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。 {Hv/|.),hu
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一、基础 (XQBBt
1、说明:创建数据库 [hLSK-K 9
CREATE DATABASE database-name )zFPf]gz
2、说明:删除数据库 &8l"Dl
drop database dbname j^t#>tZS
3、说明:备份sql server F__(iXxC
--- 创建 备份数据的 device 9]ga\>v
USE master x=UwyZ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :MOr?"
--- 开始 备份 ICJp-
BACKUP DATABASE pubs TO testBack Ez3>}E,
4、说明:创建新表 ?!N@%R>5rN
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hdi/ k!9[\
根据已有的表创建新表: d"E@e21
A:create table tab_new like tab_old (使用旧表创建新表) Mr5E\~K>s
B:create table tab_new as select col1,col2... from tab_old definition only @~4Q\^;NX
5、说明:删除新表 e?Pzhha
drop table tabname F,t
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6、说明:增加一个列 Fk:yj 4'
Alter table tabname add column col type QY]^^f
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。 SR,id B&i
7、说明:添加主键: Alter table tabname add primary key(col) bN Ub
说明:删除主键: Alter table tabname drop primary key(col) mkA1Sh{hX>
8、说明:创建索引:create [unique] index idxname on tabname(col....) RXMzwk
删除索引:drop index idxname x@-bY
注:索引是不可更改的,想更改必须删除重新建。 aoLYw 9
9、说明:创建视图:create view viewname as select statement XZ@;Tyn0,
删除视图:drop view viewname }U)g<Kzh
10、说明:几个简单的基本的sql语句 >L\>Th{o
选择:select * from table1 where 范围 EcBJ-j6d
插入:insert into table1(field1,field2) values(value1,value2) Y9b|lP7!
删除:delete from table1 where 范围 uQ^r1 $#
更新:update table1 set field1=value1 where 范围 ^E)Kse.>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! a3&&7n
排序:select * from table1 order by field1,field2 [desc] 2"31k2H[
总数:select count as totalcount from table1 q/
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求和:select sum(field1) as sumvalue from table1 z9@Tg=#i
平均:select avg(field1) as avgvalue from table1 $1QQidB
最大:select max(field1) as maxvalue from table1 s0}OsHAj
最小:select min(field1) as minvalue from table1 @yBg)1AL
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11、说明:几个高级查询运算词 iKy_DV;J
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A: UNION 运算符 h$#QRH
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。 K`=O!;
B: EXCEPT 运算符
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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。 *
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C: INTERSECT 运算符 f0uzoeL<%
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)>/P{A-P
注:使用运算词的几个查询结果行必须是一致的。 o80"ZU|=
12、说明:使用外连接 GpjyF_L
A、left outer join: %/l9$>{
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 8>Y
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c q Ee1OB
B:right outer join: 8.-0_C*U;
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 RC_w 1:h
C:full outer join: OYw~I.Rq
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 !.\EU*)1
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二、提升 2$>"4
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) v/n4Lp$W^
法一:select * into b from a where 1<>1 \a:#e%]qz9
法二:select top 0 * into b from a (1~d/u?2\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7
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insert into b(a, b, c) select d,e,f from b; sV8}Gv
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) H4s^&--
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =0te.io)3O
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 7Ao9MF-
4、说明:子查询(表名1:a 表名2:b) gWt}q-@nRR
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) J%G
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5、说明:显示文章、提交人和最后回复时间 vwVK^B
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~F?vf@k
6、说明:外连接查询(表名1:a 表名2:b) /az}<r8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .A;e`cKb
7、说明:在线视图查询(表名1:a ) Z`5jX;Z!
select * from (SELECT a,b,c FROM a) T where t.a > 1; X$o$8s
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ?2hS<qXX
select * from table1 where time between time1 and time2 E kb9=/
select a,b,c, from table1 where a not between 数值1 and 数值2 r-M:YB
9、说明:in 的使用方法 +.Pv:7gh
select * from table1 where a [not] in ('值1','值2','值4','值6') k)Y}X)\36
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ^
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i$~2pr
11、说明:四表联查问题: N=1zhI:VaQ
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 ..... AJk0jh\.j%
12、说明:日程安排提前五分钟提醒 P5u
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 dGxk
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13、说明:一条sql 语句搞定数据库分页 r)ni;aP
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 mR3)$!
