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。 ?U3~rro!
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一、基础 \kP1 Jr
1、说明:创建数据库 ?*:BgaR_
CREATE DATABASE database-name bKQ_{cR
2、说明:删除数据库 }BAe
drop database dbname #{5h6IC
3、说明:备份sql server "10.,QK
--- 创建 备份数据的 device " nLWvV1
USE master Lklb
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0}9
--- 开始 备份 ld7B{ ?]
BACKUP DATABASE pubs TO testBack Da
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4、说明:创建新表 '5\?l:z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) d RHw]!.
根据已有的表创建新表: x,Z:12H0
A:create table tab_new like tab_old (使用旧表创建新表) @=qWwt4~
B:create table tab_new as select col1,col2... from tab_old definition only s]Z++Lh<{
5、说明:删除新表 /2Bf6
drop table tabname uOJso2Mx
6、说明:增加一个列 "@L|Z6U(
Alter table tabname add column col type B~`:?f9ny5
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。 :oytJhxU
7、说明:添加主键: Alter table tabname add primary key(col) , RU
说明:删除主键: Alter table tabname drop primary key(col) 4okZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?'U@oz8 B
删除索引:drop index idxname dC?l%,W
注:索引是不可更改的,想更改必须删除重新建。 Q#pgl
9、说明:创建视图:create view viewname as select statement IYe ,VL
删除视图:drop view viewname PDb7 h
10、说明:几个简单的基本的sql语句 4R&pb1eF
选择:select * from table1 where 范围 M<ba+Qn$
插入:insert into table1(field1,field2) values(value1,value2) 86W.z6
删除:delete from table1 where 范围 BP=<TRp.
更新:update table1 set field1=value1 where 范围 ,yTT,)@<
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Xbc:Vr
排序:select * from table1 order by field1,field2 [desc] Oe&gTXo
总数:select count as totalcount from table1 A[H"(E#k
求和:select sum(field1) as sumvalue from table1 jBJ|%KM
平均:select avg(field1) as avgvalue from table1 )OZ
最大:select max(field1) as maxvalue from table1 v4r%'bA
最小:select min(field1) as minvalue from table1 i*e'eZ;)
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11、说明:几个高级查询运算词 )@6iQ
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A: UNION 运算符 zRgl`zREr
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。 ~y1k2n
B: EXCEPT 运算符 T*rz#O
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。 B1 xlWdm
C: INTERSECT 运算符 oI x!?,1
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。 8YO` TgW
注:使用运算词的几个查询结果行必须是一致的。 v8\pOI}c
12、说明:使用外连接 vO8CT-)
A、left outer join: ~;I'.TW
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。 Gy!bPVe
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 b#Vm;6BHD1
B:right outer join: 9O-*iK
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。 8\m[Nuq5
C:full outer join: vzZ"TSP
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。 9KMtPBZ
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二、提升 :7pt=IA
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) (ljoD[kZ
法一:select * into b from a where 1<>1 /\5u-o)
法二:select top 0 * into b from a
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jiP^Hz"e
insert into b(a, b, c) select d,e,f from b; v.Xmrry
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) D>K=D"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 i 8:^1rHp)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &\<?7Qj3U|
4、说明:子查询(表名1:a 表名2:b) YH{FTVOt{C
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) e# KP3Lp
5、说明:显示文章、提交人和最后回复时间 n(jrK9]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |/;X-+f8
6、说明:外连接查询(表名1:a 表名2:b) t8t+wi!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o<7'(Pz
7、说明:在线视图查询(表名1:a ) A'T: \Wl
select * from (SELECT a,b,c FROM a) T where t.a > 1; 90!67Ap`x
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 D*!9K8<o
select * from table1 where time between time1 and time2 Vn6]h|vm
select a,b,c, from table1 where a not between 数值1 and 数值2 pxHJX2
9、说明:in 的使用方法 Il$Jj-)
select * from table1 where a [not] in ('值1','值2','值4','值6') AHn
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 YbuS[l8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) DQ= /Jr~
11、说明:四表联查问题: L*1yK*
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 ..... io*iA<@Gx
12、说明:日程安排提前五分钟提醒 1D)=q^\I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 YFs!,fw'
13、说明:一条sql 语句搞定数据库分页 %#@5(_'
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 $WG<
14、说明:前10条记录 `h$^=84
select top 10 * form table1 where 范围 2Z*^)ZQB
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.) 5VGr<i&A
