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。 mgxIxusR
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一、基础 ,N/@=As9$
1、说明:创建数据库 E' 5*w6
CREATE DATABASE database-name ~PQ.l\C
2、说明:删除数据库 BT{;^Hp
drop database dbname VFT@Ic#]
3、说明:备份sql server }ze+ tf
--- 创建 备份数据的 device !`ol&QQ#
USE master A#uU]S
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]{-.?W*$
--- 开始 备份 p<R:[rz
BACKUP DATABASE pubs TO testBack ^Fk;t
4、说明:创建新表 }v(wjD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) -luQbGcT3
根据已有的表创建新表: [f6uwp
A:create table tab_new like tab_old (使用旧表创建新表) 9#LMK 1ge
B:create table tab_new as select col1,col2... from tab_old definition only 6K2e]r
5、说明:删除新表 5s7BUT
drop table tabname ROO*/OOd
6、说明:增加一个列 ycGY5t@K@
Alter table tabname add column col type N_t,n^i9>*
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。 :\TMm>%q
7、说明:添加主键: Alter table tabname add primary key(col) A`c22Ls]
说明:删除主键: Alter table tabname drop primary key(col) 9rB3h`AVF
8、说明:创建索引:create [unique] index idxname on tabname(col....) ` Xc7b
删除索引:drop index idxname VA/2$5Wu
注:索引是不可更改的,想更改必须删除重新建。 !}*N';
9、说明:创建视图:create view viewname as select statement s8j |>R|k
删除视图:drop view viewname ]kh]l8t ^
10、说明:几个简单的基本的sql语句 vz^ ] g
选择:select * from table1 where 范围 u ExLj6
插入:insert into table1(field1,field2) values(value1,value2) p l)":}/)
删除:delete from table1 where 范围 68%aDs
更新:update table1 set field1=value1 where 范围 #h!+b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^[ae
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排序:select * from table1 order by field1,field2 [desc] +sNS
总数:select count as totalcount from table1 HC0juT OiO
求和:select sum(field1) as sumvalue from table1 ~Ps *i]n(
平均:select avg(field1) as avgvalue from table1 N,t9X7G&
最大:select max(field1) as maxvalue from table1 7j&
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最小:select min(field1) as minvalue from table1 LUbhTc
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11、说明:几个高级查询运算词 t@KTiJI
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A: UNION 运算符 (6,:X
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 7o4E_ .*
B: EXCEPT 运算符 [d`Jw/4n
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 K'OG-fn;
C: INTERSECT 运算符 D@=]mh6vl
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 l;$F[/3a
注:使用运算词的几个查询结果行必须是一致的。 j/v>,MM
12、说明:使用外连接 2OG/0cP
A、left outer join: 0 '&C5v'
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。 N'1I6e"
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 m:_#kfC&K"
B:right outer join: zD_5TGM=
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。 .0Ud?v>=
C:full outer join: 32GI+NN
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。 vc#o(?g
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二、提升 >N3X/8KL%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ? Fqh
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法一:select * into b from a where 1<>1 %Tp9GGt
法二:select top 0 * into b from a LP3#f{U
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) A-x^JC=
insert into b(a, b, c) select d,e,f from b; eI-fH
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) $.,PteYK
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (nqhX<T>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. s'O%@/;J
4、说明:子查询(表名1:a 表名2:b) +m_.?V6
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) +:A `e+\
5、说明:显示文章、提交人和最后回复时间 o*T?f)_[p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b F"Dr(V
6、说明:外连接查询(表名1:a 表名2:b) ;5X6`GlS#5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;LS.
7、说明:在线视图查询(表名1:a ) m?-)SA
select * from (SELECT a,b,c FROM a) T where t.a > 1; l6zAMyau5
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 besc7!S
select * from table1 where time between time1 and time2 p5In9s
select a,b,c, from table1 where a not between 数值1 and 数值2 c((3 B
9、说明:in 的使用方法 >A )Sl'
select * from table1 where a [not] in ('值1','值2','值4','值6') "t2T*'j{
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~HY)$Yp;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) `=Mk6$%Cs
11、说明:四表联查问题: HSud$(w
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 ..... &UDbH* !4=
12、说明:日程安排提前五分钟提醒 pIIp61=$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 y9}qB:[bR
13、说明:一条sql 语句搞定数据库分页 >$kFYb>~q
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 mjOxmwo
14、说明:前10条记录 ['QhC( {
select top 10 * form table1 where 范围 %>&~?zrq
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Rd(8j+Q?ps
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) n6[shXH
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 I/'>MDB!