14、说明:前10条记录 l@ +lUx8
select top 10 * form table1 where 范围 m3Mo2};?
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 8(yZX4OH>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) VMry$
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 g"k1O
(select a from tableA ) except (select a from tableB) except (select a from tableC) Lk?%B)z
17、说明:随机取出10条数据 Y ^s_v_s
select top 10 * from tablename order by newid() qPh
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18、说明:随机选择记录 A1b</2
select newid() .hBq1p
19、说明:删除重复记录 'r&az BO
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) gN2$;hb?
20、说明:列出数据库里所有的表名 @J`o
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select name from sysobjects where type='U' &h(>jY7b;
21、说明:列出表里的所有的 DtXQLL*fl(
select name from syscolumns where id=object_id('TableName') l(c2 B
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。 "Di27Rq
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 bve_*7CEM
显示结果: 4*k>M+o/C4
type vender pcs +iS'$2)@
电脑 A 1
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电脑 A 1 9YpgzCx
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光盘 B 2 N$\'X<{
光盘 A 2 KpHt(>NR
手机 B 3 p~Tp=d)/
手机 C 3 =NHE_4/p
23、说明:初始化表table1 }tq
TRUNCATE TABLE table1 #xUX1(
24、说明:选择从10到15的记录 ``;.Oy6jS
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ;^XF;zpg
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三、技巧 ] !7%)
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?]*WVjskE
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 06ndW9>wD)
如: 0c2O'&$au
if @strWhere !='' W''%{A/'
begin ~m/nV81
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 'eyzH[l,(
end lk.]!K$}
else %7w=; ]ym
begin 6Zr_W#SE
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' OQlmzg
end l ga%U~
我们可以直接写成 OyI?P_0u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ` ,lm:x+(0
2、收缩数据库 o#"U8N%r
--重建索引 KCBA`N8
DBCC REINDEX q=I8W}Zi
DBCC INDEXDEFRAG TLcev*
--收缩数据和日志 #'DrgZ)W
DBCC SHRINKDB :n#8/'%1
DBCC SHRINKFILE uDtml$9rN
3、压缩数据库 nt 9LBea
dbcc shrinkdatabase(dbname) zd%n)jlwR
4、转移数据库给新用户以已存在用户权限 Lud[.>i
exec sp_change_users_login 'update_one','newname','oldname' f ZEyXb
go _xKIp>A
5、检查备份集 OD@k9I[
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hgYi ,e
6、修复数据库 0V RV.Ml
ALTER DATABASE [dvbbs] SET SINGLE_USER a&^HvXO(>(
GO +9^V9]{Vo
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Vy.gr4Cm
GO Mh=yIx</
ALTER DATABASE [dvbbs] SET MULTI_USER -yP|CZM
GO {yo{@pdX>
7、日志清除 L3/SIoqd
SET NOCOUNT ON k.."_4
DECLARE @LogicalFileName sysname, *F<Ar\f5
@MaxMinutes INT, (DLk+N4UHA
@NewSize INT :VkuK@Th`
USE tablename -- 要操作的数据库名 c
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >PYLk{q
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1bz%O2U-(
@NewSize = 1 -- 你想设定的日志文件的大小(M) qjBF]3%t%
-- Setup / initialize ?l> <?i
DECLARE @OriginalSize int Vn=K5nm
SELECT @OriginalSize = size X-,mNvz
FROM sysfiles \m xi8Z
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WHERE name = @LogicalFileName ugu|?z*dI
SELECT 'Original Size of ' + db_name() + ' LOG is ' + YW14X
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x?"+Or.h
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' dguN<yS-E
FROM sysfiles MyZ5~jnr\
WHERE name = @LogicalFileName <r>1W~bp.q
CREATE TABLE DummyTrans \CU-a`n
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, >g>L>{
@StartTime DATETIME, T1-.+&<
@TruncLog VARCHAR(255) =(==aP
SELECT @StartTime = GETDATE(), }5Zmc6S{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' kTW[)
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 1
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EXEC (@TruncLog) + L\Dh.Ir
-- Wrap the log if necessary. 'bQjJRq!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 67tB8X
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) h5o6G1ur
AND (@OriginalSize * 8 /1024) > @NewSize 7&hhKEA
BEGIN -- Outer loop. EXF|;@-"
SELECT @Counter = 0 zhC#<
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Hhzi(<e^
BEGIN -- update ixvF`S9
INSERT DummyTrans VALUES ('Fill Log') On~w`
DELETE DummyTrans gcA,u)z}R
SELECT @Counter = @Counter + 1 9Ai3p
END CcJ%;.V,T
EXEC (@TruncLog) r`\6+ Ntb.