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6_O3/
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 WXCZ
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(select a from tableA ) except (select a from tableB) except (select a from tableC) Oi\,clR^[o
17、说明:随机取出10条数据 td(4Fw||1y
select top 10 * from tablename order by newid() 9NausE40
18、说明:随机选择记录 ^THyohK
select newid() Q ;$NDYV1
19、说明:删除重复记录 &v<Am%!N
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?m dGMf)
20、说明:列出数据库里所有的表名 '*n2<y
select name from sysobjects where type='U' ,")/R/d
21、说明:列出表里的所有的 ~a`
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select name from syscolumns where id=object_id('TableName') eX <@qa4<
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 '+E\-X
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type GbJVw\5Z*
显示结果: i|QL6e*0
type vender pcs )G@/E^ySM
电脑 A 1
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电脑 A 1 Yo[Pu< zR
光盘 B 2 Qs;MEt 1
光盘 A 2 {V5eHn9/Q'
手机 B 3 )1o<}7
手机 C 3 i=X
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23、说明:初始化表table1 s!WI:E7
TRUNCATE TABLE table1 |oV_7%mlu
24、说明:选择从10到15的记录 }+i~JK
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (5Sv$Xt
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三、技巧 ?$Ii_.
1、1=1,1=2的使用,在SQL语句组合时用的较多 A,]%*kg2
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Rg~F[j$N
如: DE" Y(;S
if @strWhere !='' -1c{Jo
begin ^=7XA894
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R&9Q#n-
end jRNDi_u?Wb
else HAc1w]{(
begin [WW ~SOJe
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' x5 ?>y{6D
end ; )rXQm
我们可以直接写成 Pj{Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere E>Lgf&R#W
2、收缩数据库 k07pI<a?
--重建索引 p@iU9K\,
DBCC REINDEX 'rDai[
DBCC INDEXDEFRAG C5x*t Q|
--收缩数据和日志 ^s_7-p])(
DBCC SHRINKDB ?yy,3:
DBCC SHRINKFILE _FtsO<p)"
3、压缩数据库 V3c7F4\
dbcc shrinkdatabase(dbname) W?X3 :1c9:
4、转移数据库给新用户以已存在用户权限 !?5YXI,
exec sp_change_users_login 'update_one','newname','oldname' %hCd*[Z}j
go olca
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5、检查备份集 LGT?/gup
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' OmLe+,7'
6、修复数据库 `/JuItL-
ALTER DATABASE [dvbbs] SET SINGLE_USER }0idFotck
GO zLybf:#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /MZ^;XG
GO Aqo90(jffx
ALTER DATABASE [dvbbs] SET MULTI_USER W(\^6S)
GO {.o@XP,.
7、日志清除 AH?4F"
SET NOCOUNT ON ug^esB
DECLARE @LogicalFileName sysname, {3!E8~
@MaxMinutes INT, '^%k TNn
@NewSize INT 4Be\5Byr
USE tablename -- 要操作的数据库名 D";@)\jN
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 cG,zO-H
@MaxMinutes = 10, -- Limit on time allowed to wrap log. /X%+z5
@NewSize = 1 -- 你想设定的日志文件的大小(M) ip!-~HNwJ
-- Setup / initialize >)+N$EN
DECLARE @OriginalSize int t ^~Qv
SELECT @OriginalSize = size IR|#]en
FROM sysfiles '
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WHERE name = @LogicalFileName 9J$-E4G.M
SELECT 'Original Size of ' + db_name() + ' LOG is ' + sW@_' Lw
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ZQ{-6VCjl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z}S7%m
FROM sysfiles u=t.1eS5
WHERE name = @LogicalFileName {r'+icvLX
CREATE TABLE DummyTrans XIn,nCY;
(DummyColumn char (8000) not null) 'OvM
DECLARE @Counter INT, LkXho>y
@StartTime DATETIME, Lg{M<Q)4
@TruncLog VARCHAR(255) hkMVA
SELECT @StartTime = GETDATE(), #mkf2Z=t-
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Bk[C=< X
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
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EXEC (@TruncLog) )Z)Gb~G
-- Wrap the log if necessary. Kc,i$FH
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Xw3j(`w$,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) c(aykIVOo
AND (@OriginalSize * 8 /1024) > @NewSize FLXn%/
BEGIN -- Outer loop. T^vhhfCUr
SELECT @Counter = 0 tAsap}(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) S%aup(wu6
BEGIN -- update f-p$4%(
INSERT DummyTrans VALUES ('Fill Log') 4AMe>s
DELETE DummyTrans `x_}mdR
SELECT @Counter = @Counter + 1 t
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END =#=}|Q}
EXEC (@TruncLog) @)U;hk)j;
END !o1IpTN
SELECT 'Final Size of ' + db_name() + ' LOG is ' + @JGFG+J}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + huW,kk<]y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]|tR8`DGZ%
FROM sysfiles h,n}=g+?