(select a from tableA ) except (select a from tableB) except (select a from tableC) hMupQDv/I
17、说明:随机取出10条数据 "]^U(m>f
select top 10 * from tablename order by newid() +@$VJM%^7b
18、说明:随机选择记录 '4{@F~fu
select newid() Wz^;:6F
19、说明:删除重复记录 !,-'wT<v
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 52^3N>X4X
20、说明:列出数据库里所有的表名 %X\J%Fj
select name from sysobjects where type='U' X6sZwb
21、说明:列出表里的所有的 yO-2.2h
select name from syscolumns where id=object_id('TableName') lf\"6VIsR
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。 qY&(O`?m&
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 :WH{wm|
显示结果: :Gz$(!j1.'
type vender pcs .KYs5Qu
电脑 A 1 nUY)LnI
电脑 A 1 C\rT'!Uk\Q
光盘 B 2 FoIK, MdJ
光盘 A 2 ~m R^j
手机 B 3 !d0$cF):
手机 C 3 [3irr0D7l
23、说明:初始化表table1 1`II%mf[
TRUNCATE TABLE table1 ~+6#4<M.~
24、说明:选择从10到15的记录 d+Mogku2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G>Bgw>#_
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三、技巧 p-C{$5&
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1、1=1,1=2的使用,在SQL语句组合时用的较多 1>_$O|dE
"where 1=1" 是表示选择全部 "where 1=2"全部不选, q89yW)XG
如: v&sp;%I6=
if @strWhere !='' 823y;
begin qvsfU*wo?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |rpMwkR
end HVC|0}
else M/[9ZgDc
begin WUDXx %
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' HDo=W qG
end N}|1oQkjf
我们可以直接写成 $
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere oOQan
2、收缩数据库 4!glgEE*
--重建索引 L8;`*H
DBCC REINDEX .<P@6Jq
DBCC INDEXDEFRAG Mi!ak
--收缩数据和日志 IxP$lx
DBCC SHRINKDB /[3!kW
DBCC SHRINKFILE ~O~we
3、压缩数据库
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dbcc shrinkdatabase(dbname) +c'I7bBr
4、转移数据库给新用户以已存在用户权限 @[(%b{TE;
exec sp_change_users_login 'update_one','newname','oldname' |qk%UN<
go Z${@;lgP
5、检查备份集 :)e/(I]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ]o8~b-
6、修复数据库 piUfvw
ALTER DATABASE [dvbbs] SET SINGLE_USER ku5g`ho
GO el0W0T
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK d#- <=6
GO V> eJ
ALTER DATABASE [dvbbs] SET MULTI_USER H%c{ }F
GO 2wh{[Q2f
7、日志清除 6~+?DIc
SET NOCOUNT ON PI")^`
DECLARE @LogicalFileName sysname, PJcz] <
@MaxMinutes INT, Boa?Ghg
@NewSize INT w<4){.dA
USE tablename -- 要操作的数据库名 w*N9p8hb]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 T\HP5&
@MaxMinutes = 10, -- Limit on time allowed to wrap log. "V_PWEi
@NewSize = 1 -- 你想设定的日志文件的大小(M) j#XU\G
-- Setup / initialize b+}*@xhl
DECLARE @OriginalSize int Q ?W6
SELECT @OriginalSize = size z[, `
FROM sysfiles E~!FEl;
WHERE name = @LogicalFileName 4~r=[|(aY
SELECT 'Original Size of ' + db_name() + ' LOG is ' + D&)gcO`\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WxLILh
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' hAZ"M:f
FROM sysfiles &"svt2
WHERE name = @LogicalFileName #P6;-d@a
CREATE TABLE DummyTrans {z%%(,I
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, ex2*oqAdX
@StartTime DATETIME, L``K. DF
@TruncLog VARCHAR(255) LNU9M>
SELECT @StartTime = GETDATE(), 5k}UXRB?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1k>*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ',*
