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。 s)_Xj`Q#
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一、基础 _`6fGu& W
1、说明:创建数据库 C.SGm
CREATE DATABASE database-name __x2xtrH
2、说明:删除数据库 q,b6).
drop database dbname dWR0tS6vR`
3、说明:备份sql server ,E&PIbDL1
--- 创建 备份数据的 device P'Q|0lB
USE master S $wx>715
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' N>,`l
--- 开始 备份 lMpjE
BACKUP DATABASE pubs TO testBack y+3<
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4、说明:创建新表 ~ Iin|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }e}J6[wP
根据已有的表创建新表: H(qDQqJHYy
A:create table tab_new like tab_old (使用旧表创建新表) W<Ms0
B:create table tab_new as select col1,col2... from tab_old definition only 7:fC,2+
5、说明:删除新表 0bY}<x(;
drop table tabname sTu6KMn
6、说明:增加一个列 tvNh@it:F
Alter table tabname add column col type 0Q@
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 om$x;L6
7、说明:添加主键: Alter table tabname add primary key(col) !>$tRW?gH~
说明:删除主键: Alter table tabname drop primary key(col) CD$0Z
8、说明:创建索引:create [unique] index idxname on tabname(col....) XXuIWIhm
删除索引:drop index idxname sT|$@$bN
注:索引是不可更改的,想更改必须删除重新建。 {XC1B
9、说明:创建视图:create view viewname as select statement 3GEI) !
删除视图:drop view viewname {d`e9^Z:
10、说明:几个简单的基本的sql语句 S+c)
选择:select * from table1 where 范围 ~udi=J|
插入:insert into table1(field1,field2) values(value1,value2) b"U{@
删除:delete from table1 where 范围 25xpq^Zw
更新:update table1 set field1=value1 where 范围 eKdF-;
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D ff0$06Nq
排序:select * from table1 order by field1,field2 [desc] ,sEu[m
总数:select count as totalcount from table1 XA8{N
求和:select sum(field1) as sumvalue from table1 X+l&MD
平均:select avg(field1) as avgvalue from table1 sGx"ja+
最大:select max(field1) as maxvalue from table1 xyGk\= S
最小:select min(field1) as minvalue from table1 H{*~d+:ol
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11、说明:几个高级查询运算词 d-%!.,F#W
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A: UNION 运算符 $[zy|Y(
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 bzFwQi}>
B: EXCEPT 运算符 O*MC"%T
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 }UwDHq=
C: INTERSECT 运算符 =5bef8 O
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 9Xw(|22
注:使用运算词的几个查询结果行必须是一致的。 "F/% {0d
12、说明:使用外连接 7~@q#]U[
A、left outer join: w}="}Cb
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Ii"h:GY;\
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )l}Gwd]h
B:right outer join: 8^26g3
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 PPiN`GM
C:full outer join: }EB/1 8
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 BD6oN]
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二、提升 AS[yNCsjC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^O_E
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法一:select * into b from a where 1<>1 XV"8R"u%Q
法二:select top 0 * into b from a gkDyWZG B
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \XaKq8uE
insert into b(a, b, c) select d,e,f from b; qKX3Npw
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) m[~fT(NI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 @1_M's;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~Rx:X4|H
4、说明:子查询(表名1:a 表名2:b) 1m$:Rn^
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) I5[HD_g:
5、说明:显示文章、提交人和最后回复时间 >BU"C+a8g
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ,DUD 4 [3
6、说明:外连接查询(表名1:a 表名2:b) I^h^QeBis
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $@t]0
7、说明:在线视图查询(表名1:a ) 37Z@a!#
select * from (SELECT a,b,c FROM a) T where t.a > 1; zS]8ma
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 "8{#R*p
select * from table1 where time between time1 and time2 z;? 32K
select a,b,c, from table1 where a not between 数值1 and 数值2 #*QnO\.
9、说明:in 的使用方法 rPf<8oH
select * from table1 where a [not] in ('值1','值2','值4','值6') 9ohaU
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]"Y?
