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。 r :-WfDz.
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一、基础 QLl44*@
1、说明:创建数据库 D40VJ3TUc
CREATE DATABASE database-name MWf%Lh;R
2、说明:删除数据库 *n5g";k|
drop database dbname ZVU)@[s
3、说明:备份sql server WU_Q
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--- 创建 备份数据的 device 8+F2
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USE master v8N1fuP}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' DLZ63'
--- 开始 备份 6}2Lt[>O
BACKUP DATABASE pubs TO testBack $=R\3:j
4、说明:创建新表 8/v_ uEG
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2Y{9Df
根据已有的表创建新表: !>j-j
A:create table tab_new like tab_old (使用旧表创建新表) >=Veu; A
B:create table tab_new as select col1,col2... from tab_old definition only 0IuU4h5Fr
5、说明:删除新表 OYy8u{@U:
drop table tabname 9,+LNZ'k
6、说明:增加一个列 +.St"f/1
Alter table tabname add column col type c7_b^7h1
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。 H;`@SJBf
7、说明:添加主键: Alter table tabname add primary key(col) GvY8O|a
说明:删除主键: Alter table tabname drop primary key(col) _`58G#z
8、说明:创建索引:create [unique] index idxname on tabname(col....) zV#k
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删除索引:drop index idxname St<\qC
注:索引是不可更改的,想更改必须删除重新建。 5Z{[.&x
9、说明:创建视图:create view viewname as select statement Ycm1 _z
删除视图:drop view viewname Dl6zl6q?
10、说明:几个简单的基本的sql语句 1|CO>)*D
选择:select * from table1 where 范围 0c)19Ig
插入:insert into table1(field1,field2) values(value1,value2) YQJ_t@0C
删除:delete from table1 where 范围 mi?Fy0\
更新:update table1 set field1=value1 where 范围 s!Vtwp9
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yMxS'j1
排序:select * from table1 order by field1,field2 [desc] i8F~$6C
总数:select count as totalcount from table1 ?jnEHn
求和:select sum(field1) as sumvalue from table1 x g@;d
平均:select avg(field1) as avgvalue from table1 anYZ"GR+
最大:select max(field1) as maxvalue from table1 6 ?cV1:jh
最小:select min(field1) as minvalue from table1 k9
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11、说明:几个高级查询运算词 w *0T"hK
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A: UNION 运算符 1Cthi[B
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Gf>T{Q`,is
B: EXCEPT 运算符 {S c1!2q
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 1Low[i
C: INTERSECT 运算符 z$A5p4=B'^
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。 r&w>+KIt
注:使用运算词的几个查询结果行必须是一致的。 UHHe~L
12、说明:使用外连接 JdnZY.{S0
A、left outer join: 3[$VW+YV
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 .KV?;{~q@
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k<y$[xV
B:right outer join: ?*g]27f11
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。 2C>PxA6l
C:full outer join: aj:+"X-;
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。 y g7z?AZ
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二、提升 <K~#@.^`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |<S9nZg%p
法一:select * into b from a where 1<>1 *|cvx:GO
法二:select top 0 * into b from a pn)5neX{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Sc(2c.HO*
insert into b(a, b, c) select d,e,f from b; mGX;JOjZ
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) 59LIK&w
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 iJAW| dw}
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. h$3Y,-4
4、说明:子查询(表名1:a 表名2:b) @/~41\=e
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) qe0@tKim
5、说明:显示文章、提交人和最后回复时间 ,}<v:!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b /#HY-b
6、说明:外连接查询(表名1:a 表名2:b) !&X}?NK
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c HV>W f"1
7、说明:在线视图查询(表名1:a ) CUoMB r
select * from (SELECT a,b,c FROM a) T where t.a > 1; MTQdyTDHl
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 sfH|sp
select * from table1 where time between time1 and time2 0&Qn7L
select a,b,c, from table1 where a not between 数值1 and 数值2 )pJzw-m"
9、说明:in 的使用方法 ?tBEB5
select * from table1 where a [not] in ('值1','值2','值4','值6') ;2$^=:8
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ky*-_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) F4@h}T5)
11、说明:四表联查问题: ][9M_.
