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。 {EB;h\C
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一、基础 B"1c
1、说明:创建数据库 SJn;{X>)q
CREATE DATABASE database-name /T0F"e)Ci
2、说明:删除数据库 IL#"~D?
drop database dbname @k,#L`3^
3、说明:备份sql server 2*;~S44
--- 创建 备份数据的 device k<CJ{u0<
USE master |6sp/38#p
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' $w`xvX
--- 开始 备份 Tztu}t]N
BACKUP DATABASE pubs TO testBack '}53f2%gKa
4、说明:创建新表 )l C)@H}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !C':
根据已有的表创建新表: _7Ju
A:create table tab_new like tab_old (使用旧表创建新表) 99e.n0
B:create table tab_new as select col1,col2... from tab_old definition only S6Q
5、说明:删除新表 e5ZX
drop table tabname C!<Ou6}!b
6、说明:增加一个列 t6"%3#s
Alter table tabname add column col type %HhnSi1K
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。 l` lk-nb
7、说明:添加主键: Alter table tabname add primary key(col) RB7tmJc
说明:删除主键: Alter table tabname drop primary key(col) cKca;SNql1
8、说明:创建索引:create [unique] index idxname on tabname(col....) k_#ak%m/
删除索引:drop index idxname $Vg>I>i
注:索引是不可更改的,想更改必须删除重新建。 >C>.\
9、说明:创建视图:create view viewname as select statement _}Ac n$
删除视图:drop view viewname mp1@|*Sn
10、说明:几个简单的基本的sql语句 DN>[\hg
选择:select * from table1 where 范围 nfbR
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插入:insert into table1(field1,field2) values(value1,value2) J/y83@
删除:delete from table1 where 范围 ,q`\\d
更新:update table1 set field1=value1 where 范围 Mq156TL
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D0-3eV-
排序:select * from table1 order by field1,field2 [desc] zFfr.g;L
总数:select count as totalcount from table1 AlaW=leTe
求和:select sum(field1) as sumvalue from table1 Cv.C;H
平均:select avg(field1) as avgvalue from table1 e8a+2.!&\
最大:select max(field1) as maxvalue from table1 Mk 6(UXY
最小:select min(field1) as minvalue from table1 2*& ^v
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11、说明:几个高级查询运算词 Naf0)3q>!
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A: UNION 运算符 9s
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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。 dFB]~QEK
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。 D;*SnU(9L
C: INTERSECT 运算符 m=:9+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。 0Th&iA4
注:使用运算词的几个查询结果行必须是一致的。 k1~&x$G
12、说明:使用外连接 VscE ^'+
A、left outer join: CY5Z{qiX
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 IHac:=*Q
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ""G'rN_=Bi
B:right outer join: U?Zq6_M&
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 (y~TL*B
C:full outer join: JX;G<lev
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 *w\W/ Y
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二、提升 N=}A Z{$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Xc-'Y"}|`t
法一:select * into b from a where 1<>1 kgP0x-Ap
法二:select top 0 * into b from a L L~%f
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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) UB@+ck
insert into b(a, b, c) select d,e,f from b; 4Z&lYLq;
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) FcU SE
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ^\=`edN 0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^6V[=!& H
4、说明:子查询(表名1:a 表名2:b) [RhO$c$[\
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) g}cq K
5、说明:显示文章、提交人和最后回复时间 }&J q}j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~B?y{
6、说明:外连接查询(表名1:a 表名2:b) ^hM4j{|&M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l'_r:b
7、说明:在线视图查询(表名1:a ) @qAS*3j
select * from (SELECT a,b,c FROM a) T where t.a > 1; }Zn}
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 S4z;7z(8+
select * from table1 where time between time1 and time2 c-5)QF) z
select a,b,c, from table1 where a not between 数值1 and 数值2 +=</&Tm
9、说明:in 的使用方法 ?0SJfh
select * from table1 where a [not] in ('值1','值2','值4','值6') VpDbHAg
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {JMVV_}n
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) n{mfn*r.
