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。 c!/+0[
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一、基础 zX4RqI
1、说明:创建数据库 N+@ Ff3M
CREATE DATABASE database-name w.a9}GC
2、说明:删除数据库 ,(pp+hNq
drop database dbname q\]X1N
3、说明:备份sql server }cr'o"4
--- 创建 备份数据的 device YrB-n
USE master f?51sr
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' dGn0-l'q
--- 开始 备份 eqsmv[
BACKUP DATABASE pubs TO testBack j~G(7t
4、说明:创建新表 }#7rg_O]>
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) yV )fJ_
根据已有的表创建新表: 0hV#]`9`gN
A:create table tab_new like tab_old (使用旧表创建新表) {;u,04OVK
B:create table tab_new as select col1,col2... from tab_old definition only Z$JJ0X
5、说明:删除新表 UZ2_FP
drop table tabname YLGE{bS
6、说明:增加一个列 BEvY&3%l
Alter table tabname add column col type bo/9k 4N3
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 X<$Tn60,
7、说明:添加主键: Alter table tabname add primary key(col) @,TIw[p
说明:删除主键: Alter table tabname drop primary key(col) fy4zBI@
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q_|}~4_+
删除索引:drop index idxname 8c+V$rH_
注:索引是不可更改的,想更改必须删除重新建。 "(7y%TFt:
9、说明:创建视图:create view viewname as select statement A*?PH`bY
删除视图:drop view viewname d\l{tmte
10、说明:几个简单的基本的sql语句 Syy{ ^Ae}
选择:select * from table1 where 范围 rZJJ\ , |
插入:insert into table1(field1,field2) values(value1,value2) j2<+[h-
删除:delete from table1 where 范围 ~TEn +
更新:update table1 set field1=value1 where 范围 .R)P
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uC^)#Y\"
排序:select * from table1 order by field1,field2 [desc] Cl<!S`
总数:select count as totalcount from table1 P:4"~]}
求和:select sum(field1) as sumvalue from table1 dAx
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平均:select avg(field1) as avgvalue from table1 8qg%>ZU4d
最大:select max(field1) as maxvalue from table1 C$TU
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最小:select min(field1) as minvalue from table1 ou <3}g
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11、说明:几个高级查询运算词
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A: UNION 运算符 B_Q{B|eEt&
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。 )|xu5.F
B: EXCEPT 运算符 Q_0+N3
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。 aC\f;&P>
C: INTERSECT 运算符 z&amYwQcI
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。 9 A ?{}c
注:使用运算词的几个查询结果行必须是一致的。 Zek@xr;]
12、说明:使用外连接 WJhTU@'
A、left outer join: mG&A_/e!9
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。 W3tin3__
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 N7_eLhPt*8
B:right outer join: ]EX6Y
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。 >] 'oN
C:full outer join: {x_.QWe5
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。 0N$7(.
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二、提升 id1cZig
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |VWT4*K
法一:select * into b from a where 1<>1 w~b:9_reY
法二:select top 0 * into b from a i"0Bc{cQ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ,SR7DiYg
insert into b(a, b, c) select d,e,f from b; QPDh!A3T
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) FpRYffT 9u
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 n?EgC8b9
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. KUUA>'=
4、说明:子查询(表名1:a 表名2:b) =#V^t$
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) xR0T'@q
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 iQgg[
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6、说明:外连接查询(表名1:a 表名2:b) 8@m$(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 eUA]OF@
7、说明:在线视图查询(表名1:a ) UPuoIfuqI
select * from (SELECT a,b,c FROM a) T where t.a > 1; "#r)NYq`"|
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 u;_h%z5K
select * from table1 where time between time1 and time2 7EE{*}?0E
select a,b,c, from table1 where a not between 数值1 and 数值2 fZo#:"{/K
9、说明:in 的使用方法 sE% $]Jp
select * from table1 where a [not] in ('值1','值2','值4','值6') Z
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 o%t4WQ|bj
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5CFNBb%Xy
11、说明:四表联查问题: U|}
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... VV$t*9w
12、说明:日程安排提前五分钟提醒 M,]|L c h
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 k."p&
13、说明:一条sql 语句搞定数据库分页 \~
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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 d&j
14、说明:前10条记录 %lHHTZ{+
select top 10 * form table1 where 范围 \;X7DK2
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.) +lx&$mr?
