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。 Q;GcV&f;f
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一、基础 }yw>d\] f
1、说明:创建数据库 _%(.OR
CREATE DATABASE database-name *0'< DnGW
2、说明:删除数据库 3 6t^iV*3
drop database dbname BDLJDyf B
3、说明:备份sql server `W.g1"o8W4
--- 创建 备份数据的 device QWE\Ud.q
USE master p$cb&NNh*H
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i!iG7X)qT
--- 开始 备份 [}dPn61
BACKUP DATABASE pubs TO testBack tTT
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4、说明:创建新表 e@iz`~[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) V>c !V9w
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) 8Yo;oHk7
B:create table tab_new as select col1,col2... from tab_old definition only MeV*]*
5、说明:删除新表 B qLL]%F
drop table tabname @U9`V&])F[
6、说明:增加一个列 dFmpx%+p
Alter table tabname add column col type ay]l\d2!3
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。 Y7;=\/SV
7、说明:添加主键: Alter table tabname add primary key(col) tl`x/
说明:删除主键: Alter table tabname drop primary key(col) ,.0B0Y-X
8、说明:创建索引:create [unique] index idxname on tabname(col....) D;[%*q*
删除索引:drop index idxname /4|_A {m{m
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement @76I8r5l
删除视图:drop view viewname zx@L sp
10、说明:几个简单的基本的sql语句 $i1:--~2\
选择:select * from table1 where 范围 Z+=-)&L
插入:insert into table1(field1,field2) values(value1,value2) $:&b5=i
删除:delete from table1 where 范围 ElK Md
更新:update table1 set field1=value1 where 范围 M>xT\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @^GI :z
排序:select * from table1 order by field1,field2 [desc] s\p 1EL(
总数:select count as totalcount from table1 a)I>Ns)
求和:select sum(field1) as sumvalue from table1 pJuD+v
平均:select avg(field1) as avgvalue from table1 '*^9'=
最大:select max(field1) as maxvalue from table1 "Y@q?ey[1
最小:select min(field1) as minvalue from table1 UhJ!7Ws$
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11、说明:几个高级查询运算词 7spZe"
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A: UNION 运算符 [z!pm-Ir
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。 =Aw`0
B: EXCEPT 运算符 1DGl[k/zv
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。 Z[>fFg~N4
C: INTERSECT 运算符 4p%^?L?
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。 ')/w+|F
注:使用运算词的几个查询结果行必须是一致的。 6OqF-nso[E
12、说明:使用外连接 VF g(:
A、left outer join: .[Qi4jm>`
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。 \fp'=&tp~a
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_7LSp
B:right outer join: ~(B%E'
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。 "=LeHY=9
C:full outer join: W }v
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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。 c'mg=jH
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二、提升 <p-@XzyE
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^ E.mG>
法一:select * into b from a where 1<>1 e X6o7a
法二:select top 0 * into b from a Q<KF<K'0hg
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) GMB3`&qh
insert into b(a, b, c) select d,e,f from b; ewWw
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) gtT&97tT<
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `g4N]<@z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. W|"bV 6d3
4、说明:子查询(表名1:a 表名2:b) 1(RRjT9
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) I:6XM?
5、说明:显示文章、提交人和最后回复时间 /1$u|Gs
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7|jy:F,w%
6、说明:外连接查询(表名1:a 表名2:b) VLJ]OW8cO
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c fxmY,{{
7、说明:在线视图查询(表名1:a ) ~z")';I|
select * from (SELECT a,b,c FROM a) T where t.a > 1; 3Tp8t6*nL
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 <N>7.G
select * from table1 where time between time1 and time2 g_Rp}6g
select a,b,c, from table1 where a not between 数值1 and 数值2 \HG4i/V:h
9、说明:in 的使用方法 |gHdTb1
select * from table1 where a [not] in ('值1','值2','值4','值6') H!Dj.]T
10、说明:两张关联表,删除主表中已经在副表中没有的信息 EBiLe;=X
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Z
11、说明:四表联查问题: O+/{[9s
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Zj_2B_|WN#
12、说明:日程安排提前五分钟提醒 '=xO?2U-Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 RCoDdtMo
13、说明:一条sql 语句搞定数据库分页 At
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ,H8M.hbsQ
14、说明:前10条记录 ii>^]iT
select top 10 * form table1 where 范围 /I{K_G@
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) .v+W>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) dBS_N/
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ~*]7f%L-
(select a from tableA ) except (select a from tableB) except (select a from tableC) G9GHBwT
17、说明:随机取出10条数据 06Q9X!xD
select top 10 * from tablename order by newid() s^4wn:*$zd
18、说明:随机选择记录 `^
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select newid() teC/Uf5
19、说明:删除重复记录 :Nwv&+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *YGj^+
20、说明:列出数据库里所有的表名 Y3s8@0b3
select name from sysobjects where type='U' m AET`B "
21、说明:列出表里的所有的 mN .
