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。 t5 G9!Nn
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一、基础 .V,@k7U,V
1、说明:创建数据库 9T<x&
CREATE DATABASE database-name EFz&N\2
2、说明:删除数据库 eA<0$Gs,h
drop database dbname J{Q|mD=
3、说明:备份sql server ~@}Bi@*
--- 创建 备份数据的 device eio4k-
USE master %7|9sQ:
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rW$[DdFA5{
--- 开始 备份 s0vDHkf8
BACKUP DATABASE pubs TO testBack \-g)T}g,I
4、说明:创建新表 .mR8q+I6
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) <7~'; K
根据已有的表创建新表: A}l3cP;
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A:create table tab_new like tab_old (使用旧表创建新表) WPQ fhr#|
B:create table tab_new as select col1,col2... from tab_old definition only q.;u?,|E/
5、说明:删除新表 s7F.sg
drop table tabname 4t=G
6、说明:增加一个列
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Alter table tabname add column col type wRVUu)
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 A<n
7、说明:添加主键: Alter table tabname add primary key(col) RCpR3iC2
说明:删除主键: Alter table tabname drop primary key(col) 4%4 }5UYN
8、说明:创建索引:create [unique] index idxname on tabname(col....) W)bLSL]`E
删除索引:drop index idxname `EaLGzw
注:索引是不可更改的,想更改必须删除重新建。 7j-4TY~
9、说明:创建视图:create view viewname as select statement s%W C/ZK
删除视图:drop view viewname ')cMiX\v
10、说明:几个简单的基本的sql语句 ;=MU';o
选择:select * from table1 where 范围 K|epPGRr
插入:insert into table1(field1,field2) values(value1,value2) {z{bY\
删除:delete from table1 where 范围 tS6qWtE
更新:update table1 set field1=value1 where 范围 vw9@v` k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! M!o##* *`
排序:select * from table1 order by field1,field2 [desc] a^I\ /&aw'
总数:select count as totalcount from table1 Vh4X%b$TV
求和:select sum(field1) as sumvalue from table1 rbWP78
平均:select avg(field1) as avgvalue from table1 -Ps!LI{@
最大:select max(field1) as maxvalue from table1 *_d7E
最小:select min(field1) as minvalue from table1 X9V *UXTc
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11、说明:几个高级查询运算词 ) AvN\sC
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A: UNION 运算符 %WjXg:R
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。 1n;0?MIZ
B: EXCEPT 运算符 =c\>(2D
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。 (,0(
C: INTERSECT 运算符 GBPo8L"9
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。 FOE4>zE
注:使用运算词的几个查询结果行必须是一致的。 ;@oN s-
12、说明:使用外连接 YIG~MP
A、left outer join: xqu}cz
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。 K &N
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 (5-FV p
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B:right outer join: 3EPv"f^V
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。 ]>5/PD,wWy
C:full outer join: sYI-5D]
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。 b gK}-EU
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二、提升 W')Yg5T
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) V Y7[)
法一:select * into b from a where 1<>1 _l89
法二:select top 0 * into b from a \!.B+7t=I
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *Q
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insert into b(a, b, c) select d,e,f from b; [1Qo#w1
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) -lY6|79bF
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 <Zmg#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1~NT.tY
4、说明:子查询(表名1:a 表名2:b) qm/22:&v5
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) hcsP2
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5、说明:显示文章、提交人和最后回复时间 *`5.|{<j{
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b A P?R"%
6、说明:外连接查询(表名1:a 表名2:b) D2Kp|F;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c tEvut=k'
7、说明:在线视图查询(表名1:a ) u04kF^
select * from (SELECT a,b,c FROM a) T where t.a > 1; vN;N/mL
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 2K/4Rf0;
select * from table1 where time between time1 and time2 nAsh:6${
select a,b,c, from table1 where a not between 数值1 and 数值2 4V)kx[j
9、说明:in 的使用方法 TNe l/
select * from table1 where a [not] in ('值1','值2','值4','值6') .SU8)T
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ,is3&9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) rZ}:Z'`
11、说明:四表联查问题: TrEu'yxy8*
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 ..... kTOzSiq
12、说明:日程安排提前五分钟提醒 ( R=:X+ k
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 y51e%n$
13、说明:一条sql 语句搞定数据库分页 :!WHFB
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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 DEKP5?]
