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<f{7]fi5
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一、基础 @Q1jH~t
1、说明:创建数据库 +@qk=]3a
CREATE DATABASE database-name w+$gY?%
2、说明:删除数据库 X5/{Mx`8Oz
drop database dbname }Voh5*$E`
3、说明:备份sql server @>:07]Dxo
--- 创建 备份数据的 device n)7icSc
USE master 9G8QzIac
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 5)oIPHXw
--- 开始 备份 KE3
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BACKUP DATABASE pubs TO testBack -pGt;
4、说明:创建新表 eo_T.q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Q%xY/xH]
根据已有的表创建新表: +e:ZN
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A:create table tab_new like tab_old (使用旧表创建新表) +r!h* 4
B:create table tab_new as select col1,col2... from tab_old definition only S7q&|nI
5、说明:删除新表 2*L/c-
drop table tabname *pD;AU
6、说明:增加一个列 FVmg&[
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Alter table tabname add column col type |\(/dXXP
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。 QMxz@HGa|
7、说明:添加主键: Alter table tabname add primary key(col) 9h(hx7]
说明:删除主键: Alter table tabname drop primary key(col) GKtQ>39B
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?.4l1X6Ba
删除索引:drop index idxname ^aW[~ c
注:索引是不可更改的,想更改必须删除重新建。 ,6S8s
9、说明:创建视图:create view viewname as select statement u"gp">
删除视图:drop view viewname v+sbRuo8
10、说明:几个简单的基本的sql语句 )\;r
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选择:select * from table1 where 范围 Wd5t,8*8
插入:insert into table1(field1,field2) values(value1,value2) dZgfls
删除:delete from table1 where 范围 n_Y]iAoc`
更新:update table1 set field1=value1 where 范围 $bosGG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! P[K=']c
排序:select * from table1 order by field1,field2 [desc] 8!SiTOzR?
总数:select count as totalcount from table1 ~`E4E
求和:select sum(field1) as sumvalue from table1 &zcjU+n
平均:select avg(field1) as avgvalue from table1 (d#Z-w-
最大:select max(field1) as maxvalue from table1 { bn#:75r
最小:select min(field1) as minvalue from table1 Z5[:Zf?h7J
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11、说明:几个高级查询运算词 %Ab_PAw
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A: UNION 运算符 "J{zfWr
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,P@-DDJ
B: EXCEPT 运算符 ?\M6P?tpo&
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 8k^y.B
C: INTERSECT 运算符 ONiI:Z>%
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 9nS!
注:使用运算词的几个查询结果行必须是一致的。 <,4(3 >js
12、说明:使用外连接 4"x;XVNM[
A、left outer join: S5KYZ
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 oD@jtd>b%
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H<}eoU.
B:right outer join: y?#J`o-
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。
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C:full outer join: "nno)~)u
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 B~zg"
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二、提升 {FY[|:Cp
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?lN8~Ze
法一:select * into b from a where 1<>1 fbTw6Fde$
法二:select top 0 * into b from a l)*,18n
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %`1CE\f
insert into b(a, b, c) select d,e,f from b; >-5Gt
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) #x@lZ! Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `{lAhZ5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,]_(-tyN|
4、说明:子查询(表名1:a 表名2:b) q,+kPhHEgy
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) 355Sd;*
5、说明:显示文章、提交人和最后回复时间 Df:7P>
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) =Z .V+ 4+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2, "q_d'V
7、说明:在线视图查询(表名1:a ) oXlxPN39
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9_WPWFO
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 oA;Ty7s
select * from table1 where time between time1 and time2 A:bPIXb
select a,b,c, from table1 where a not between 数值1 and 数值2 u@_!mjXQ
9、说明:in 的使用方法 v;]I^Kq
select * from table1 where a [not] in ('值1','值2','值4','值6') ' q<EZ{
10、说明:两张关联表,删除主表中已经在副表中没有的信息 UcLNMn|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [}ZPg3Y
11、说明:四表联查问题:
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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 ..... s'aV q B
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s|gD
13、说明:一条sql 语句搞定数据库分页 iQ|,&K0d]
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 P A6KX5
14、说明:前10条记录 Go\} A:|s
select top 10 * form table1 where 范围 grCO-S|j^
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.) !q$&JZY
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :\+{;;a@
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 71l"m^Z3zy
(select a from tableA ) except (select a from tableB) except (select a from tableC) RJRq` T|m
17、说明:随机取出10条数据 ~S^X"8(U
select top 10 * from tablename order by newid() +-aU+7tu
18、说明:随机选择记录 @UpC{M--Wr
select newid() O| 1f^_S/
19、说明:删除重复记录 g>!:U6K
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) O J35En
20、说明:列出数据库里所有的表名 %]chL.s
select name from sysobjects where type='U' lP@)
21、说明:列出表里的所有的 dgco*TIGO
select name from syscolumns where id=object_id('TableName') s~Lfi.
