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。 J@HtoTDO3
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一、基础 #?aPisV
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1、说明:创建数据库 O_muD\
CREATE DATABASE database-name a8e6H30Sm
2、说明:删除数据库 T9E+\D
drop database dbname ]KKS"0a
3、说明:备份sql server c(f
--- 创建 备份数据的 device T?CdZc.
USE master F`9xVnK=
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' lBLARz&c#
--- 开始 备份 Af~$TyX
BACKUP DATABASE pubs TO testBack t:x\kp
4、说明:创建新表 b;B%q$sntC
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~~/|dh5
根据已有的表创建新表: 9IdA%RM~mH
A:create table tab_new like tab_old (使用旧表创建新表) \$~|ZwV{
B:create table tab_new as select col1,col2... from tab_old definition only $t'MSlF
5、说明:删除新表 !7O+ogL
drop table tabname T@H^BGs
6、说明:增加一个列 vFzRg5lH
Alter table tabname add column col type ^qvZXb
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。 !I{0 _b{
7、说明:添加主键: Alter table tabname add primary key(col) p}z<Fdu0
说明:删除主键: Alter table tabname drop primary key(col) hn7#
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8、说明:创建索引:create [unique] index idxname on tabname(col....) ~f&E7su-6+
删除索引:drop index idxname xf\ C|@i
注:索引是不可更改的,想更改必须删除重新建。 e9Wa<i8
9、说明:创建视图:create view viewname as select statement hlvK5Z
删除视图:drop view viewname +5g_KS
10、说明:几个简单的基本的sql语句 P-9)38`5
选择:select * from table1 where 范围 \"w"$9o6
插入:insert into table1(field1,field2) values(value1,value2) T$)^gHS
删除:delete from table1 where 范围 pGP7nw_g
更新:update table1 set field1=value1 where 范围 jh?H.;**
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Y#ap*
排序:select * from table1 order by field1,field2 [desc] _P#|IAq*
总数:select count as totalcount from table1 !]A
求和:select sum(field1) as sumvalue from table1 %OL$57Ia
平均:select avg(field1) as avgvalue from table1 ^&9zw\x;z
最大:select max(field1) as maxvalue from table1 k{R>
最小:select min(field1) as minvalue from table1 60^`JVGWH
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11、说明:几个高级查询运算词 6IN
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A: UNION 运算符 /wGM#sFH
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。 '|6]_
B: EXCEPT 运算符 @(EAq<5{
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。 TNT4<5Ol6
C: INTERSECT 运算符 F/,NDZN
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。 wyH[x!QX
注:使用运算词的几个查询结果行必须是一致的。 9R!atPz9
12、说明:使用外连接 1fp?
A、left outer join: 7y'RFD9@{
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。 NR$3%0 nC6
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W 8<&gh+
B:right outer join: kP=eW_0D
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 H5/6TX72N
C:full outer join: OR P\b
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 XW2b| %T
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二、提升 <)C#_w)-
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) np|Sy;:
法一:select * into b from a where 1<>1 @Myo'{3vF
法二:select top 0 * into b from a YH}'s>xZz
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) nUaJzPl
insert into b(a, b, c) select d,e,f from b; '&P%C" 5
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) g i3F`
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 rET\n(AJ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. x;O[c3I
4、说明:子查询(表名1:a 表名2:b) <q58uuK
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ^`i#$
5、说明:显示文章、提交人和最后回复时间 ^x ]r`b
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (q/e1L-S
6、说明:外连接查询(表名1:a 表名2:b) B9 _X;c
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !NK1MU?T)
7、说明:在线视图查询(表名1:a ) ~Py`P'+
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;DQ ZT
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 A7{\</Z
select * from table1 where time between time1 and time2 P_^ +A