14、说明:前10条记录 Z>k#n'm^z
select top 10 * form table1 where 范围 "o-zy'I
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.) $r@zs'N
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6]WAUK%h
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 |\pj;XU
(select a from tableA ) except (select a from tableB) except (select a from tableC) h+g_rvIG*
17、说明:随机取出10条数据 /NI;P]s.
select top 10 * from tablename order by newid() y.mda:$~=
18、说明:随机选择记录 |4;Fd9q^m
select newid() "^})zf~_
19、说明:删除重复记录 IL#"~D?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) hF~n)oQ
20、说明:列出数据库里所有的表名 `ts$(u.w
select name from sysobjects where type='U' k8&;lgO'
21、说明:列出表里的所有的 HdUQCugxx:
select name from syscolumns where id=object_id('TableName') Fo5FNNiID
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 {HltvO%8
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type XpB_N{v9w
显示结果: pP&7rRhw
type vender pcs Qb-M6ihcc
电脑 A 1 LM<qT-/qs
电脑 A 1 l*(8i ^
光盘 B 2 %rL.|q9
光盘 A 2 NX*Q F+
手机 B 3 O`IQ(,yef
手机 C 3 'T*&'RQr
23、说明:初始化表table1 99e.n0
TRUNCATE TABLE table1 P9^Xm6QO
24、说明:选择从10到15的记录 AUG#_HE]k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc c<:-T
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三、技巧 |.: q
1、1=1,1=2的使用,在SQL语句组合时用的较多 [6Izlh+D
"where 1=1" 是表示选择全部 "where 1=2"全部不选, q_[o"wq/
如: ]nn98y+
if @strWhere !='' %D{6[8
begin i
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere iy.p n
end @alK;\
else {L{o]Ii?g
begin _}Ac n$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' HmGWht6R
end oq
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我们可以直接写成 Ju@c~Xm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere EH J.T~X
2、收缩数据库 t\dN DS
--重建索引 *aM=Z+
DBCC REINDEX U)o-8OEZ9
DBCC INDEXDEFRAG jp%S3)
--收缩数据和日志 z#wkiCRYm
DBCC SHRINKDB T4Uev*A
DBCC SHRINKFILE <44G]eb
3、压缩数据库 Cv.C;H
dbcc shrinkdatabase(dbname) lfow1WRF
4、转移数据库给新用户以已存在用户权限 E4jNA}3k+
exec sp_change_users_login 'update_one','newname','oldname' vH@ds
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go 2*& ^v
5、检查备份集 pI\]6U
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?(1y
6、修复数据库 R B
ALTER DATABASE [dvbbs] SET SINGLE_USER |mfvr*7
GO 6@5+m
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK +Mb.:_7'
GO dFB]~QEK
ALTER DATABASE [dvbbs] SET MULTI_USER GR_-9}jQP
GO `4J$Et%S
7、日志清除 lukB8
SET NOCOUNT ON iOghb*aW
DECLARE @LogicalFileName sysname, p?OoC
@MaxMinutes INT, tX s\R(?T
@NewSize INT k1~&x$G
USE tablename -- 要操作的数据库名 cOJo3p;&
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 jvL[
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ynj,pl
@NewSize = 1 -- 你想设定的日志文件的大小(M) =&]g "a'
-- Setup / initialize S9y}
DECLARE @OriginalSize int U?Zq6_M&
SELECT @OriginalSize = size 6<QQ@5_
FROM sysfiles kVMg 1I@
WHERE name = @LogicalFileName )Nw8O{\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + YK'<NE3 4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + n b?lTX~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .|70;
FROM sysfiles |0b`fOS
WHERE name = @LogicalFileName i[3'ec3
CREATE TABLE DummyTrans [}=B8#Jl-C
(DummyColumn char (8000) not null) ![=yi
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DECLARE @Counter INT, f}P3O3Yv&
@StartTime DATETIME, 6A-|[(NS
@TruncLog VARCHAR(255) 904}Jh,
SELECT @StartTime = GETDATE(), G5 WVr$
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' |u<7?)mp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wlqksG[B
EXEC (@TruncLog) ^6V[=!& H
-- Wrap the log if necessary. yNBfUj -L
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .Yn_*L+4*
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) kn4`Fa;)O
AND (@OriginalSize * 8 /1024) > @NewSize Bj;'qB>3
BEGIN -- Outer loop. {4Cmu;u
SELECT @Counter = 0 583|blL
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) '-~~-}= sJ
BEGIN -- update 1>h]{%I
INSERT DummyTrans VALUES ('Fill Log') u&7[n_
DELETE DummyTrans zRr*7G
SELECT @Counter = @Counter + 1 #)O65GI
END aX'*pK/-
EXEC (@TruncLog) _Y;W0Z
END %P|/A+Mg"
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8(~h"]`!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + hHnYtq
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' }19\.z&J
FROM sysfiles \_f(M|
WHERE name = @LogicalFileName n{mfn*r.
