 的使用方法 ?}"39n
select * from table1 where a [not] in ('值1','值2','值4','值6') 'wni.E&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 h&2l0|8k
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) fi [4F
11、说明:四表联查问题: %uDH_J|^
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Ticx]_+~T
12、说明:日程安排提前五分钟提醒 v-DZW,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Fs&r^ [/b
13、说明:一条sql 语句搞定数据库分页 t ^~Qv
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 FaQc@4%o
14、说明:前10条记录 uYC1}Y5N
select top 10 * form table1 where 范围 nYE%@Up
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) L :Ldk
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) n50WHlMtt
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Ui.S)\B
(select a from tableA ) except (select a from tableB) except (select a from tableC) DB3qf>@?
17、说明:随机取出10条数据 nM|F
MK^
select top 10 * from tablename order by newid() ~3Y4_b5E
18、说明:随机选择记录 c3.;o
select newid() ?OS0.
19、说明:删除重复记录 tmi)LRF
H
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) u(i=-PN_<
20、说明:列出数据库里所有的表名 i!EAs`$o`
select name from sysobjects where type='U' Oi<yT"7
21、说明:列出表里的所有的 5i+cjT2
select name from syscolumns where id=object_id('TableName') -tfUkGdx;l
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。 %Ni"*\
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 5GbC}y>
显示结果: xJ9aFpTC
type vender pcs \3`r/,wY
电脑 A 1 33g$mUB
电脑 A 1 dozC[4mF
光盘 B 2 \P7<q,OGS
光盘 A 2 %~L"TK`?
手机 B 3 ~z)JO'Z$
手机 C 3 ?[7KN8$
23、说明:初始化表table1 1>Q4&1Vn
TRUNCATE TABLE table1 Q89fXi0Ivb
24、说明:选择从10到15的记录 Z)md]Twt
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \/ipYc
}$i/4?dYsQ
9}5o> iR
VS >xvF
三、技巧 1!NrndJ I
1、1=1,1=2的使用,在SQL语句组合时用的较多 */2nh%>$
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~G 3txd
如: bEln.)
if @strWhere !='' o59b#9
begin 54=*vokX_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }(7TiCwd
end I-#7Oq:Np
else )D ~ 5
begin K&eT*JW>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' OX%#8Lx
end U7Oa
13Qz
我们可以直接写成 Bj<s!}i{[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4:5M,p
2、收缩数据库 )qe
rA
--重建索引 xpc{#/Nk
DBCC REINDEX yD#(Iw
DBCC INDEXDEFRAG Cz
&3=),G
--收缩数据和日志 :$0yp`k
DBCC SHRINKDB hZlHY9[t?
DBCC SHRINKFILE B<i(Y1n[
3、压缩数据库 zK&1ti@wln
dbcc shrinkdatabase(dbname) d0-4KN2
4、转移数据库给新用户以已存在用户权限 W^)mz,%x
exec sp_change_users_login 'update_one','newname','oldname' CK1A$$gnz
go IqiU
5、检查备份集 5RAhm0Op~.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qsQ{`E0
6、修复数据库 bi^Pk,'
ALTER DATABASE [dvbbs] SET SINGLE_USER Vl;zd=
GO fv k(eWB
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6%}`!_N<Mc
GO #ID
fJ2
ALTER DATABASE [dvbbs] SET MULTI_USER ) J.xQ}g
GO |1zfXG,R
7、日志清除 FPH2dN
SET NOCOUNT ON @yo6w}3+-
DECLARE @LogicalFileName sysname, 4EmdQn
@MaxMinutes INT, Lq;T\m_de
@NewSize INT iD*Hh-
USE tablename -- 要操作的数据库名 fp*6Dv_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 T<"Bb[kH
@MaxMinutes = 10, -- Limit on time allowed to wrap log. v>j,8E
@NewSize = 1 -- 你想设定的日志文件的大小(M) F]D{[dBf
-- Setup / initialize *@p"
DECLARE @OriginalSize int 8d_J9Ho
SELECT @OriginalSize = size RMiDV^.u`
FROM sysfiles UI"UBZZ$
WHERE name = @LogicalFileName `S0`3q}L3%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _QEw=*.<
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ;|0P\3
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' un4fnoc
FROM sysfiles Je,o(:
WHERE name = @LogicalFileName +80bG(I_
CREATE TABLE DummyTrans ;0Q" [[J
(DummyColumn char (8000) not null) ,n[<[tkCR
DECLARE @Counter INT, *5.wwV
@StartTime DATETIME, 1y\bJ
@TruncLog VARCHAR(255) @HPr;m!