11、说明:四表联查问题: NZ0;5xGR
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 ..... 0aB;p7~&
12、说明:日程安排提前五分钟提醒 rg!r[1c
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0x@
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13、说明:一条sql 语句搞定数据库分页 `d}2O%P
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 oUU1+F-
14、说明:前10条记录 ^<2p~h0
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select top 10 * form table1 where 范围 '~=SzO
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/MmmT
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1mG-}
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&PXH
(select a from tableA ) except (select a from tableB) except (select a from tableC) eeB{c.#
17、说明:随机取出10条数据 tGa8W
select top 10 * from tablename order by newid() zK@@p+n_#.
18、说明:随机选择记录 ?6WY:Zec@
select newid() [{,1=AB
19、说明:删除重复记录 L4nYXW0y
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) T_4/C2
20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' S<Xf>-8w
21、说明:列出表里的所有的 }pkzH'$HJ
select name from syscolumns where id=object_id('TableName') ( a#BV}=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 }BP;1y6-r
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 4.t-i5
显示结果: 9\7en%( M
type vender pcs C?eH]hkZ3
电脑 A 1 N~'c_l
电脑 A 1 ;:NJCu G
光盘 B 2 Y}wyw8g/
光盘 A 2 =UWI9M*sz
手机 B 3 4o[{>gW
手机 C 3 H qx-;F~0
23、说明:初始化表table1 F:S}w
TRUNCATE TABLE table1 k8zI(5.>
24、说明:选择从10到15的记录 UkFC~17P
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc oEpFuWp%A
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三、技巧 #%O0[kd
1、1=1,1=2的使用,在SQL语句组合时用的较多 cw
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, jmG~Un M
如: LrpM\}t
if @strWhere !='' TB31-
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begin }0y"F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere do'GlU oMC
end FGzwhgy
else G 01ON0
begin P]C<U aW'!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' pd$[8Rmj_
end ^S; -fYW2
我们可以直接写成 xyXa .
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }^\oCR@
2、收缩数据库 I7]8Y=xf
--重建索引 , W?VhO
DBCC REINDEX j1<Yg,_.p
DBCC INDEXDEFRAG wC'Szni
--收缩数据和日志 J<lW<:!3]
DBCC SHRINKDB Kc\fu3Q
DBCC SHRINKFILE RxQ *
3、压缩数据库 {{!-Gr
dbcc shrinkdatabase(dbname) :Zlwy-[
4、转移数据库给新用户以已存在用户权限 Q/Rqa5LI:
exec sp_change_users_login 'update_one','newname','oldname' %BQ`MZ
go uXiN~j &Be
5、检查备份集 6aj!Q*(WT
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' kq-) ^,{y
6、修复数据库 \w8\1~#
ALTER DATABASE [dvbbs] SET SINGLE_USER N2o7%gJw
GO #\ErY3k 6&
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK yf,z$CR
GO cWm$;`Q#\
ALTER DATABASE [dvbbs] SET MULTI_USER P$,Ke<
GO vP,n(reM
7、日志清除 5bb(/YtFy
SET NOCOUNT ON ~$J2g
DECLARE @LogicalFileName sysname, "r2 r
@MaxMinutes INT, ?V=CB,^
@NewSize INT LR3*G7
USE tablename -- 要操作的数据库名 1Z&(6cDY8M
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 XK vi=0B
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \{D"
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@NewSize = 1 -- 你想设定的日志文件的大小(M) zT{VE+=
-- Setup / initialize !5N.B|Nt
DECLARE @OriginalSize int
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SELECT @OriginalSize = size Uw:"n]G]D?