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 ..... G[jCmkK
12、说明:日程安排提前五分钟提醒 hFKYRZtP.8
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 nBQG.3
13、说明:一条sql 语句搞定数据库分页 VFyt9:a
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 5s0H4 ?S
14、说明:前10条记录 edch'H^2+P
select top 10 * form table1 where 范围 n'&WIf3
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.) St?vd+(>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^+pmZw90
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 mZORV3bN
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,ihTEw,t(
17、说明:随机取出10条数据 ,30&VW##
select top 10 * from tablename order by newid() btee;3`
18、说明:随机选择记录 .DT1Jvl
select newid() pB )nQ5l'
19、说明:删除重复记录 6(wpf^br2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 1iz\8R:0
20、说明:列出数据库里所有的表名 sI`Lsd'V
select name from sysobjects where type='U' ^<<
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21、说明:列出表里的所有的 OyVp 3O
select name from syscolumns where id=object_id('TableName') "jy'Dpy0m
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。 atYm.qb
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@hv[4
显示结果: ")TI,a`
type vender pcs >kd2GZe^_J
电脑 A 1 FG'1;x!
电脑 A 1 i~4:]r22
光盘 B 2 W}KtB1J
光盘 A 2 .n"aQ@!
手机 B 3 e-Eoe_k
手机 C 3 G.9?ApG9
23、说明:初始化表table1 e+S%`Sg
TRUNCATE TABLE table1 jA6:-Gz
24、说明:选择从10到15的记录 a7Z PV1k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kfn5y#6NZ
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三、技巧 wAITE|H<zj
1、1=1,1=2的使用,在SQL语句组合时用的较多 8c#u"qF
"where 1=1" 是表示选择全部 "where 1=2"全部不选, & %1XYpA.0
如: &B[$l`1
if @strWhere !='' ?QZ\KY
begin 9c<lFZb;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere z"R-Sme
end q[r|p"TGov
else 5pz%DhjLo
begin 4e9mN~
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' D\>CEBt
end S&9{kt|BI
我们可以直接写成 !\CoJ.5=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^;N+"oq!y
2、收缩数据库 s fazrz`h
--重建索引 #;H+Kb5O
DBCC REINDEX >Efv?8$E\
DBCC INDEXDEFRAG 7\5;;23N4
--收缩数据和日志 ]^"*Fdn
DBCC SHRINKDB i9_ZK/*
DBCC SHRINKFILE ;g*ab
3、压缩数据库 S.BM/M
dbcc shrinkdatabase(dbname) 1S <V,9(
4、转移数据库给新用户以已存在用户权限 UT+B*?,h
exec sp_change_users_login 'update_one','newname','oldname' /9;)zI
go
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5、检查备份集 7\eN8+
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -k=02?0p+
6、修复数据库 Lylw('zZ
ALTER DATABASE [dvbbs] SET SINGLE_USER C;M.dd
GO *s<FE F
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !|hv49!H
GO N^B
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ALTER DATABASE [dvbbs] SET MULTI_USER na_Y<R`
GO &ciU`//`
7、日志清除 ]k5l]JB
SET NOCOUNT ON $#1i@dI
DECLARE @LogicalFileName sysname, //Ck1cI#h
@MaxMinutes INT, 0[jy
@NewSize INT q B5cF_
USE tablename -- 要操作的数据库名 7$k[cL1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +U%
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. {!@Pho) Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0 @~[SXR
-- Setup / initialize * 3WK`9q
DECLARE @OriginalSize int \-gZ_>)
SELECT @OriginalSize = size 1W;q(#q
FROM sysfiles 4l560Fb'U
WHERE name = @LogicalFileName L@XhgQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + zaf%%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (pNA8i%=G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' D^$Nn*i;U
FROM sysfiles H0_hQ:K
WHERE name = @LogicalFileName eo4;?z
CREATE TABLE DummyTrans 9=89)TrY
(DummyColumn char (8000) not null) /w$<0hH#'8