select a,b,c, from table1 where a not between 数值1 and 数值2 ~f2z]JLr:
9、说明:in 的使用方法 w?PkO p
select * from table1 where a [not] in ('值1','值2','值4','值6') Qab>|eSm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 M/B_#yK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RXMISt3+{y
11、说明:四表联查问题: /aCc17>2V{
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 ..... 8L=HW G!1
12、说明:日程安排提前五分钟提醒 YR\fa Vk
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 l
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13、说明:一条sql 语句搞定数据库分页 olB.*#gA
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+iiSTJEe
14、说明:前10条记录 .D"m@~j7
select top 10 * form table1 where 范围 5+4IN5o]=
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.) >a<.mU|#
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) LG9+GszX 2
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 VcE:G#]5
(select a from tableA ) except (select a from tableB) except (select a from tableC) JJ-( Sl
17、说明:随机取出10条数据 Uk wP
select top 10 * from tablename order by newid() *}qWj_RT
18、说明:随机选择记录 V;VHv=9`o
select newid() 3Y4?CM&0v
19、说明:删除重复记录 5+0gR
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) LtF,kAIt7v
20、说明:列出数据库里所有的表名 #FLb*%Nr
select name from sysobjects where type='U' @}u*|P*
21、说明:列出表里的所有的 h%na>G
select name from syscolumns where id=object_id('TableName') d A}-]
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。 x
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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 Ys9[5@7
显示结果: caR<Kb:;*
type vender pcs s*KhF'fN
电脑 A 1 qCC.^8
电脑 A 1 hg]]Ok~cAs
光盘 B 2 5J.bD)yrP
光盘 A 2 #6aW9GO
手机 B 3 4}baSV
手机 C 3 ?T8}K>a
23、说明:初始化表table1 |)DGkOtd
TRUNCATE TABLE table1 HXC ;Np
24、说明:选择从10到15的记录 ITX a&5D
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G^|:N[>B
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三、技巧 V*;(kEqj
1、1=1,1=2的使用,在SQL语句组合时用的较多 GT.,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;6
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如: ea2ayT
if @strWhere !='' r EE1sy/#
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )gUR@V>e2
end %g$o/A$
else \ A#41
begin {%5eMyF#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?3`UbN:
end :K,i\
我们可以直接写成 T@B/xAq5!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /N10
2、收缩数据库 x_Y!5yg
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--重建索引 H [\o RId
DBCC REINDEX oG?Xk%7&\
DBCC INDEXDEFRAG 3BUSv#w{i
--收缩数据和日志 @+2=g WH
DBCC SHRINKDB q-2Bt,Y
DBCC SHRINKFILE ]IQ&>z}<
3、压缩数据库 yjX9oxhtL
dbcc shrinkdatabase(dbname) K&]G3W%V
4、转移数据库给新用户以已存在用户权限 Hyl%mJ
exec sp_change_users_login 'update_one','newname','oldname' .p3,O6y2(F
go 3BJ0S.TF
5、检查备份集 Xza(k
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (*'f+R`$
6、修复数据库 &-6Gc;f8
ALTER DATABASE [dvbbs] SET SINGLE_USER *I.f1lz%*
GO ORw,)l
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `cUl7 'j
GO AM \'RHL
ALTER DATABASE [dvbbs] SET MULTI_USER cd_yzpL@}J
GO :J@gmY:C
7、日志清除 +.[ <%
SET NOCOUNT ON >uB#&Q
DECLARE @LogicalFileName sysname, ]y'>=a|T
@MaxMinutes INT, ^A/k)x6
@NewSize INT g3/W=~r
USE tablename -- 要操作的数据库名 83\pZ1>)_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3z?> j]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. B%b4v
@NewSize = 1 -- 你想设定的日志文件的大小(M) u'DRN,h+
-- Setup / initialize D?_Zl;bQ'^
DECLARE @OriginalSize int }@+0/W?\.
SELECT @OriginalSize = size YnAm{YyI
FROM sysfiles 5coyr`7mP
WHERE name = @LogicalFileName $k%2J9O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 7(8;to6(
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <{cQM$#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' _C?hHWSf"
FROM sysfiles 9~XAq^e
WHERE name = @LogicalFileName hx %v+/
CREATE TABLE DummyTrans Rtl"Ub@HV
(DummyColumn char (8000) not null) m}t`FsB.