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) G:'hT=8
11、说明:四表联查问题: xVOoYr>O
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 ..... fUy:TCS
12、说明:日程安排提前五分钟提醒 @VlDi1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 r+6=b"
13、说明:一条sql 语句搞定数据库分页 B%Pg:|
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 V^9c:!aI
14、说明:前10条记录 p*F.WxB)4
select top 10 * form table1 where 范围
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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.) @LQe[`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) !zc?o?~z
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 ~I'1\1
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 #~(J
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select top 10 * from tablename order by newid() koQ\]t'*As
18、说明:随机选择记录 6M({T2e
select newid() x<_uwL2a
19、说明:删除重复记录 0q6$KP}q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) a o"\L0;{
20、说明:列出数据库里所有的表名 UVND1XV^f
select name from sysobjects where type='U' Yyl(<,Yi
21、说明:列出表里的所有的 x+niY;Z E
select name from syscolumns where id=object_id('TableName') y7a84)j3
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ?];?3X~|
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type /G}TPXA
显示结果: 3iKBVN
type vender pcs v(5zSo
电脑 A 1 ^! ?wh
电脑 A 1 ma__LWKM,
光盘 B 2 QtM9G@%
光盘 A 2 ;- ~}g 7$
手机 B 3 Fp3NWvu
手机 C 3 (-'Jf#&X^
23、说明:初始化表table1 C!a#M{:
TRUNCATE TABLE table1 -+9,RtHR7
24、说明:选择从10到15的记录 tWD5Yh>.?$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 9fLxp$`(T
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三、技巧 oT=XCa5
1、1=1,1=2的使用,在SQL语句组合时用的较多 x6-bAf
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~!bA<q
如: '3h"Ol{b
if @strWhere !='' /XfE6SBz
begin rd#O ]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere o5k7$0:t/
end hq.XO=0" k
else {3s=U"\
begin (RhGBgp
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =a!w)z_rw
end VV'K$v3'N8
我们可以直接写成 x=Ef0v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?g7O([*[
2、收缩数据库 E@uxEF
--重建索引 iLd_{
DBCC REINDEX 2<"kfan
DBCC INDEXDEFRAG J0%e6{C1
--收缩数据和日志 #* KmPc+
DBCC SHRINKDB Ze?(N~
DBCC SHRINKFILE 9^D5Sl$g
3、压缩数据库 Wzm!:U2R*
dbcc shrinkdatabase(dbname) o \r6iO
4、转移数据库给新用户以已存在用户权限 ^)\z
exec sp_change_users_login 'update_one','newname','oldname' S.iCkX
go *Fb|iR
5、检查备份集 @nPXu2c?u7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' eaNMcC1
6、修复数据库 R]Iv?)Y
ALTER DATABASE [dvbbs] SET SINGLE_USER $0(~ID
GO V~tZNRJ-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NG)Xk[q4
GO y9/x:n&]
ALTER DATABASE [dvbbs] SET MULTI_USER nqnVFkGd9
GO 7[ 82~jM[
7、日志清除 Q^p>hda
SET NOCOUNT ON },tN{()
DECLARE @LogicalFileName sysname, HutwgPvy
@MaxMinutes INT, }VetaO2*
@NewSize INT zG"*B_l}+
USE tablename -- 要操作的数据库名 Qj:`[#3?2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 p bRU"
@MaxMinutes = 10, -- Limit on time allowed to wrap log. .|Ee,Un
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y2Z<A(W
-- Setup / initialize Z+3j>_Ss
DECLARE @OriginalSize int vv 7T/C
SELECT @OriginalSize = size KFCrJ)
FROM sysfiles /@gD
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WHERE name = @LogicalFileName Z)<ljW
SELECT 'Original Size of ' + db_name() + ' LOG is ' + A1Ia9@=Mf
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R(@B4M2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' oFB~)}f<v
FROM sysfiles V%g$LrLVe
WHERE name = @LogicalFileName 6Db1mvSe
