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。 gNeCnf#Xa
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一、基础 ?0x;L/d])
1、说明:创建数据库 YAog;QL
CREATE DATABASE database-name va0
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2、说明:删除数据库
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drop database dbname Z6p>R;9n
3、说明:备份sql server nL?B
--- 创建 备份数据的 device !ktr|9Bl
USE master {~SR>I3sv
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 5eYCnc9
--- 开始 备份 /[OMpP
BACKUP DATABASE pubs TO testBack /%)J+K)
4、说明:创建新表 ]:;gk&P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) x^"OH
根据已有的表创建新表: 3-05y!vbcE
A:create table tab_new like tab_old (使用旧表创建新表) [ ,dsVd
B:create table tab_new as select col1,col2... from tab_old definition only ~BC5no
5、说明:删除新表 V;!D:N8<
drop table tabname 4ZIXG,@mZJ
6、说明:增加一个列 ll#PCgIm
Alter table tabname add column col type ]O[f#lG
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。 {9)f~EbM!
7、说明:添加主键: Alter table tabname add primary key(col) XxIU B(.QI
说明:删除主键: Alter table tabname drop primary key(col) yVL~SH|
8、说明:创建索引:create [unique] index idxname on tabname(col....) EQ28pAZ
删除索引:drop index idxname cH#`f4
注:索引是不可更改的,想更改必须删除重新建。 C8?/$1|RL
9、说明:创建视图:create view viewname as select statement 7G/"!ePW6`
删除视图:drop view viewname ^^Ius ]
10、说明:几个简单的基本的sql语句 @*oi1_q
选择:select * from table1 where 范围 z|9 ^T@)
插入:insert into table1(field1,field2) values(value1,value2) T<OLfuV
删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 V{n pK(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ?$
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排序:select * from table1 order by field1,field2 [desc] b7$?'neH/.
总数:select count as totalcount from table1 CB~&!MdMr
求和:select sum(field1) as sumvalue from table1 Bpgl
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平均:select avg(field1) as avgvalue from table1 ,YoIn
最大:select max(field1) as maxvalue from table1 NYCkYI
最小:select min(field1) as minvalue from table1 . "R
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11、说明:几个高级查询运算词 = *sP,
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A: UNION 运算符 HJ2]xe09
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Z#F2<*+Pe
B: EXCEPT 运算符 zn M"P|A
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 QKVZ![Y!s
C: INTERSECT 运算符 9TF[uC)-2
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 P"- ,^?6
注:使用运算词的几个查询结果行必须是一致的。 p~r +2(J
12、说明:使用外连接 w,\Ua&>4
A、left outer join: cD{[rI
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 `Z{7Ut^)
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c fD!O
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B:right outer join: E_xpq
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 SO}Hc;Q1`
C:full outer join: t+vn.X+&
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 7c+u+Yet
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二、提升 K$rH{dUM
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) nGRF<2!
法一:select * into b from a where 1<>1 Q
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法二:select top 0 * into b from a zRB1V99k
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bJ9>,,D
insert into b(a, b, c) select d,e,f from b; GwpJxiFgk
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)
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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 FO*Py)/rX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Nf3L
4、说明:子查询(表名1:a 表名2:b) 0BD3~Lv
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 $?VYC8;
5、说明:显示文章、提交人和最后回复时间 d(h`bOjI
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b JL]6o8x
6、说明:外连接查询(表名1:a 表名2:b) *s_)E2
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Xh){W~-
7、说明:在线视图查询(表名1:a ) @$Y`I{Xf
select * from (SELECT a,b,c FROM a) T where t.a > 1; $ZE OE8.\
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -FJ5N}R
select * from table1 where time between time1 and time2 S9mj/GpL3
select a,b,c, from table1 where a not between 数值1 and 数值2 )u<sEF
9、说明:in 的使用方法 7XdLZ4ub
select * from table1 where a [not] in ('值1','值2','值4','值6') P_w+p"@m
10、说明:两张关联表,删除主表中已经在副表中没有的信息 kRG-~'f%`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) c,e