DECLARE @Counter INT, (g*2OS
@StartTime DATETIME, x~rIr#o
@TruncLog VARCHAR(255) I#tn/\n
SELECT @StartTime = GETDATE(), ;"Q{dOvp
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;J Fy
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) xQ=[0!p+
EXEC (@TruncLog) ^
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-- Wrap the log if necessary. q;1]M[&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !inonR
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :Em[>XA
AND (@OriginalSize * 8 /1024) > @NewSize [R TB|0Q
BEGIN -- Outer loop. AtGk
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SELECT @Counter = 0 ;<OIu&,*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3~iIo&NZ
BEGIN -- update |9$K'+'
INSERT DummyTrans VALUES ('Fill Log') [/.o>R#J(
DELETE DummyTrans 9X/c%:)\=
SELECT @Counter = @Counter + 1 WgF
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END T1.`*,t)=
EXEC (@TruncLog) u|z B\zd
END Ox#%Dm2
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ^&>(_I\w.6
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + "9:1>Gr{G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F
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FROM sysfiles +q[puFfl
WHERE name = @LogicalFileName a=>PGriL
DROP TABLE DummyTrans Ew~piuj
SET NOCOUNT OFF 3iMh)YH5b
8、说明:更改某个表 sg RY`U.C
exec sp_changeobjectowner 'tablename','dbo' 6&5p3G{%0
9、存储更改全部表
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch x'tYf^Va28
@OldOwner as NVARCHAR(128), n$i}r\
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@NewOwner as NVARCHAR(128) bX23F?
AS \#Ez["mD
DECLARE @Name as NVARCHAR(128) sS7r)HV&GI
DECLARE @Owner as NVARCHAR(128) ]{;=<t6
DECLARE @OwnerName as NVARCHAR(128) ?{ns1nW:
DECLARE curObject CURSOR FOR pHSq,XP-
select 'Name' = name, ()i8 Qepo}
'Owner' = user_name(uid) ;"l>HL:^
from sysobjects 4RTuy+
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where user_name(uid)=@OldOwner A8Tq2]"* S
order by name Ju4={^#
OPEN curObject L?T%;VdG'>
FETCH NEXT FROM curObject INTO @Name, @Owner M}MXR=X,
WHILE(@@FETCH_STATUS=0) O:3LA-vA
BEGIN ~OO&%\$k
if @Owner=@OldOwner a/Z >-
begin }c?/-ab>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) q'{LTg0kk
exec sp_changeobjectowner @OwnerName, @NewOwner 3eX;T +|o
end U`Bw2Vdk]S
-- select @name,@NewOwner,@OldOwner Uv?s <
FETCH NEXT FROM curObject INTO @Name, @Owner Q$r1beA
END ('BFy>@
close curObject OLp;eb1g
deallocate curObject J-yj&2
GO aUUr&yf_L
10、SQL SERVER中直接循环写入数据 ;dgxeP;mp
declare @i int ]Ng K(IU
set @i=1 g(){wCI
while @i<30 |d =1|C%,
begin /V}>v
insert into test (userid) values(@i) *Y(v!x \L
set @i=@i+1 uH 1%diL^
end X~wkqI#d%E
小记存储过程中经常用到的本周,本月,本年函数 JsAl;w
Dateadd(wk,datediff(wk,0,getdate()),-1) hqOy*!8'@
Dateadd(wk,datediff(wk,0,getdate()),6) w],+l N;
Dateadd(mm,datediff(mm,0,getdate()),0) %v
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6B>1"h%Wf
Dateadd(yy,datediff(yy,0,getdate()),0) S3EM6 `q'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Jv(9w[
上面的SQL代码只是一个时间段 H=b54.J8&
Dateadd(wk,datediff(wk,0,getdate()),-1) e}>8rnR{
Dateadd(wk,datediff(wk,0,getdate()),6) [ aC7
就是表示本周时间段. 8G@I e
下面的SQL的条件部分,就是查询时间段在本周范围内的: mkH{%7n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) O/b~TVA
而在存储过程中 g$+u;ER5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?`T<
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) :KY920/,