select name from syscolumns where id=object_id('TableName') L3'isaz&^
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。 xg 8R>j
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 :RwURv+kT
显示结果: qnnRS
type vender pcs 94|ZY}8|f
电脑 A 1 W]_a_5
电脑 A 1 BUV4L5(
光盘 B 2 %4t?X
光盘 A 2 k\9kOZW
手机 B 3 QDVSFGwr
手机 C 3 X.FoX
23、说明:初始化表table1 Bj9FSKiH
TRUNCATE TABLE table1 _HjB'XNr(
24、说明:选择从10到15的记录 lQ4^I^?m
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _MuzD&^qE
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三、技巧 `T{CB) ?9
1、1=1,1=2的使用,在SQL语句组合时用的较多 m1X*I
"where 1=1" 是表示选择全部 "where 1=2"全部不选, >[wB|V5
如: lj:.}+]r
if @strWhere !='' w=: c7Y+
begin p#-=mXE/2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {'B(S/Z7
end qh&q<M
else Z;BEUtR
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begin PRx- 0S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &;p}HL,
end #W
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我们可以直接写成 %_CL/H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [dUAb
2、收缩数据库 -o~n06p
--重建索引 aY;34SF
DBCC REINDEX "gzn%k[D9m
DBCC INDEXDEFRAG vu}U2 0@
--收缩数据和日志 'HCRi Z<
DBCC SHRINKDB ;l<Hen*
DBCC SHRINKFILE 49O_A[(d
3、压缩数据库 L{l}G,j<
dbcc shrinkdatabase(dbname) cKOXsdH?SL
4、转移数据库给新用户以已存在用户权限 /u`Opv&I
exec sp_change_users_login 'update_one','newname','oldname' 59v=\; UI
go Vpzjh,r-j
5、检查备份集 Y C<FKWc
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' w5rtYTI
6、修复数据库 6c27X/'Z
ALTER DATABASE [dvbbs] SET SINGLE_USER \
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GO wZbT*rU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $sZ4r>-
GO SG&H^V8
ALTER DATABASE [dvbbs] SET MULTI_USER f)gV2f0t
GO yx6^ mis4
7、日志清除 AE`UnlUSF
SET NOCOUNT ON n "^rS}Y]
DECLARE @LogicalFileName sysname, {f*{dSm9b
@MaxMinutes INT, |2=w":2#
@NewSize INT w@O)b-b|w
USE tablename -- 要操作的数据库名 7;C~>WlU
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3RxR'M1
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
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@NewSize = 1 -- 你想设定的日志文件的大小(M) CdcBE.%<
-- Setup / initialize p]?eIovi
DECLARE @OriginalSize int rg#/kd<?[V
SELECT @OriginalSize = size odJE~\\hw
FROM sysfiles H!,V7R
WHERE name = @LogicalFileName RdL5VAD
SELECT 'Original Size of ' + db_name() + ' LOG is ' + (^sb('"
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4ji'6JHPg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' xaV3N[Zd
FROM sysfiles +l!.<:sp
WHERE name = @LogicalFileName ,zH\P+*
CREATE TABLE DummyTrans xB?!nd
(DummyColumn char (8000) not null) @{Fa=".Ch
DECLARE @Counter INT, l&"bm C:xr
@StartTime DATETIME, v&%W*M0q@
@TruncLog VARCHAR(255) xdY'i0fh
SELECT @StartTime = GETDATE(), I$)9T^Ra
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' wdV)M?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0"+QWh
EXEC (@TruncLog) QJ>=a./
-- Wrap the log if necessary. cIkA ~F
