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)4hL
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一、基础 9.&mz}q
1、说明:创建数据库 CWlW/>yF
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CREATE DATABASE database-name o\6iq
2、说明:删除数据库 L"vj0@n'0
drop database dbname E5UcZ7
3、说明:备份sql server <1@
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--- 创建 备份数据的 device it1/3y
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USE master {1~T]5
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' usOx=^?=
--- 开始 备份 \##5O7/1
BACKUP DATABASE pubs TO testBack &[j]Bp?
4、说明:创建新表 *YvRNHP
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) pn\V+Rg'
根据已有的表创建新表: 1`-r#-MGG
A:create table tab_new like tab_old (使用旧表创建新表) u^4h&fL
B:create table tab_new as select col1,col2... from tab_old definition only lTz6"/
5、说明:删除新表 vV^dm)?
drop table tabname Dp!zk}f|
6、说明:增加一个列 {gU&%j
Alter table tabname add column col type ;dQAV\
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。 #H5=a6E+q
7、说明:添加主键: Alter table tabname add primary key(col) -]XP2}#d
说明:删除主键: Alter table tabname drop primary key(col) r:9gf?(&
8、说明:创建索引:create [unique] index idxname on tabname(col....) y=H@6$2EQ
删除索引:drop index idxname >n$!<
注:索引是不可更改的,想更改必须删除重新建。 &mkpJF/
9、说明:创建视图:create view viewname as select statement %Kto.Xq
删除视图:drop view viewname `fS^
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10、说明:几个简单的基本的sql语句 n&!+wcJ;Yt
选择:select * from table1 where 范围 SSmHEy*r)
插入:insert into table1(field1,field2) values(value1,value2) JP'=
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删除:delete from table1 where 范围 ]vo_gKZ
更新:update table1 set field1=value1 where 范围 Gr)-5qh
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9_huI'"p
排序:select * from table1 order by field1,field2 [desc] m{(+6-8|m
总数:select count as totalcount from table1 NP_?f%(
求和:select sum(field1) as sumvalue from table1 K
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平均:select avg(field1) as avgvalue from table1 1;wb(DN*c
最大:select max(field1) as maxvalue from table1 ;n*J$B
最小:select min(field1) as minvalue from table1 =2 jhII
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11、说明:几个高级查询运算词 wk[
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A: UNION 运算符 -cfx2;68
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 MCYl{uH!
B: EXCEPT 运算符 JwP:2-o
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Yx%bn?%;&
C: INTERSECT 运算符 !B^K[2`)N
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 1"]P`SY$r
注:使用运算词的几个查询结果行必须是一致的。 wahZK~,EaY
12、说明:使用外连接 YQVcECj
A、left outer join: K=\&+at1
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。 Ijedo/
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 QK <\kVZ8
B:right outer join: &drFQ|
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。 LWmB,
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C:full outer join: KoHGweKl#
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。 rt!r2dq"
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二、提升 u"+}I,'L
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) m5-9yQ=.
法一:select * into b from a where 1<>1 ]gP5f @`
法二:select top 0 * into b from a J^zi2jtV
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 2{oThef[O
insert into b(a, b, c) select d,e,f from b; tT5pggml
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) *g$i5!yM'
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 :uK
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. d3^7ag%
4、说明:子查询(表名1:a 表名2:b) YfDWM7x7,
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) ,XB%\[pKe
5、说明:显示文章、提交人和最后回复时间 C`K^L=8`{
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b jP=Hf=:$
6、说明:外连接查询(表名1:a 表名2:b) qd6fU^)i
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c J YmAn?o-
7、说明:在线视图查询(表名1:a ) GyC)EFd
select * from (SELECT a,b,c FROM a) T where t.a > 1; +5X DF
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 \l,rpVv5m
select * from table1 where time between time1 and time2 5%i:4sMx
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select a,b,c, from table1 where a not between 数值1 and 数值2 AW8'RfC.