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 WO.0K5nfk
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type MjQ[^%lfL
显示结果: Z#4JA/c!
type vender pcs :T7?
电脑 A 1 DIG0:)4R.
电脑 A 1 KbwTj*k[
光盘 B 2 JFG",09]
光盘 A 2 \6SMn6a4
手机 B 3 :F7k{~
手机 C 3 Jt2,LL:G
23、说明:初始化表table1 <AI>8j6#B
TRUNCATE TABLE table1 aJ:A%+1
24、说明:选择从10到15的记录 qnq%mwDeD
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc HQ^9[HN.
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三、技巧 jDlA<1
1、1=1,1=2的使用,在SQL语句组合时用的较多 x7"z(rKl
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `*e4m
如: LkJ$aW/
if @strWhere !='' W\it+/
begin r=fE8[,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;W7 hc!
end #_.g2 Y
else %{R_^Y8t
begin bK3B3r#$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1P_Fe[8
end bnijM/73
我们可以直接写成 Ln
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m|/q
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2、收缩数据库 Z?@oe-mz
--重建索引 O7})1|>1
DBCC REINDEX vq?aFX9F
DBCC INDEXDEFRAG mFGiysM
--收缩数据和日志 yJ0q)x sS
DBCC SHRINKDB 3EVAB0/$
DBCC SHRINKFILE F{'lF^Dc
3、压缩数据库 mdNIC
dbcc shrinkdatabase(dbname) 6Fe$'TP
4、转移数据库给新用户以已存在用户权限 9 SBVp6'
exec sp_change_users_login 'update_one','newname','oldname' _ Vo35kA
go GW;\3@o
5、检查备份集 8AGP*"gI
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3hD\6,@
6、修复数据库 :(?F(Q^
ALTER DATABASE [dvbbs] SET SINGLE_USER u]<_6;_
GO 'xG:v)(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK U3 -cH
GO Y}n$s/O:u8
ALTER DATABASE [dvbbs] SET MULTI_USER GN=ugP 9
GO lL$no7HBy
7、日志清除 >Ohh)$
SET NOCOUNT ON ?D,8lABkT
DECLARE @LogicalFileName sysname, !k}]` z^d
@MaxMinutes INT, K}feS(Ji
@NewSize INT |ctcY*+
USE tablename -- 要操作的数据库名 $xK*TJ(k
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 qOD:+b
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N!Cy)HnS\w
@NewSize = 1 -- 你想设定的日志文件的大小(M) a49xf^{1"i
-- Setup / initialize "3Lq/mJYnZ
DECLARE @OriginalSize int 4?c4GT9(6S
SELECT @OriginalSize = size EyK
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FROM sysfiles n#dvBK0M
WHERE name = @LogicalFileName -|WQs'%O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Qw@_.I
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ?E6C|A$I
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1:j[p=Q&
FROM sysfiles +#LD@)G
WHERE name = @LogicalFileName ZDl6F`
CREATE TABLE DummyTrans wj$WE3Y
(DummyColumn char (8000) not null) M\!z='Fi
DECLARE @Counter INT, ')82a49eA
@StartTime DATETIME, #[
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@TruncLog VARCHAR(255) T[\?fSP
SELECT @StartTime = GETDATE(), of<(4<T
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1R"?X'w
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6^#@y|.
