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。 P'<D0
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一、基础 =`W#R
1、说明:创建数据库 X7Z=@d(
CREATE DATABASE database-name lVra&5
2、说明:删除数据库 p/WE[8U
drop database dbname N*NGC!p`N
3、说明:备份sql server yZyB.wT
--- 创建 备份数据的 device oH>G3n|U^
USE master _p^&]eQ+k#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' agUdPl$e\
--- 开始 备份 eX3|<Bf
BACKUP DATABASE pubs TO testBack 1k dQh&~G
4、说明:创建新表 <#%kmYSL
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 4E0 Y=
根据已有的表创建新表: l37)
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A:create table tab_new like tab_old (使用旧表创建新表) 5kdh!qy[$,
B:create table tab_new as select col1,col2... from tab_old definition only qw35LyL
5、说明:删除新表 tuIQiWHbM
drop table tabname <#>{7" }
6、说明:增加一个列 %Xjg/5G -
Alter table tabname add column col type +txHj(Y`
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。 U%u%_{-
7、说明:添加主键: Alter table tabname add primary key(col) Fsi;[be$A
说明:删除主键: Alter table tabname drop primary key(col) y??^[ sB
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^"!)p2=
删除索引:drop index idxname ]7:*A7/!.
注:索引是不可更改的,想更改必须删除重新建。 t=BXuFiu
9、说明:创建视图:create view viewname as select statement :9Mqwgk,;3
删除视图:drop view viewname -*AUCns#
10、说明:几个简单的基本的sql语句 !'f.g|a
选择:select * from table1 where 范围 ,%4~ulKMn
插入:insert into table1(field1,field2) values(value1,value2) W)p?cK`
删除:delete from table1 where 范围 <4,LTB]9-
更新:update table1 set field1=value1 where 范围 sHn-#SGm
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! gl>%ADOB@
排序:select * from table1 order by field1,field2 [desc] ;{:bq`56f
总数:select count as totalcount from table1 </-aG[Fi
求和:select sum(field1) as sumvalue from table1 YX{c06BHs
平均:select avg(field1) as avgvalue from table1 #.W^7}H
最大:select max(field1) as maxvalue from table1 ]3&BLq
最小:select min(field1) as minvalue from table1 /P
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11、说明:几个高级查询运算词 c6~<vV'}
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A: UNION 运算符 ka?EXF:
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 bM1b
B: EXCEPT 运算符 u.9syr
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。 "*JyNwf
C: INTERSECT 运算符 i=AQ1X\s
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。 a*bAf'=
注:使用运算词的几个查询结果行必须是一致的。 Su*f`~G];
12、说明:使用外连接 6!$2nK+
A、left outer join: >NMq^J'/
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Gm.2!F=R4A
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }y&tF'qG
B:right outer join: 4B$|UG
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。 !63]t?QXMG
C:full outer join: owKOH{otf
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。 +LB2V3UZ
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二、提升 " gQJeMU
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) :@]%n~x
法一:select * into b from a where 1<>1 45U!\mG
法二:select top 0 * into b from a ? uu, w
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) V8-*dE
insert into b(a, b, c) select d,e,f from b; Q~zs]{\
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) `FHKQS5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?my2dd,|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. )=5,S~IT
4、说明:子查询(表名1:a 表名2:b) rPUk%S
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) .)[0yW&
5、说明:显示文章、提交人和最后回复时间 .
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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 b<\aJb{2
6、说明:外连接查询(表名1:a 表名2:b) +(/' b'*
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c N"-U)d-.