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11、说明:四表联查问题: Pg5 1}{
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... T#T!a0
12、说明:日程安排提前五分钟提醒 9!PJLI=D
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zX(p\NU
13、说明:一条sql 语句搞定数据库分页 aWW|.#L
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 _t3n<
14、说明:前10条记录 1 [dza5
select top 10 * form table1 where 范围 {V8v
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 5y@JMQSO
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) EpS"NQEe
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 eFbr1IV
(select a from tableA ) except (select a from tableB) except (select a from tableC) O7:JG[tR*
17、说明:随机取出10条数据 ~^Gk7
select top 10 * from tablename order by newid() @TsOc0?-
18、说明:随机选择记录 }F**!%4d
select newid() _aq3G9C_
19、说明:删除重复记录 _v<EFal
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +K]kGF
20、说明:列出数据库里所有的表名 {R]4N]l>
select name from sysobjects where type='U' f5^[`b3H
21、说明:列出表里的所有的 H$WuT;cTE
select name from syscolumns where id=object_id('TableName') 7 zK%CJ
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。 ~-JkuRJ\
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 lY0^Z
显示结果: &R>x;&Gj
type vender pcs T[L
电脑 A 1 HBeOK
电脑 A 1 f0}+8JW5h
光盘 B 2 zR">'bM:
光盘 A 2 9 *Q/3|
手机 B 3 b4i=eI8
手机 C 3 PWx2<t<;9
23、说明:初始化表table1 *r$(lf
TRUNCATE TABLE table1 StA5h+[m
24、说明:选择从10到15的记录 $
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 3\G&fb|?}R
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三、技巧 cYq<.A(hVj
1、1=1,1=2的使用,在SQL语句组合时用的较多 u-yQP@^H
"where 1=1" 是表示选择全部 "where 1=2"全部不选, do C8!
如: >kd&>)9v
if @strWhere !='' R"VmN2
begin H5{d;L1[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere SX$v&L<
end c{7!:hi`x
else %5NfF65'
begin TnCN2#BO
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l+Uy
end :6./yj(
我们可以直接写成 d7qHUx'=z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere N)WAzH
2、收缩数据库 xm6cn\e
--重建索引 8$BZbj%?hx
DBCC REINDEX ZV$qv=X
DBCC INDEXDEFRAG /9QI^6&SX
--收缩数据和日志 $ohIdpZLH2
DBCC SHRINKDB 7lqj" o(
DBCC SHRINKFILE ;*[nZV>
3、压缩数据库 1Y_Cd
dbcc shrinkdatabase(dbname) A90oX1l
4、转移数据库给新用户以已存在用户权限 "(>P=
exec sp_change_users_login 'update_one','newname','oldname' ,GA2K .:#
go 8.ll]3))
5、检查备份集 V \,Z (
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' jqhd<w
6、修复数据库 m\)z& hv<r
ALTER DATABASE [dvbbs] SET SINGLE_USER D4?5% s
GO rp (nGiI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK d;daYjOm
GO qe8dpI;
ALTER DATABASE [dvbbs] SET MULTI_USER h S/oOeG<Y
GO ]'3e#Cqeh
7、日志清除 |X,T>{V?y
SET NOCOUNT ON y'(l]F1]
DECLARE @LogicalFileName sysname, xv4_q-r[
@MaxMinutes INT, PMe bn$(
@NewSize INT |[7xTD
USE tablename -- 要操作的数据库名 {L$ ]NQdz
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >jD,%yG
@MaxMinutes = 10, -- Limit on time allowed to wrap log. W2e~!:w
@NewSize = 1 -- 你想设定的日志文件的大小(M) C0|<+3uND=
-- Setup / initialize Pwn"!pk
DECLARE @OriginalSize int ],YIEOx6
SELECT @OriginalSize = size QqA~y$'ut
FROM sysfiles BWamF{\d1a
WHERE name = @LogicalFileName z|;7;TwA
SELECT 'Original Size of ' + db_name() + ' LOG is ' + E5(\/;[*`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \$n?J(N
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' eLXG _Qb"
FROM sysfiles q-P$ \":
WHERE name = @LogicalFileName uDJi2,|n
CREATE TABLE DummyTrans ~3<Li}W
(DummyColumn char (8000) not null) {p&LwTnf
DECLARE @Counter INT, ^AS*X2y
@StartTime DATETIME, UT|FV
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@TruncLog VARCHAR(255) #05#@v8.f
SELECT @StartTime = GETDATE(), 0*o)k6?q3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2iYf)MC
DBCC SHRINKFILE (@LogicalFileName, @NewSize) gswp:82e2
EXEC (@TruncLog) ~( 54-9&
-- Wrap the log if necessary. ;3wj(o0
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired @AYO )Y8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?&W1lYY
AND (@OriginalSize * 8 /1024) > @NewSize d~1Nct$:
BEGIN -- Outer loop. MQ>.^]B]o
SELECT @Counter = 0 6m"_=.k%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) %T4htZa
BEGIN -- update b1Bu5%bt,:
INSERT DummyTrans VALUES ('Fill Log') KLK
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DELETE DummyTrans m_{OCHS+
SELECT @Counter = @Counter + 1 P{v>o,a.