END d)WGI
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + D7lRZb
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + TWeup6k
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' H5eGl|Z5]^
FROM sysfiles O>@ChQF
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans vNDf1B5z
SET NOCOUNT OFF oHPh2b0
8、说明:更改某个表 Yn_v'Os2
exec sp_changeobjectowner 'tablename','dbo' D[
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9、存储更改全部表 J1u&Ga
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1YtbV3
@OldOwner as NVARCHAR(128), uPVO!`N3
@NewOwner as NVARCHAR(128) 0{'m":D9
AS z.T>=C
DECLARE @Name as NVARCHAR(128) 0sP*ChY5S
DECLARE @Owner as NVARCHAR(128) N|2PW ~,
DECLARE @OwnerName as NVARCHAR(128) )i^S:2
DECLARE curObject CURSOR FOR adn2&7H
select 'Name' = name, D & Bdl5g
'Owner' = user_name(uid) zHX7%x,Cq
from sysobjects ;S?ei>Q
where user_name(uid)=@OldOwner 1>=]lMW
order by name mVd%sWD
OPEN curObject X/f?=U
FETCH NEXT FROM curObject INTO @Name, @Owner 8b:GyC5L
WHILE(@@FETCH_STATUS=0) M\A6;dz'
BEGIN `]I p`_{
if @Owner=@OldOwner _[pbfua
begin Ew )1O9f
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *5KDu$'(e
exec sp_changeobjectowner @OwnerName, @NewOwner !BjJ5m
end B'-n
^';
-- select @name,@NewOwner,@OldOwner U?xa^QVhj
FETCH NEXT FROM curObject INTO @Name, @Owner =/+f3
END n[gc`#7|{e
close curObject Ez+8B|0P
deallocate curObject NydF'N_1
GO yIu_DFq%
10、SQL SERVER中直接循环写入数据 a_\t(U
declare @i int Y#zHw<<E
set @i=1 RZ0+Uu/J
while @i<30 YS bS.tq
begin Q%QIr
insert into test (userid) values(@i) c=f;3N
set @i=@i+1 v=~+o[
end `PtfPt<{
小记存储过程中经常用到的本周,本月,本年函数 Kut@z>SK
Dateadd(wk,datediff(wk,0,getdate()),-1) v[4-?7-
Dateadd(wk,datediff(wk,0,getdate()),6) G.~Ffk
Dateadd(mm,datediff(mm,0,getdate()),0) SQ057V>'=
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,R}9n@JI^Y
Dateadd(yy,datediff(yy,0,getdate()),0) Aj*|r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) GGU>={D)
上面的SQL代码只是一个时间段 {#,?K
Dateadd(wk,datediff(wk,0,getdate()),-1) ]Jnrs
Dateadd(wk,datediff(wk,0,getdate()),6) E/hO0Ox6
就是表示本周时间段. Y^QG\6q
下面的SQL的条件部分,就是查询时间段在本周范围内的: 3~\,VO''
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) @6Z6@Pq(xQ
而在存储过程中 b"y4-KV
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .wPI%5D
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {XH3zMk[