WHERE name = @LogicalFileName %-a;HGbZn
DROP TABLE DummyTrans t+_\^Oa)
SET NOCOUNT OFF t<ZBp0
8、说明:更改某个表 z%#-2&i
exec sp_changeobjectowner 'tablename','dbo' 3dlY_z=0
9、存储更改全部表 1\~I "$}
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch < Sgc6>)
@OldOwner as NVARCHAR(128), -+Ot'^
@NewOwner as NVARCHAR(128) 1wFW&|>1
AS *CPp U|
DECLARE @Name as NVARCHAR(128) K_~kL0=4
DECLARE @Owner as NVARCHAR(128) x;<0Gg~jB
DECLARE @OwnerName as NVARCHAR(128) @HPr;m!
DECLARE curObject CURSOR FOR IT{c:jo1{`
select 'Name' = name, H(gY=
'Owner' = user_name(uid) )z\#
from sysobjects kDDC@A $
where user_name(uid)=@OldOwner l5.k2{'
order by name DxwR&S{
OPEN curObject URs]S~tk
FETCH NEXT FROM curObject INTO @Name, @Owner /,\U*'-
WHILE(@@FETCH_STATUS=0) 8lzoiA_9
BEGIN [^s;Ggi9
if @Owner=@OldOwner ?_d6;
begin 3]GMQA{L)
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5a'`%b{{
exec sp_changeobjectowner @OwnerName, @NewOwner Jx~H4y=z
end r5N TTc
-- select @name,@NewOwner,@OldOwner 7P<f(@0h$E
FETCH NEXT FROM curObject INTO @Name, @Owner kl]MP}wc
END )v_v 7 ~H&
close curObject Jw8?o/1D@
deallocate curObject `-.2Z
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GO g(9* !g
10、SQL SERVER中直接循环写入数据 bj}Lxc ],
declare @i int &Ap9h#
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set @i=1 h?p_jI
while @i<30 g i6s+2
begin l=p_
insert into test (userid) values(@i) iuGwc086
set @i=@i+1 Fz';H
end 7)V"E-6h
小记存储过程中经常用到的本周,本月,本年函数 l[c '%M |N
Dateadd(wk,datediff(wk,0,getdate()),-1) 8 5X}CCQ
Dateadd(wk,datediff(wk,0,getdate()),6) e)n ,Y
Dateadd(mm,datediff(mm,0,getdate()),0) $QwpoVp`~
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /nQuM05*Z
Dateadd(yy,datediff(yy,0,getdate()),0) MGsQF #6]
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) myR{}G
上面的SQL代码只是一个时间段 lQ`=PFh
Dateadd(wk,datediff(wk,0,getdate()),-1) TT/H"Ri}Jp
Dateadd(wk,datediff(wk,0,getdate()),6) d/
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就是表示本周时间段. QR#>Ws
下面的SQL的条件部分,就是查询时间段在本周范围内的: 17Cb{Q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) BYX c
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而在存储过程中 < ,0D|O,Y
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V^n6~O
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) vvv'!\'#