SELECT @StartTime = GETDATE(), OTE,OCB[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' IT{c:jo1{`
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
PpKjjA<
EXEC (@TruncLog) zyhM*eM.7
-- Wrap the log if necessary. ^b$_I31D
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired (qvH=VTwP
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) jXLd#6
AND (@OriginalSize * 8 /1024) > @NewSize o$eCd{HuX
BEGIN -- Outer loop. ;mT}Q;F#
SELECT @Counter = 0 : NA(nA
3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3UaW+@
BEGIN -- update qZ'2M.;
INSERT DummyTrans VALUES ('Fill Log') qxDMDMN
DELETE DummyTrans "T{WOGU+
SELECT @Counter = @Counter + 1 Hy1$Kvub
END }Nd1'BVf
EXEC (@TruncLog) e4,SR(O>
END f;Oh"Yt
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Zp^O1&\SK?
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + v/9DD% An
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !Ve0 :$
FROM sysfiles w7.,ch
WHERE name = @LogicalFileName 1Acs0`3
DROP TABLE DummyTrans tsL
; wT_
SET NOCOUNT OFF l
_%<U
8、说明:更改某个表 ^8_yJ=~V
exec sp_changeobjectowner 'tablename','dbo' ]XbMqHGS
9、存储更改全部表 i@.Tv.NZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8toOdh
@OldOwner as NVARCHAR(128), =\|,hg)c
@NewOwner as NVARCHAR(128) %~x?C4L8
AS =PciLh
DECLARE @Name as NVARCHAR(128) C\;l)h_{
DECLARE @Owner as NVARCHAR(128) qFwt^w
DECLARE @OwnerName as NVARCHAR(128) icIn>i<m
DECLARE curObject CURSOR FOR n@xQ-v
select 'Name' = name, nq HpYb6I0
'Owner' = user_name(uid)
`YC7+`q
from sysobjects !u@P\8M}
where user_name(uid)=@OldOwner `BK b60
order by name "gJ.mhHX
OPEN curObject | bRU=dg
FETCH NEXT FROM curObject INTO @Name, @Owner bj}Lxc ],
WHILE(@@FETCH_STATUS=0) RrvC}9ar
BEGIN &Ap9h#
dK
if @Owner=@OldOwner VC/-5'_6
begin Qv5fK
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 38D5vT)n
exec sp_changeobjectowner @OwnerName, @NewOwner in/~' u
end w~)tEN>
-- select @name,@NewOwner,@OldOwner S'8+jY
FETCH NEXT FROM curObject INTO @Name, @Owner +^+'.xQ
END P%lD9<jED
close curObject s{R,- \_
deallocate curObject _%=CW'
B
GO 3 a.!9R>
10、SQL SERVER中直接循环写入数据 \?
)S{
declare @i int `DF49YP"~
set @i=1 /0H}-i
while @i<30 Gmi?xGn
begin .FHk1~\%z^
insert into test (userid) values(@i) G@#lf@M]
set @i=@i+1 On}1&!{1]
end /uX*FZ
小记存储过程中经常用到的本周,本月,本年函数 xws{"m,NX~
Dateadd(wk,datediff(wk,0,getdate()),-1) /nQuM05*Z
Dateadd(wk,datediff(wk,0,getdate()),6) c>K]$;}
Dateadd(mm,datediff(mm,0,getdate()),0) E&zf<Y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) -
[h[
Dateadd(yy,datediff(yy,0,getdate()),0) i7-~"g
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ^J#*sn
上面的SQL代码只是一个时间段 e|!'
Dateadd(wk,datediff(wk,0,getdate()),-1) O&BvWik
Dateadd(wk,datediff(wk,0,getdate()),6) fMg9h9U
就是表示本周时间段. dh7`eAMY
下面的SQL的条件部分,就是查询时间段在本周范围内的: NGSts\D'}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d/
^IL*O
而在存储过程中 /]3[|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) QR#>Ws
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) K~vJ/9"|R