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。 {"33 .^=
qwAN=3@
JyPsRpi\
一、基础 2N]u!S ;d
1、说明:创建数据库 W":is"
CREATE DATABASE database-name muLt/.EZ
2、说明:删除数据库 i4TU}.h8
drop database dbname \'(
@{
3、说明:备份sql server 5ug?'TOj'
--- 创建 备份数据的 device Q(lj&!?1k
USE master |_l\.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' >V~q`htth
--- 开始 备份 @Z$`c{V<
BACKUP DATABASE pubs TO testBack @_0g "Ul
4、说明:创建新表 lD09(|`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) D
.3Q0a6
根据已有的表创建新表: C]aa^_Ldd-
A:create table tab_new like tab_old (使用旧表创建新表) yHW=,V.
B:create table tab_new as select col1,col2... from tab_old definition only o l67x
5、说明:删除新表 _] E ~ci}
drop table tabname # k+Ggw
6、说明:增加一个列
VQHJO I
Alter table tabname add column col type Vv(!Ki}
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 s{q)m@
7、说明:添加主键: Alter table tabname add primary key(col) { .KCK_ d
说明:删除主键: Alter table tabname drop primary key(col) *[*E|by
8、说明:创建索引:create [unique] index idxname on tabname(col....) p},6W,f
删除索引:drop index idxname iKB8V<[\T
注:索引是不可更改的,想更改必须删除重新建。 +Q, 0kv
9、说明:创建视图:create view viewname as select statement LV:oNK(
删除视图:drop view viewname IY|;}mIF
10、说明:几个简单的基本的sql语句 W5-p0,?[6
选择:select * from table1 where 范围 GE$spx
插入:insert into table1(field1,field2) values(value1,value2) R7us9qM4e
删除:delete from table1 where 范围 7BCCQsz<
更新:update table1 set field1=value1 where 范围 "s$v?voo
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8VvoPlo
排序:select * from table1 order by field1,field2 [desc] :oF\?e
总数:select count as totalcount from table1 yWIM,2x}
求和:select sum(field1) as sumvalue from table1 8WWRKP1V
平均:select avg(field1) as avgvalue from table1 g~d}?B\<@
最大:select max(field1) as maxvalue from table1 Egt;Bj#%
最小:select min(field1) as minvalue from table1 x8p#WB
|u)?h]>
&Pt|
LGT\1u
11、说明:几个高级查询运算词 e ,zR
/:>f$k4~h
Ygn"7
A: UNION 运算符 \()\pp~4
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 Q
NL){
B: EXCEPT 运算符 ]sO})
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。 rWbuoG+8
C: INTERSECT 运算符 !lE
(!d3M
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。 ,_`\c7@
注:使用运算词的几个查询结果行必须是一致的。 KdFQlQaj
12、说明:使用外连接 @Z!leyam
A、left outer join: zQxZR}'
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。 sS OI5W3A
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 +-,Q>`
B:right outer join: IoNZ'g?d
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。 MoA2Cp;8X
C:full outer join: GFvZdP`s4
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。 NTiJEzW}
'6{q;Bxo
1rC8]M.N
二、提升 cWgiFv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9A\J*OU
法一:select * into b from a where 1<>1 kgK7 T
法二:select top 0 * into b from a }jTE gog
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Js qze'BGY
insert into b(a, b, c) select d,e,f from b; YP~d1BWvf
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) -$;H_B+.
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 C 0*k@kGy
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. O:q}<ljp
4、说明:子查询(表名1:a 表名2:b) GZQ)TzR
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) J),7ukLu^
5、说明:显示文章、提交人和最后回复时间 c[< lr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [w~teX0!
6、说明:外连接查询(表名1:a 表名2:b) 7&NRE"?G
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c e~J% NU '&
7、说明:在线视图查询(表名1:a ) iAf, :g
select * from (SELECT a,b,c FROM a) T where t.a > 1; qsFA~{o.