7、说明:在线视图查询(表名1:a ) K6G+sBw[
select * from (SELECT a,b,c FROM a) T where t.a > 1; Qa@]
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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 m
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select * from table1 where time between time1 and time2 B*&HQW *u
select a,b,c, from table1 where a not between 数值1 and 数值2 ihBIE
9、说明:in 的使用方法 Cd'`rs}3
select * from table1 where a [not] in ('值1','值2','值4','值6') *RJiHcII
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~jDf,a2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5h@5.-}
11、说明:四表联查问题: _qvzZ6
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 ..... Sgq" 3(+%,
12、说明:日程安排提前五分钟提醒 |DkK7gw
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 M&J$9X
13、说明:一条sql 语句搞定数据库分页 'h3yxf}\
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ?~=5x
14、说明:前10条记录 HC(7,3
select top 10 * form table1 where 范围 u5rHQA0%
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) \Y^GA;AMQQ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5\.w\
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 a_U[!`/w
(select a from tableA ) except (select a from tableB) except (select a from tableC) q:<vl^<j
17、说明:随机取出10条数据 ~=k?ea/>
select top 10 * from tablename order by newid() q"$C)o
18、说明:随机选择记录 xM2UwTpW
select newid() +~\ 1g^h
19、说明:删除重复记录 G6q*U,
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f(E[jwy
20、说明:列出数据库里所有的表名 &@fW6},iW
select name from sysobjects where type='U' xFp?+a
21、说明:列出表里的所有的 9^1li2z k{
select name from syscolumns where id=object_id('TableName') @~C
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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。 ,&iZ*6=X?0
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 0P^&{ek+)
显示结果: Qv;q*4_
type vender pcs M%v 6NxN
电脑 A 1 sj8lvIY5
电脑 A 1 dLtmG:II
光盘 B 2 M@<r8M]G
光盘 A 2 a,eJO ??
手机 B 3 NN]8T
手机 C 3 O6$n VpD3
23、说明:初始化表table1 t-?#x
TRUNCATE TABLE table1 w"
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24、说明:选择从10到15的记录 8T}Dn\f
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc h)h%y)1
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三、技巧 6ac_AsFK
1、1=1,1=2的使用,在SQL语句组合时用的较多 {ug*
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3"LT ''
如: +@qIDUiF3
if @strWhere !='' D8\9nHUD`
begin i#:M2&twE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere <|1Kh ygv
end NKMVp/66D
else d-'BT(@:
begin f[Xsri
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' FE3uNfQs|
end EpB3s{B"
我们可以直接写成 DA^!aJ6iF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :Ny^-4-N
2、收缩数据库 O PJ(ub
--重建索引 ?e2G{0V
DBCC REINDEX \JDxN
DBCC INDEXDEFRAG $%.,=~W7
--收缩数据和日志 j026CVL
DBCC SHRINKDB BE)&.}l
DBCC SHRINKFILE MN[D)RKh;
3、压缩数据库 & {=}U
dbcc shrinkdatabase(dbname) _@! yj
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' to(lE2`.da
go hr`,s!0Y
5、检查备份集 KskPFXxP
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3*#$:waGd
6、修复数据库 ~WKWx.ul
ALTER DATABASE [dvbbs] SET SINGLE_USER Q& S 7_
GO ]e(\<R6Gf
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <$Djags,F
GO DqA$%b
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ALTER DATABASE [dvbbs] SET MULTI_USER FYIz_GTk
GO GC7W7B
7、日志清除 yi*EE%
SET NOCOUNT ON hCob^o
DECLARE @LogicalFileName sysname, g"v6UZ\
@MaxMinutes INT, fU|4^p)
@NewSize INT 9 e;8"rJ?C
USE tablename -- 要操作的数据库名 fE1VTGfd:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 :;K Q]<
@MaxMinutes = 10, -- Limit on time allowed to wrap log. wQ?Z y;/S
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2Ws'3Jz
-- Setup / initialize IAMtMO^L
DECLARE @OriginalSize int H