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2|je{
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`Z/B[)
(select a from tableA ) except (select a from tableB) except (select a from tableC) uAn}qrqE9
17、说明:随机取出10条数据 5daq}hsQs
select top 10 * from tablename order by newid() ]c/E7|0Q
18、说明:随机选择记录 2FIL@f|\7z
select newid() y/Xs+ {x
19、说明:删除重复记录 'k,2*.A
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) la3B`p
20、说明:列出数据库里所有的表名 jzbq{#
select name from sysobjects where type='U' R@o&c%K"
21、说明:列出表里的所有的 'o-4'
select name from syscolumns where id=object_id('TableName') D@bGJc0
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。 D<S C
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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 [s(D==8
显示结果: dht0PZdx?
type vender pcs =u<:'\_
电脑 A 1 dkC[SG`
电脑 A 1 cV+?j}"*+
光盘 B 2 MVYd\)\o
光盘 A 2 *LEy#N
手机 B 3 oACAC+CP
手机 C 3 CxFd/X,
23、说明:初始化表table1 %!<Y
TRUNCATE TABLE table1 .e~"+Pe6b
24、说明:选择从10到15的记录 }UhYwJf89
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc R=z])
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三、技巧 3Qy@^"
1、1=1,1=2的使用,在SQL语句组合时用的较多 CvoFt=c$jE
"where 1=1" 是表示选择全部 "where 1=2"全部不选, npdljLN
如: 928_e)V
if @strWhere !='' U)J5K
begin '$9o(m#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere YWFE*wQ!
end oW3"J6,S
else m@Z#
begin $h#sb4ek
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' OEW'bT)
end ETp?R WXX
我们可以直接写成 %O"8|ZG9{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere mO>L]<O
2、收缩数据库 Pyo|Sgk
--重建索引 K zWo}tT
DBCC REINDEX 'R7 \
DBCC INDEXDEFRAG V@
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--收缩数据和日志 n#(pT3&
DBCC SHRINKDB V(7,N(
DBCC SHRINKFILE JVc{vSa!rm
3、压缩数据库 :"%/u9<A
dbcc shrinkdatabase(dbname) G|wtl(}3
4、转移数据库给新用户以已存在用户权限 2cMCZuO
exec sp_change_users_login 'update_one','newname','oldname' r_T)|||v
go aFnel8
5、检查备份集 pXk^EV0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' UqP{Cyy{
6、修复数据库 ]\(8d[4
ALTER DATABASE [dvbbs] SET SINGLE_USER X6Ha C+P
GO 02-ql
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK MEDh
GO /F0q8j0
ALTER DATABASE [dvbbs] SET MULTI_USER M+/G>U
GO Vj*-E
7、日志清除 5hrI#fpOR
SET NOCOUNT ON H"A%mrb
DECLARE @LogicalFileName sysname, >e;-$$e
@MaxMinutes INT, qRt! kWW
@NewSize INT V1aP_G-:
USE tablename -- 要操作的数据库名 hOj{y2sc
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @62T:Vl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. '}.Yf_
@NewSize = 1 -- 你想设定的日志文件的大小(M) 5ya9VZ5#
-- Setup / initialize fkV@3sj
DECLARE @OriginalSize int gaF6j!p
SELECT @OriginalSize = size \@<7Vo,
FROM sysfiles 4EB\R"rWXf
WHERE name = @LogicalFileName jI-a+LnEm
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?.~1%l !
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + &\h7E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \-\>JPO~<
FROM sysfiles Ew8@{X
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WHERE name = @LogicalFileName .~]|gg~
CREATE TABLE DummyTrans ]eL# bJ
(DummyColumn char (8000) not null) fUT[tkb/!