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 oypq3V=5
select * from table1 where time between time1 and time2 MLmc]nL=
select a,b,c, from table1 where a not between 数值1 and 数值2 }*$-rieg
9、说明:in 的使用方法 ".v9#|
select * from table1 where a [not] in ('值1','值2','值4','值6') >U"f1q*$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .x6*9z#q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +n9&q#ah
11、说明:四表联查问题: cR$2`:e
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... BmUEo$w
12、说明:日程安排提前五分钟提醒 4cJ^L <
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *we 3i
13、说明:一条sql 语句搞定数据库分页 6luCi$bL
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 {exF"ap
14、说明:前10条记录 0$&Z_oJ
select top 10 * form table1 where 范围 \ ;Hj,z\
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.) >?M:oUVDU
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #x#.@
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 $a\q<fN}
(select a from tableA ) except (select a from tableB) except (select a from tableC) *~ 4uF
17、说明:随机取出10条数据 F.?:Gd1
select top 10 * from tablename order by newid() ` ]WU=Ss
18、说明:随机选择记录 wias]u|
select newid() Pc? d@tm
19、说明:删除重复记录 |kV,B_qz
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (h/v"dV;
20、说明:列出数据库里所有的表名 zo@>~G3$9
select name from sysobjects where type='U' AyNl,Xyc4
21、说明:列出表里的所有的 %Iv+Y$'3B
select name from syscolumns where id=object_id('TableName') \EYhAx`2
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。 ~,R_
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 |\?-k
显示结果: 3X0^xUA6
type vender pcs * _C6.%{
电脑 A 1 lqqY5l6j
电脑 A 1 ReKnvF~
光盘 B 2 8XX,(k_b
光盘 A 2 K"Nq_Ddwd
手机 B 3 M0c"wi@S_
手机 C 3 9]|[z{v'>l
23、说明:初始化表table1 ,2H5CFX/
TRUNCATE TABLE table1 ]t0?,q.$7
24、说明:选择从10到15的记录 a<!g*UVL0M
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc `ZV;Le'
z(1h ^.
~<v`&Gm?"
f(D?g
三、技巧 3m7$$N|
1、1=1,1=2的使用,在SQL语句组合时用的较多 f=~@e#U
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 2)[81a
如: qK|r+}g|&
if @strWhere !='' v .r$]O
begin 5I T'u3V
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^_5$+
end .RJvu$U2j
else Z`b,0[rG[
begin L$@RSKYp
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' n{4&('NRFP
end * +A!12s@
我们可以直接写成 vU{ZB^+&6o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )4GfT
2、收缩数据库 (nBJ,v)
--重建索引 Y ;&Cmi
DBCC REINDEX ,Hys9I
DBCC INDEXDEFRAG |r0j>F
--收缩数据和日志 Kn\Oj=4
DBCC SHRINKDB C6'[ Tn
DBCC SHRINKFILE *%Gy-5hM
3、压缩数据库 fM
S-
dbcc shrinkdatabase(dbname) 0pkU1t~9
4、转移数据库给新用户以已存在用户权限 Mv4JF(,S
exec sp_change_users_login 'update_one','newname','oldname' ;HqK^[1\
go f_raICO{R
5、检查备份集 9=3V}]^M
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "]MF =-v
6、修复数据库 ;=h^"et
ALTER DATABASE [dvbbs] SET SINGLE_USER NSHlo*)}
GO iy$]9Wf6=@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ) 3YE$,
GO P.;B
V",
ALTER DATABASE [dvbbs] SET MULTI_USER [&FMVM`
GO mhlJzGr*q
7、日志清除 +hXph
SET NOCOUNT ON zT_{M
qY
DECLARE @LogicalFileName sysname, -pqShDar|
@MaxMinutes INT, 'Iu$4xo`[
@NewSize INT xO?~@5
USE tablename -- 要操作的数据库名 *vBcT.|,
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zI7-xqZ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1/le%}mK
@NewSize = 1 -- 你想设定的日志文件的大小(M) mi97$Cr2
-- Setup / initialize (x.K%QC)
DECLARE @OriginalSize int KsUsj3J
SELECT @OriginalSize = size % j^=
FROM sysfiles EO'3;mo,
WHERE name = @LogicalFileName xZ,g6s2o
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "me Jn/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :kFWUs=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' I"@5=m5
FROM sysfiles fWKv3S1dT
WHERE name = @LogicalFileName [eWB
vAiW
CREATE TABLE DummyTrans uv_*E`pN~
(DummyColumn char (8000) not null) ~f% gW
DECLARE @Counter INT, ^lf;Lc
@StartTime DATETIME, /5yWvra
@TruncLog VARCHAR(255) N{Is2Ia
SELECT @StartTime = GETDATE(), 5,?9#n\E,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' .4-;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;AG5WPI
EXEC (@TruncLog) CH9#<?l
-- Wrap the log if necessary. Z#4? /'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired fep#Kb%"e
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U8<GD|
AND (@OriginalSize * 8 /1024) > @NewSize 2]>s@?[
BEGIN -- Outer loop. ~"=nt@M]
SELECT @Counter = 0 37lmB
'~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) /ebYk-c
BEGIN -- update Xv:<sX
INSERT DummyTrans VALUES ('Fill Log') UTs0=:+,t
DELETE DummyTrans Mw+]*
SELECT @Counter = @Counter + 1 YO-O-NEP
END 39m#
EXEC (@TruncLog) bR;H@Fdg?