CREATE TABLE DummyTrans 1Y6<i8
(DummyColumn char (8000) not null) }
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DECLARE @Counter INT, 6T! *YrS
@StartTime DATETIME, 2Vas`/~u~
@TruncLog VARCHAR(255) y/k6gl[`
SELECT @StartTime = GETDATE(), IeLG/ fB
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' R$X1Q/#md
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Q#Q]xJH
EXEC (@TruncLog) N`1:U
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-- Wrap the log if necessary. >p [|U`>{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %W~Kx_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) L}UJ`U
AND (@OriginalSize * 8 /1024) > @NewSize vQ>x5\r5O_
BEGIN -- Outer loop. 0+jR,5|
SELECT @Counter = 0 :CH "cbo
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,+-l1GpL
BEGIN -- update 8u
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INSERT DummyTrans VALUES ('Fill Log') X1?7}VO
DELETE DummyTrans =kH7
SELECT @Counter = @Counter + 1 3 GmU$w
END [g`9C!P-G
EXEC (@TruncLog) X<dQq`kZ
END `CA-s
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ^\Tde*48
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + P+ONQN|
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' `[3Iz$K=
FROM sysfiles _U( b
WHERE name = @LogicalFileName -CtLL_ I
DROP TABLE DummyTrans ,l^; ZE
SET NOCOUNT OFF }R4%%)j(Vj
8、说明:更改某个表 |=L~>G
exec sp_changeobjectowner 'tablename','dbo' ^2%_AP0=
9、存储更改全部表 Cx2s5vJX4p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Kmc*z (Q
@OldOwner as NVARCHAR(128), uCO-f<b
@NewOwner as NVARCHAR(128) 1wP#?p)c
AS h}r*
DECLARE @Name as NVARCHAR(128) s\y+ xa:
DECLARE @Owner as NVARCHAR(128) Z
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DECLARE @OwnerName as NVARCHAR(128) GjN/8>/
DECLARE curObject CURSOR FOR @[h)M3DFd
select 'Name' = name, ^
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'Owner' = user_name(uid) s kC*
from sysobjects 4scY8(1
where user_name(uid)=@OldOwner MkgeECMf
order by name (oTtnQ""+
OPEN curObject /\34o{
FETCH NEXT FROM curObject INTO @Name, @Owner EvSo|}JA[
WHILE(@@FETCH_STATUS=0) t0h@i`
BEGIN nI7G"f[%r;
if @Owner=@OldOwner Sm-gi|A
begin #=C!Xx&
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^kJ(bBY
exec sp_changeobjectowner @OwnerName, @NewOwner ^0vK >
end hEla8L4Y
-- select @name,@NewOwner,@OldOwner q}P< Ejq}
FETCH NEXT FROM curObject INTO @Name, @Owner 'X_8j` ]#
END qPqpRi
close curObject n6D9f~8"
deallocate curObject {U@&hE
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GO cdiDfiE
10、SQL SERVER中直接循环写入数据 l)tK/1 W
declare @i int ,{==f7|w
set @i=1 v zgR3r
while @i<30 Ks'msSMC
begin reseu*5
insert into test (userid) values(@i) dz@L}b*
set @i=@i+1 ZGO%lkZ.
end 0?OTa<c
小记存储过程中经常用到的本周,本月,本年函数 $I*ye+a*{q
Dateadd(wk,datediff(wk,0,getdate()),-1) .<&o, D
Dateadd(wk,datediff(wk,0,getdate()),6) {=mf/3.r
Dateadd(mm,datediff(mm,0,getdate()),0) K"4m)B~@Y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) QJiU"1
Dateadd(yy,datediff(yy,0,getdate()),0) eGcc' LBr;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) DP{kin"4I
上面的SQL代码只是一个时间段 K8`Jl=}z%&
Dateadd(wk,datediff(wk,0,getdate()),-1) JLgk?
Dateadd(wk,datediff(wk,0,getdate()),6) !SRElb A;i
就是表示本周时间段. mU0j K@^&M
下面的SQL的条件部分,就是查询时间段在本周范围内的: qQK0s*^W
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) r9nH6 Md\
而在存储过程中 ,dn6z#pb+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) tgmG#b*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) RW| LL@r