DROP TABLE DummyTrans U'bEL^Jf
SET NOCOUNT OFF ?Z/V~,
8、说明:更改某个表 b3,
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exec sp_changeobjectowner 'tablename','dbo' .#8 JCY
9、存储更改全部表 /y}xX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 9rf)gU3{+L
@OldOwner as NVARCHAR(128), !%c\N8<>GD
@NewOwner as NVARCHAR(128) )Ql%r?(F+
AS Vt#.eL)Ee
DECLARE @Name as NVARCHAR(128) e(t\g^X
DECLARE @Owner as NVARCHAR(128) @:#eb1<S
DECLARE @OwnerName as NVARCHAR(128) p<"m[Dt]
DECLARE curObject CURSOR FOR /a4{?? #e
select 'Name' = name, XW]tnrs
'Owner' = user_name(uid) (O3nL.
from sysobjects -uf|w?
where user_name(uid)=@OldOwner F={a;Dvrn
order by name UP,c |
OPEN curObject /PIcqg
FETCH NEXT FROM curObject INTO @Name, @Owner }o`76rDN
WHILE(@@FETCH_STATUS=0) (f"4,b^]
BEGIN yY q,*<G
if @Owner=@OldOwner [{,1=AB
begin MQ6KN(?\ZL
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0 @oJFJrO
exec sp_changeobjectowner @OwnerName, @NewOwner 2J BR)P
end 4,DeHJjAlE
-- select @name,@NewOwner,@OldOwner uVrd i?3
FETCH NEXT FROM curObject INTO @Name, @Owner
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END ( a#BV}=
close curObject v.qrz"98-
deallocate curObject &tj!*k'
GO 4.t-i5
10、SQL SERVER中直接循环写入数据 ^ [@,
declare @i int /%^#8<=|U
set @i=1
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while @i<30 N~'c_l
begin >z@0.pN]7
insert into test (userid) values(@i) jse&DQ
set @i=@i+1 S)@j6(HC4
end A*BeR0(
小记存储过程中经常用到的本周,本月,本年函数 Cw&KVw*
Dateadd(wk,datediff(wk,0,getdate()),-1) xJ.M;SF4
Dateadd(wk,datediff(wk,0,getdate()),6) utV_W&
Dateadd(mm,datediff(mm,0,getdate()),0) A.w.rVDD
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) sFRQe]zCcP
Dateadd(yy,datediff(yy,0,getdate()),0) )9]P MA?u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1$h,m63)
上面的SQL代码只是一个时间段 vnuN6M{
Dateadd(wk,datediff(wk,0,getdate()),-1) Ig{0Z">
Dateadd(wk,datediff(wk,0,getdate()),6) nX8v+:&}
就是表示本周时间段. c-sfg>0 ^
下面的SQL的条件部分,就是查询时间段在本周范围内的: b&U62iq
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) c7H^$_^ =
而在存储过程中 #Gi$DMW
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) pMM8-R'W-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]7A'7p$Y