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {!{T,_ J
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) D62'bFB^
AND (@OriginalSize * 8 /1024) > @NewSize f`\J%9U _O
BEGIN -- Outer loop. mUR[;;l
SELECT @Counter = 0 &9.3-E47*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5GPAt
BEGIN -- update k<f0moxs'
INSERT DummyTrans VALUES ('Fill Log') F8{T/YhZ
DELETE DummyTrans 66+]D4(k
SELECT @Counter = @Counter + 1 8JW0;H<
END J4iu8_eH!D
EXEC (@TruncLog) <Nc9F['
END \,:7=
SELECT 'Final Size of ' + db_name() + ' LOG is ' + wLt0Fq6QG
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 99]s/KD2yb
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' LUz`P6
FROM sysfiles y^kC2DS
WHERE name = @LogicalFileName L=s8em]7l
DROP TABLE DummyTrans Bxj4rC[
SET NOCOUNT OFF 36.mf_AM
8、说明:更改某个表 6(1
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exec sp_changeobjectowner 'tablename','dbo' W&Xi&[Ux
9、存储更改全部表 5"q{b1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch KpS=oFX{}
@OldOwner as NVARCHAR(128), <8Z%'C6d
@NewOwner as NVARCHAR(128) "/UPq6
AS w>Ft5"z
DECLARE @Name as NVARCHAR(128) T:CWxusL
DECLARE @Owner as NVARCHAR(128) (>Pz3 7
DECLARE @OwnerName as NVARCHAR(128) gq~`!tW'
DECLARE curObject CURSOR FOR `$3P@SO"
select 'Name' = name, mt e3k=17
'Owner' = user_name(uid) ,c;#~y
from sysobjects *|0W3uy\Y
where user_name(uid)=@OldOwner &qa16bz
order by name ZC^?ng
OPEN curObject pH@yE Vf
FETCH NEXT FROM curObject INTO @Name, @Owner _nw\ac#*
WHILE(@@FETCH_STATUS=0) Y!|};
BEGIN (.{. "
if @Owner=@OldOwner JKCV>k
begin Vt9o8naz
set @OwnerName = @OldOwner + '.' + rtrim(@Name) mcQ\"9 ;pY
exec sp_changeobjectowner @OwnerName, @NewOwner Th~pju
end (ueH@A"9;
-- select @name,@NewOwner,@OldOwner 6Hd^qouid
FETCH NEXT FROM curObject INTO @Name, @Owner D6e<1W
END *1>T c,mb
close curObject CyB1`&G>
deallocate curObject U[#q"'P|l
GO $.B}zY{
10、SQL SERVER中直接循环写入数据 ?:zMrlX
declare @i int
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set @i=1 'XSHl?+q
while @i<30 !yV)EJ:$
begin d{C8}U
insert into test (userid) values(@i) U2JxzHXZ
set @i=@i+1 mj9]M?]
end X<1ymb3
小记存储过程中经常用到的本周,本月,本年函数 [FWB
Dateadd(wk,datediff(wk,0,getdate()),-1) L;KLmxy#
Dateadd(wk,datediff(wk,0,getdate()),6) 9@*4^Ks p
Dateadd(mm,datediff(mm,0,getdate()),0) icK U)
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?C6`
Dateadd(yy,datediff(yy,0,getdate()),0) 8R;E+B{
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) BMhuM~?(
上面的SQL代码只是一个时间段 #`"B
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Dateadd(wk,datediff(wk,0,getdate()),-1) ;:Kc{B.s
Dateadd(wk,datediff(wk,0,getdate()),6) Mq6_Q07
就是表示本周时间段. `]Vn[^?D
下面的SQL的条件部分,就是查询时间段在本周范围内的: EkN>5).
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) kaCn@$
而在存储过程中 qEjsAL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 7G_lGV_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Aca?C