9、说明:in 的使用方法 p/olCmHD)
select * from table1 where a [not] in ('值1','值2','值4','值6') X0uJNHO
10、说明:两张关联表,删除主表中已经在副表中没有的信息 yyP-=Lhmo=
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) iRw&49
11、说明:四表联查问题: r>|-2}{N/
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 ..... @;)PSp*j
12、说明:日程安排提前五分钟提醒 ;y1Q6eN
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 =8JB8ZFP
13、说明:一条sql 语句搞定数据库分页 p2 ! FcFi
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 O)#U ^
14、说明:前10条记录 k`VM2+9h'^
select top 10 * form table1 where 范围 $c9k*3{<+A
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Tlsa%pn
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) A
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 mP^SS
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(select a from tableA ) except (select a from tableB) except (select a from tableC) Pe ~c
17、说明:随机取出10条数据 1ThqqB
select top 10 * from tablename order by newid() 97`WMs
18、说明:随机选择记录 JUt7En;XE
select newid() M+Uyb7
19、说明:删除重复记录 Mi0sC24b|
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) K-Mc6
20、说明:列出数据库里所有的表名 aMwB>bt
select name from sysobjects where type='U' i[nF.I5*f
21、说明:列出表里的所有的 X0$@Ik
select name from syscolumns where id=object_id('TableName') kgW @RD|
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。 uA~slS
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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 B3
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显示结果: MC!ZX)mF
type vender pcs w *!wQ,o
电脑 A 1 PLR0#).n
电脑 A 1 0b-?q&*_
光盘 B 2 [r-}bp'Gp
光盘 A 2 =$^MQ\S0p
手机 B 3 =1hr2R(V
手机 C 3 M\2"gT-LV
23、说明:初始化表table1 'Pd(\$ZY
TRUNCATE TABLE table1 pGGmA;TC1
24、说明:选择从10到15的记录 p,!$/Q+l
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc eV!L^>>>
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三、技巧 $:bih4@>
1、1=1,1=2的使用,在SQL语句组合时用的较多 W`)<vGn=Y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, (?i[jO||B
如: EU+cca|qS9
if @strWhere !='' {|<"C?
begin lP_db&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere AHbZQulC
end ;)hw%Z]Jj$
else dQ:cYNm
begin =JO^XwUOo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @F5f"8!.\
end '\7G@g?UZ
我们可以直接写成 Lxe^v/LsT
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere I-@?guZ r
2、收缩数据库 6(V
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--重建索引 YZwaD b
DBCC REINDEX j;nb?;
DBCC INDEXDEFRAG /DFV$+9
--收缩数据和日志 <PD?f/4 /
DBCC SHRINKDB 3=.Y,ENM;
DBCC SHRINKFILE 5er@)p_
3、压缩数据库 8*a),
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dbcc shrinkdatabase(dbname) Z|m`7xeCy
4、转移数据库给新用户以已存在用户权限 1%~ZRmd e
exec sp_change_users_login 'update_one','newname','oldname' -*ELLY[
go vT{ kL
5、检查备份集 !PUZWO
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' rNN
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6、修复数据库 Kuw^qX"
ALTER DATABASE [dvbbs] SET SINGLE_USER #2p#VQh
GO t%VDRZo7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK a:rX9-**
GO d j5hv~
ALTER DATABASE [dvbbs] SET MULTI_USER J ++v@4Z
GO jA(vTR.`
7、日志清除 0BU=)Swku
SET NOCOUNT ON @R6 ttx
DECLARE @LogicalFileName sysname, L=!of{4Z(}
@MaxMinutes INT, 3z =^(Y
@NewSize INT |i%2%V#
USE tablename -- 要操作的数据库名 @_ygnNn4R
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 u dk.zk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. :<S<f%
@NewSize = 1 -- 你想设定的日志文件的大小(M) W[''Cc.