END #;^.&2Lt
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PeE'#&wn
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + sKHUf1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \".3x
PkE
FROM sysfiles a_x|PbD
WHERE name = @LogicalFileName RqcX_x(p
DROP TABLE DummyTrans 7 v`Y*D
SET NOCOUNT OFF 9*,5R,#
8、说明:更改某个表 'MG)noN5
exec sp_changeobjectowner 'tablename','dbo' :&TOQ<vM
9、存储更改全部表 k#&y
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch XM8C{I1
@OldOwner as NVARCHAR(128), L"('gc!W
@NewOwner as NVARCHAR(128) gL}K84T$S
AS roRZE[ya
DECLARE @Name as NVARCHAR(128) }A2@1TTPX
DECLARE @Owner as NVARCHAR(128) g7d) YUc
DECLARE @OwnerName as NVARCHAR(128) $> #PhOC
DECLARE curObject CURSOR FOR /- kMzL
select 'Name' = name, X8*q[@$
'Owner' = user_name(uid) y'E)iI*
from sysobjects fNB*o={r|
where user_name(uid)=@OldOwner k92189B9j/
order by name yl3iU:+V
OPEN curObject t0?BU~f
FETCH NEXT FROM curObject INTO @Name, @Owner U15Hq*8Z
WHILE(@@FETCH_STATUS=0) yY,.GzIjCj
BEGIN Ye1P5+W(
if @Owner=@OldOwner [_H9l)
begin $9ON3>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /wvA]ooT
exec sp_changeobjectowner @OwnerName, @NewOwner A?6b)B/e?
end eUBk^C]\
-- select @name,@NewOwner,@OldOwner R8HA X
FETCH NEXT FROM curObject INTO @Name, @Owner *(r85lEou)
END p]pFZ";70
close curObject ]>`Q"g~0
deallocate curObject >:wk.<Z-
GO 9`c :sop
10、SQL SERVER中直接循环写入数据 LW,!B.`@
declare @i int m'429E]\S
set @i=1 k,q` ^E8k
while @i<30 zHu:Ec7
begin WddU|-W
insert into test (userid) values(@i)
?f &*mp
set @i=@i+1 KE(kR>OB]
end LXw&d]P
小记存储过程中经常用到的本周,本月,本年函数 B`KpaE]
Dateadd(wk,datediff(wk,0,getdate()),-1) 8qBw;A)
Dateadd(wk,datediff(wk,0,getdate()),6) _;0:wXib=
Dateadd(mm,datediff(mm,0,getdate()),0) rtUdL,Hx
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) G-}
zkax
Dateadd(yy,datediff(yy,0,getdate()),0) ew"[]eZ:ut
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) u`
上面的SQL代码只是一个时间段 v8wN2[fC
Dateadd(wk,datediff(wk,0,getdate()),-1) c"0CHrd
Dateadd(wk,datediff(wk,0,getdate()),6) sY1*WolA
就是表示本周时间段. ,~G[\2~p
下面的SQL的条件部分,就是查询时间段在本周范围内的: orL7y&w(v:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) wBmbn=>#S
而在存储过程中 ExnszFX*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vmmu[v
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Wje7fv