END ;`Eie2y{M
EXEC (@TruncLog) c|OIUc
END -h+=^,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + O)NEt
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + VDq4n;p1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ij i<+oul
FROM sysfiles 69AgPAv<k
WHERE name = @LogicalFileName GInU7y904
DROP TABLE DummyTrans %upnXRzw
SET NOCOUNT OFF [zmx
8、说明:更改某个表 W!|A3V35\:
exec sp_changeobjectowner 'tablename','dbo' pcwkO
9、存储更改全部表 mVFz[xI
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $xqI3UaX
@OldOwner as NVARCHAR(128), <Hw)},_*
@NewOwner as NVARCHAR(128) %"Tn=fZIF
AS 'wB6-
DECLARE @Name as NVARCHAR(128) 7A'd55I4
DECLARE @Owner as NVARCHAR(128) rV.04m,
DECLARE @OwnerName as NVARCHAR(128) JbN@AX:%
DECLARE curObject CURSOR FOR ~"F83+RDe
select 'Name' = name, CMn&1
'Owner' = user_name(uid) |d}f\a`
from sysobjects dXR70/
where user_name(uid)=@OldOwner .zxP,]"l
order by name gn"Y?IZ?
OPEN curObject aN9#ATE
FETCH NEXT FROM curObject INTO @Name, @Owner /c/t_xB
WHILE(@@FETCH_STATUS=0) Y
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BEGIN E=!=4"rZF
if @Owner=@OldOwner @*SgeLeL
begin +mP&B<=H)
set @OwnerName = @OldOwner + '.' + rtrim(@Name) mv9k_7<
exec sp_changeobjectowner @OwnerName, @NewOwner YYfX@`\
end S0?4}7`A
-- select @name,@NewOwner,@OldOwner J-C3k`%O
FETCH NEXT FROM curObject INTO @Name, @Owner $t.i)wg +
END ~xI1@^r
close curObject wBlfQ
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deallocate curObject :.KN;+tP
GO b=[gK|fu
10、SQL SERVER中直接循环写入数据 7%rSo^t,L
declare @i int Fy4jujP<
set @i=1 3/sKRU
while @i<30 g8+w?Zn}
begin oicett=5
insert into test (userid) values(@i) HVb9YU+
set @i=@i+1 e|wH5(V
end HnvE\t9`
小记存储过程中经常用到的本周,本月,本年函数 BoZG^
Dateadd(wk,datediff(wk,0,getdate()),-1) ] iKFEd
Dateadd(wk,datediff(wk,0,getdate()),6) BKoc;20;
Dateadd(mm,datediff(mm,0,getdate()),0) 1FfdW>ay*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $V"NB`T
Dateadd(yy,datediff(yy,0,getdate()),0) Qxds]5WB/
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) W#cr9"'Ta
上面的SQL代码只是一个时间段 `Pj7O/!)#!
Dateadd(wk,datediff(wk,0,getdate()),-1) 6T%5vg_};'
Dateadd(wk,datediff(wk,0,getdate()),6) Y.$InQ gL
就是表示本周时间段. J"w!Q\_
下面的SQL的条件部分,就是查询时间段在本周范围内的: ]h (TZu
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) u7|{~D&f
而在存储过程中 e2#"o{+@
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) wv,,#P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (]'Q!MjGa