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SELECT @OriginalSize = size ~toR)=Yv
FROM sysfiles iz3Hoj
WHERE name = @LogicalFileName uLr-!T
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8\rAx P}=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + m'WGK`WIm
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' BFZ\\rN`
FROM sysfiles ?I"FmJ;
WHERE name = @LogicalFileName ^+x ,211f
CREATE TABLE DummyTrans ]-jaIvM
(DummyColumn char (8000) not null) {Zo*FZcaX
DECLARE @Counter INT, B/dJj#
@StartTime DATETIME, '#lc?Y(pJ2
@TruncLog VARCHAR(255)
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SELECT @StartTime = GETDATE(), MUUhg
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' EpK7VW
DBCC SHRINKFILE (@LogicalFileName, @NewSize) m O"Rq5
EXEC (@TruncLog) =yZ6 $ hK
-- Wrap the log if necessary. R0e!b+MZ.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired C:z7R" yj
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) IwR=@Ne8
AND (@OriginalSize * 8 /1024) > @NewSize O)c3Lm-w
BEGIN -- Outer loop. o.wXaS8
SELECT @Counter = 0 z`sW5K(A
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I].ddR%
BEGIN -- update 7>f)pfLM
INSERT DummyTrans VALUES ('Fill Log') ~^>g<YR[
DELETE DummyTrans BiA^]h/|
SELECT @Counter = @Counter + 1 K0\`0E^,
END r{wf;5d(
EXEC (@TruncLog) B C R]K
END g ,yB^^%
SELECT 'Final Size of ' + db_name() + ' LOG is ' + GW2v&Ul7(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + K~+x@O*
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' jvhD_L/
FROM sysfiles Tsocc5gWZ*
WHERE name = @LogicalFileName Y4N)yMSl"
DROP TABLE DummyTrans ekd;sEO
SET NOCOUNT OFF #M<u^$Jz
8、说明:更改某个表 !}q@O-}j
exec sp_changeobjectowner 'tablename','dbo' ge#P(Itz
9、存储更改全部表 7-mo\jw<
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch {BZ0x2
@OldOwner as NVARCHAR(128), tR(L>ZG{
@NewOwner as NVARCHAR(128) |WSmpuf
AS c
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DECLARE @Name as NVARCHAR(128) q#`;G,rs
DECLARE @Owner as NVARCHAR(128) S+l>@wa)|
DECLARE @OwnerName as NVARCHAR(128) 6C!TXV'
DECLARE curObject CURSOR FOR jF-0 fK;)*
select 'Name' = name, L#fS P
'Owner' = user_name(uid) 40$9./fe)
from sysobjects o3HS|
where user_name(uid)=@OldOwner JqtOoR
order by name $'KhA6u
OPEN curObject ~R7{gCqdr
FETCH NEXT FROM curObject INTO @Name, @Owner $E^*^({
WHILE(@@FETCH_STATUS=0) CJ [e^K{
BEGIN Ni#y=cb
if @Owner=@OldOwner {'cdi`
begin %:y"o_X_
set @OwnerName = @OldOwner + '.' + rtrim(@Name) d.k'\1o
exec sp_changeobjectowner @OwnerName, @NewOwner &Qt1~#1
end R^rA.7T
-- select @name,@NewOwner,@OldOwner ).jna`A,
FETCH NEXT FROM curObject INTO @Name, @Owner =cxG4R1x
END Vu,:rPqI
close curObject :AyZe7:(D
deallocate curObject ?uXY 6J"
GO ZK8DziO
10、SQL SERVER中直接循环写入数据 :fQN_*B4@4
declare @i int a KIS%M#Y
set @i=1 4|NcWpaV7
while @i<30 0$|wj^?U
begin soqnr"
1
insert into test (userid) values(@i) #!4`t]E<
set @i=@i+1 Mm%b8#Fe!
end =6BI[_0
小记存储过程中经常用到的本周,本月,本年函数 hroRDD
Dateadd(wk,datediff(wk,0,getdate()),-1) F8B:P7I
Dateadd(wk,datediff(wk,0,getdate()),6) 8},fu3Z
Dateadd(mm,datediff(mm,0,getdate()),0) uKo4nXVtp
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) mWuhXY^Q
Dateadd(yy,datediff(yy,0,getdate()),0) <n0j'P>1
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :KsBJ>2ck
上面的SQL代码只是一个时间段 4}Hf"L[ l
Dateadd(wk,datediff(wk,0,getdate()),-1) Co`:D
Dateadd(wk,datediff(wk,0,getdate()),6) ]CgZt'h{
就是表示本周时间段. :U-yO 9!j
下面的SQL的条件部分,就是查询时间段在本周范围内的: uN6xOq/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |2&|#K4k^
而在存储过程中 BA_l*h%=Cc
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }tedh
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) BF
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