FROM sysfiles n&!-9:0
WHERE name = @LogicalFileName G+m }MOQP7
SELECT 'Original Size of ' + db_name() + ' LOG is ' + hqdDm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + nr3==21Om4
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' moE2G?R
FROM sysfiles !@"OB~
WHERE name = @LogicalFileName Alq(QDs
CREATE TABLE DummyTrans 1E$|~
(DummyColumn char (8000) not null) H;"4C8K7
DECLARE @Counter INT, V.2_i*
@StartTime DATETIME, [-x7_=E#
@TruncLog VARCHAR(255) 47B&s
SELECT @StartTime = GETDATE(), |l!aB(NW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' vKR[&K{Z|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) *K;~!P
EXEC (@TruncLog) Qg/rRiV
-- Wrap the log if necessary. E(|>Ddv B&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w2J<WC+_<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8b=_Y;
AND (@OriginalSize * 8 /1024) > @NewSize ##ANrG l
BEGIN -- Outer loop. Q59W#e)
SELECT @Counter = 0 T8NxJmYqB
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ;n},"&
BEGIN -- update T]$U""
INSERT DummyTrans VALUES ('Fill Log') `F6C-
DELETE DummyTrans M3Kfd
SELECT @Counter = @Counter + 1 %|4UsWZ
END WF"k[2
EXEC (@TruncLog) V43H/hl
END hv+zGID7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + -K$)DvV^(E
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :hA#m[
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' yLcEX
FROM sysfiles dqAw5[qMJ
WHERE name = @LogicalFileName !&\INl-Z
DROP TABLE DummyTrans w*Ihk)
SET NOCOUNT OFF 2Rz
8、说明:更改某个表 j| Q-*]V
exec sp_changeobjectowner 'tablename','dbo' <-0]i_4sK
9、存储更改全部表 @ .KGfNu
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?fS9J
@OldOwner as NVARCHAR(128), .p$(ZH =~
@NewOwner as NVARCHAR(128) mVmGg,
AS oXS}IL
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DECLARE @Name as NVARCHAR(128) 9>$p
DECLARE @Owner as NVARCHAR(128) v8DC21pb
DECLARE @OwnerName as NVARCHAR(128) B1Oq!k
DECLARE curObject CURSOR FOR 'ig'cRD6N
select 'Name' = name, CQ2jP
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'Owner' = user_name(uid) <6=c,y
from sysobjects Vz[C=_m
where user_name(uid)=@OldOwner O9p|a%o
order by name H:\k}*w
OPEN curObject Ct|A:/z(
FETCH NEXT FROM curObject INTO @Name, @Owner F<w/PMb
WHILE(@@FETCH_STATUS=0) jq-_4}w?C
BEGIN LIdF 0
if @Owner=@OldOwner |Ds=)S"
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begin ,2)6s\]/b
set @OwnerName = @OldOwner + '.' + rtrim(@Name) IO> yIU[
exec sp_changeobjectowner @OwnerName, @NewOwner c"xK`%e
end q,6DEz
-- select @name,@NewOwner,@OldOwner D3A/l
FETCH NEXT FROM curObject INTO @Name, @Owner Cls%M5MH
END %K
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close curObject iyog`s c
deallocate curObject Xx(T">]vJ
GO .[ mRM
10、SQL SERVER中直接循环写入数据 V1JIht>Opo
declare @i int ]s748+
set @i=1 }d }lR
while @i<30 hpJ-r
begin #o2[hibq
insert into test (userid) values(@i) D,ln)["xm
set @i=@i+1 W}1
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end fxIf|9Qi`
小记存储过程中经常用到的本周,本月,本年函数 w`=\5Oa .G
Dateadd(wk,datediff(wk,0,getdate()),-1) 2Hv+W-6v
Dateadd(wk,datediff(wk,0,getdate()),6) 3[f):
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Dateadd(mm,datediff(mm,0,getdate()),0) 3yXY.>'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ei{eTp4HpV
Dateadd(yy,datediff(yy,0,getdate()),0) CWS4lx
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4H<lm*!^
上面的SQL代码只是一个时间段 ri.I pRe
Dateadd(wk,datediff(wk,0,getdate()),-1) V470C@
Dateadd(wk,datediff(wk,0,getdate()),6) Qw)c$93
就是表示本周时间段. as_PoCoss
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~3 bPIg7D
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $tS}LN_!
而在存储过程中 tRfo$4#NY
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) kSh( u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `~`k_7t.