EXEC (@TruncLog) ]N4?*S*jd)
-- Wrap the log if necessary. av:9kPKm
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .ZVADVg\
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _@_w6Rh
AND (@OriginalSize * 8 /1024) > @NewSize jT $
BEGIN -- Outer loop. 8;q2W
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SELECT @Counter = 0 EL gq#z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M\L^ Wf9
BEGIN -- update b!gvvg<
INSERT DummyTrans VALUES ('Fill Log') h3BDHz,
DELETE DummyTrans 56l1&hp8In
SELECT @Counter = @Counter + 1 EpdSsfDP
END ^E}};CsT
EXEC (@TruncLog) 4cQ|"sOzD
END 1
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + qf?X:9Wt
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + grbUR)f<?-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ) |Md"r_B
FROM sysfiles j3_vh<U\
WHERE name = @LogicalFileName i286`SLU
DROP TABLE DummyTrans $PbwC6>8
SET NOCOUNT OFF t(Sjo8,
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8、说明:更改某个表 kW.it5Z#
exec sp_changeobjectowner 'tablename','dbo' 9yWQ}h
9、存储更改全部表 q-5U,!!W/
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =ec"G2$?"
@OldOwner as NVARCHAR(128), [W,} &
@NewOwner as NVARCHAR(128) 3 6-Sw
AS $*N)\>~X
DECLARE @Name as NVARCHAR(128) kY.3x#w
DECLARE @Owner as NVARCHAR(128) Ce-D^9kC
DECLARE @OwnerName as NVARCHAR(128) 9TZ4ffXV*
DECLARE curObject CURSOR FOR Kq4b`cn{_
select 'Name' = name, #z&@f
'Owner' = user_name(uid) s:f%=4-7
from sysobjects 1_V',0|`>
where user_name(uid)=@OldOwner 8D5v'[j-
order by name bS"zp6Di
OPEN curObject TW)~&;1l
FETCH NEXT FROM curObject INTO @Name, @Owner H;k-@J
WHILE(@@FETCH_STATUS=0) #}|g8gh
BEGIN /+g)J0u
if @Owner=@OldOwner 4pG!m&4]ze
begin ~3r}6,%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Hy|
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exec sp_changeobjectowner @OwnerName, @NewOwner WB(Gx_o3
end k%2Rv4)hU
-- select @name,@NewOwner,@OldOwner lq*{2M{[
FETCH NEXT FROM curObject INTO @Name, @Owner GAY
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END 8-uRn38
close curObject Bkh1VAT
deallocate curObject wbA<G&h~
GO ,[{Z_co
10、SQL SERVER中直接循环写入数据 Aat-938FP6
declare @i int 3Sh#7"K3
set @i=1 [)L) R`
while @i<30 K! e51P
begin Yj/[I\I"m
insert into test (userid) values(@i) Z&[_8Y5j
set @i=@i+1 Trz41g
end Mlm dfO%Y
小记存储过程中经常用到的本周,本月,本年函数 A$;"9F@
Dateadd(wk,datediff(wk,0,getdate()),-1) _DAj$$ Ru4
Dateadd(wk,datediff(wk,0,getdate()),6) ne-;gTP;
Dateadd(mm,datediff(mm,0,getdate()),0) f\]splL
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) RZrQ^tI3"
Dateadd(yy,datediff(yy,0,getdate()),0) q{E44
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) zEN3Nn.8
上面的SQL代码只是一个时间段 {j!+\neL
Dateadd(wk,datediff(wk,0,getdate()),-1) /lqVMlz\77
Dateadd(wk,datediff(wk,0,getdate()),6) D/x!`&.sN
就是表示本周时间段. !,z==Qp|v
下面的SQL的条件部分,就是查询时间段在本周范围内的: y3{F\K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~]LkQQ'
而在存储过程中 unZYFA}(
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V_p[mSKJv
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) TOC2[mc'