DECLARE @Counter INT, WX?IYQ+
@StartTime DATETIME, k$R-#f;
@TruncLog VARCHAR(255) KwSqKI7]0
SELECT @StartTime = GETDATE(), nRS} }6Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) a~}OZ&PG
EXEC (@TruncLog) oW*16>IN9l
-- Wrap the log if necessary. 0R'?~`aTt
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6SkaH<-&K
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) d.d/<
AND (@OriginalSize * 8 /1024) > @NewSize vJ[^K
BEGIN -- Outer loop. $ @`V
SELECT @Counter = 0 .j0$J\:i
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) aP+X}r
BEGIN -- update Be2DN5)
INSERT DummyTrans VALUES ('Fill Log') [D4SW#
DELETE DummyTrans "$^ ~!1~
SELECT @Counter = @Counter + 1 %_W)~Pv{+
END u cW-I;"
EXEC (@TruncLog) *fS"ym@
END 3$>1FoSk
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9IfmW^0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /]Md~=yNp
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' | rtD.,m
FROM sysfiles !ons]^km
WHERE name = @LogicalFileName MaQqs=
DROP TABLE DummyTrans ,f'CD{ E
SET NOCOUNT OFF 9F;>W ET
8、说明:更改某个表 6}Ci>_i4#
exec sp_changeobjectowner 'tablename','dbo' ag[wdoj
9、存储更改全部表 H=vUYz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "_NN3lD)X
@OldOwner as NVARCHAR(128), R"t,xM
@NewOwner as NVARCHAR(128) WO>nIo5Y
AS xr Jg\to{i
DECLARE @Name as NVARCHAR(128) @,my7?::oM
DECLARE @Owner as NVARCHAR(128) CxW>~O:
DECLARE @OwnerName as NVARCHAR(128) ^%{7}g&$u
DECLARE curObject CURSOR FOR T_5H&;a
select 'Name' = name, D.u{~
'Owner' = user_name(uid) mL{6L?
from sysobjects "&?kC2Y|
where user_name(uid)=@OldOwner ^A&1^B
order by name `e&Suyf4B
OPEN curObject G}raA%
FETCH NEXT FROM curObject INTO @Name, @Owner Z0", !6nS
WHILE(@@FETCH_STATUS=0) L^?qOylu
BEGIN +lcbi
if @Owner=@OldOwner 4p;`C
begin -- 95Jz
set @OwnerName = @OldOwner + '.' + rtrim(@Name) #r\4sVg
exec sp_changeobjectowner @OwnerName, @NewOwner .|fHy
end 4!yzsPJL
-- select @name,@NewOwner,@OldOwner `mJ6K&t$<
FETCH NEXT FROM curObject INTO @Name, @Owner j>" @,B g*
END J<h$
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close curObject `l[c_%Bm
deallocate curObject .?sx&2R2
GO SZ'R59Ee<
10、SQL SERVER中直接循环写入数据 flbd0NB
declare @i int $G@5qxcV
set @i=1 Wt-GjxGi
while @i<30 2uW;
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begin iz PDd{[
insert into test (userid) values(@i) (iX+{a%"
set @i=@i+1 Y\8)OBZ
end Om2d.7S
小记存储过程中经常用到的本周,本月,本年函数 ?NsW|w_
Dateadd(wk,datediff(wk,0,getdate()),-1) ZKTz
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Dateadd(wk,datediff(wk,0,getdate()),6) ;h
Dateadd(mm,datediff(mm,0,getdate()),0) ;dgp+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0GCEqQy8
Dateadd(yy,datediff(yy,0,getdate()),0) CkQ3#L <2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >0TxUc_va
上面的SQL代码只是一个时间段 Feq]U?
Dateadd(wk,datediff(wk,0,getdate()),-1) o3P${Rq
Dateadd(wk,datediff(wk,0,getdate()),6) h3
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就是表示本周时间段. ?%[@Qb=2
下面的SQL的条件部分,就是查询时间段在本周范围内的: '7@zGk##(
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) `b7t4d*
而在存储过程中 Iit;F
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Eo]xNn/g
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U$z-e/