DECLARE @Counter INT, ?UXFz'
@StartTime DATETIME, dOhSqx56
@TruncLog VARCHAR(255) +,Eam6g{
SELECT @StartTime = GETDATE(), ZEqW*piI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 'a~@q~!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ~ ld.I4
EXEC (@TruncLog) 2dn^K3
-- Wrap the log if necessary. 7({)ou x
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <kn2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -C=0Pg]ga
AND (@OriginalSize * 8 /1024) > @NewSize 78&|^sq
BEGIN -- Outer loop. "5hk%T'
SELECT @Counter = 0 U&^q#['
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) hkMeUxS
BEGIN -- update 0m@+ &X>w
INSERT DummyTrans VALUES ('Fill Log') -Jd|H*wWo
DELETE DummyTrans QS#@xhH
SELECT @Counter = @Counter + 1 n:@!vV
END vW+6_41ZM
EXEC (@TruncLog) \""^'pP@
END Bx?3E^!T
SELECT 'Final Size of ' + db_name() + ' LOG is ' + UK =ELvt]
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,.,8-In^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' iJs~NLCgVu
FROM sysfiles o@meogkL
WHERE name = @LogicalFileName }d[(kC_
DROP TABLE DummyTrans ^FVdA1~/
SET NOCOUNT OFF +f3Rzx]
8、说明:更改某个表 opcanl9pSW
exec sp_changeobjectowner 'tablename','dbo' v:O{"s
9、存储更改全部表 '/\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch mqSVd^
@OldOwner as NVARCHAR(128), }lZEdF9GhG
@NewOwner as NVARCHAR(128) GBJLB
AS |XyX%5p*
DECLARE @Name as NVARCHAR(128) QPlU+5Cx
DECLARE @Owner as NVARCHAR(128) X 4;U4pU#
DECLARE @OwnerName as NVARCHAR(128) `4"8@>D
DECLARE curObject CURSOR FOR W}(A8g#6
select 'Name' = name, jPh<VVQ$@
'Owner' = user_name(uid) i
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from sysobjects SB62(#YR
where user_name(uid)=@OldOwner _"8n&=+
order by name 'E|%l!xO
OPEN curObject i VSNara
FETCH NEXT FROM curObject INTO @Name, @Owner :5YIoC
WHILE(@@FETCH_STATUS=0) ]N>ZOV,>
BEGIN #:)'D?,
if @Owner=@OldOwner sI>w#1.m/&
begin 0seCQANd
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g6M>S1oOO
exec sp_changeobjectowner @OwnerName, @NewOwner [|nK5(e9
end E7uIur=g!
-- select @name,@NewOwner,@OldOwner ]c(FgYc
FETCH NEXT FROM curObject INTO @Name, @Owner +R'8$
END +=tdgw/
close curObject )GB#"2
deallocate curObject .:S/x{~
GO ]ch=@IV
10、SQL SERVER中直接循环写入数据 C,| &
declare @i int XC<fNK
set @i=1 >"W^|2R
while @i<30 /}:{(Go
begin !(d]f0
insert into test (userid) values(@i) %YG?7PBB
set @i=@i+1 V)$!WPL@
end C5 ~#lNC
小记存储过程中经常用到的本周,本月,本年函数 a&s34Pd
Dateadd(wk,datediff(wk,0,getdate()),-1) kWzp*<lWe
Dateadd(wk,datediff(wk,0,getdate()),6) ~
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Dateadd(mm,datediff(mm,0,getdate()),0) dSDZMB sd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) u8f\)m
Dateadd(yy,datediff(yy,0,getdate()),0) y0%@^^-Ru
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9q;O`&
上面的SQL代码只是一个时间段 !BQt+4G7
Dateadd(wk,datediff(wk,0,getdate()),-1) $QJ3~mG2
Dateadd(wk,datediff(wk,0,getdate()),6) *i"9D:
就是表示本周时间段. xm m,-u
下面的SQL的条件部分,就是查询时间段在本周范围内的: o/AG9|()4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~j!n`#.\
而在存储过程中 i"Jy>'
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (4H\ho8+mp
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) SioeIXU