-- Setup / initialize !7p}C-RZp
DECLARE @OriginalSize int |F$BvCg
SELECT @OriginalSize = size ;/O#4]2*
FROM sysfiles 8F5|EpB9M
WHERE name = @LogicalFileName 'xK.UI
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Q(7ob}+jQ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @E9" Zv-$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' PO-"M)M
FROM sysfiles 5p"BD'^:
WHERE name = @LogicalFileName Zk-~ar
CREATE TABLE DummyTrans hlJpElYf
(DummyColumn char (8000) not null) IzLF'F
DECLARE @Counter INT, -6~' cm
@StartTime DATETIME, (nSml,gU
@TruncLog VARCHAR(255) $9!D\N,}]C
SELECT @StartTime = GETDATE(), XVVD 0^ Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' eTay>G
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Bik*b)9y2
EXEC (@TruncLog) b0<o
-- Wrap the log if necessary. r4}*l7Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0S/'
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) `u'bRp
AND (@OriginalSize * 8 /1024) > @NewSize MHj,<|8Q
BEGIN -- Outer loop. \fWW'
SELECT @Counter = 0 TYns~X_PR
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) L5fuM]G`
BEGIN -- update +JyUe
INSERT DummyTrans VALUES ('Fill Log') U
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DELETE DummyTrans G%lu28}D
SELECT @Counter = @Counter + 1 4$6T+i2E
END Z=S>0|`R
EXEC (@TruncLog) "hz\Z0zg2
END njPPztv/@
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6i@\5}m=
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9SQ4cv*2
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q%YV$$c
FROM sysfiles eet Q}]
WHERE name = @LogicalFileName C#pZw[
DROP TABLE DummyTrans )~)*=u/
SET NOCOUNT OFF .4y>QN#VL
8、说明:更改某个表 |J5 =J
exec sp_changeobjectowner 'tablename','dbo' 8|?LN8rp
9、存储更改全部表 266oTER]v:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E; $+f
@OldOwner as NVARCHAR(128), eJCjJ)
@NewOwner as NVARCHAR(128) una%[jTc
AS y@V_g'
DECLARE @Name as NVARCHAR(128) siDh="{s
DECLARE @Owner as NVARCHAR(128) 13'vH]S$M
DECLARE @OwnerName as NVARCHAR(128) $
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DECLARE curObject CURSOR FOR OFkNl}D
select 'Name' = name, YcX/{L[9o
'Owner' = user_name(uid) -Y 9SngxM
from sysobjects V%0I%\0Y
where user_name(uid)=@OldOwner IeX^4rc(
order by name *u6Y8IL1
OPEN curObject (h-*_a}F4
FETCH NEXT FROM curObject INTO @Name, @Owner ,Tagj`@bHc
WHILE(@@FETCH_STATUS=0) oB1>x^
BEGIN gR^>3n'
if @Owner=@OldOwner ~ (On|h
begin LjFqZrH
set @OwnerName = @OldOwner + '.' + rtrim(@Name) t`'iU$:1f
exec sp_changeobjectowner @OwnerName, @NewOwner 4\ c,)U}
end owpWz6k7
-- select @name,@NewOwner,@OldOwner E\8
FETCH NEXT FROM curObject INTO @Name, @Owner b,TiMf9},h
END 1SIq[1
close curObject r,P1^ uHx
deallocate curObject LA3<=R]
GO )D-c]+yt
10、SQL SERVER中直接循环写入数据 _?voU
declare @i int J
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set @i=1 &hIRd,1#
while @i<30 M6r^L6$N
begin /.Nov
insert into test (userid) values(@i) <N,)G
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set @i=@i+1 DHC+C4
end RR;AJ8wd
小记存储过程中经常用到的本周,本月,本年函数 (m[bWdANnW
Dateadd(wk,datediff(wk,0,getdate()),-1) M@1r:4CoKH
Dateadd(wk,datediff(wk,0,getdate()),6) vR6Bn
Dateadd(mm,datediff(mm,0,getdate()),0) k^ F@X
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 2f`nMW
Dateadd(yy,datediff(yy,0,getdate()),0) ]j~"mFAP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %%ae^*[!n
上面的SQL代码只是一个时间段 :1q4"tv|
Dateadd(wk,datediff(wk,0,getdate()),-1) q-ES6R
Dateadd(wk,datediff(wk,0,getdate()),6) W,@
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就是表示本周时间段. &5{xXWJK
下面的SQL的条件部分,就是查询时间段在本周范围内的: mV^Zy
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) dBV7Te4L
而在存储过程中 F(#rQ_z]
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ZPN
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) i|)Su4Dw