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EXEC (@TruncLog) Z5{M_^
-- Wrap the log if necessary. p.1|bXY`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {/ _.]Vh
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) D &wm7,
AND (@OriginalSize * 8 /1024) > @NewSize *%cI,}%
BEGIN -- Outer loop. T3{qn$t8
SELECT @Counter = 0
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'bg%9}
BEGIN -- update ]Ikj Z=
INSERT DummyTrans VALUES ('Fill Log') S?=2GY
DELETE DummyTrans ;xa]ke3]
SELECT @Counter = @Counter + 1 zUxF"g-W
END Oox5${#^
EXEC (@TruncLog) ]?Ru~N}
END z{^XU"yB
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PHD$E s
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + i@_|18F]`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' s\Cl3
FROM sysfiles :h3
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WHERE name = @LogicalFileName te'<xfG
DROP TABLE DummyTrans +Mv0X%(N
SET NOCOUNT OFF +3t(kQ
8、说明:更改某个表 2Sb~tTGz79
exec sp_changeobjectowner 'tablename','dbo' Qo{^jDe,c*
9、存储更改全部表 +]|J
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch mnXaf)"
@OldOwner as NVARCHAR(128), )r1Z}X(#d
@NewOwner as NVARCHAR(128) mrd(\&EhA
AS P[ KJuc
DECLARE @Name as NVARCHAR(128) -D.6@@%Kc}
DECLARE @Owner as NVARCHAR(128) "mT~_BsD
DECLARE @OwnerName as NVARCHAR(128) ;Fuxj!gF
DECLARE curObject CURSOR FOR J/wot,j^
select 'Name' = name, +|(
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'Owner' = user_name(uid) x%x:gkq
from sysobjects K#F~$k|1B
where user_name(uid)=@OldOwner zYSXG-k
order by name ]Wv\$JXI
OPEN curObject P RX:*0
FETCH NEXT FROM curObject INTO @Name, @Owner '1r:z, o|
WHILE(@@FETCH_STATUS=0) UmQ 9_H 7
BEGIN iQin|$F_O
if @Owner=@OldOwner yNY1g?E
begin %wvSD&oz
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 18ci-W#p
exec sp_changeobjectowner @OwnerName, @NewOwner NY1olnI
end AytHnp\H
-- select @name,@NewOwner,@OldOwner O2Rv^la
FETCH NEXT FROM curObject INTO @Name, @Owner ;U}lh~e11
END g4j?E{M?
close curObject ='OPU5(;O
deallocate curObject tq>QZEg
GO "2 qp-'^[c
10、SQL SERVER中直接循环写入数据 ?exV:OKLb
declare @i int Ge[N5N>
set @i=1 ](-:l6
while @i<30 A*~zdZ p
begin Alp9]
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insert into test (userid) values(@i) o& $Fc8bH
set @i=@i+1 )>$xbo")k
end eSywWSdf0
小记存储过程中经常用到的本周,本月,本年函数 9)T;.O
Dateadd(wk,datediff(wk,0,getdate()),-1) S1;#58
Dateadd(wk,datediff(wk,0,getdate()),6) nY}Ep\g
Dateadd(mm,datediff(mm,0,getdate()),0) SukRJvi
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) SH5GW3\h
Dateadd(yy,datediff(yy,0,getdate()),0) [ZOo%"M_Y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Uq0RJ<n
上面的SQL代码只是一个时间段 86@"BNnTh
Dateadd(wk,datediff(wk,0,getdate()),-1) SgFyv<6>:
Dateadd(wk,datediff(wk,0,getdate()),6) *V3 }L
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就是表示本周时间段. `gD'q5.z;3
下面的SQL的条件部分,就是查询时间段在本周范围内的: @+:S'mAQC
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) p@NE^aMn
而在存储过程中 &D>e>]E|P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Iz!Blk
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) a` 95eL}