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。 >J}n@MZ
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一、基础 ^
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1、说明:创建数据库 dPx<Dz;
CREATE DATABASE database-name DAnb.0
2、说明:删除数据库 )_v\{N
drop database dbname <s8?
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3、说明:备份sql server ^QAiySR`0
--- 创建 备份数据的 device fhV0S>*<
USE master z8[H:W#G
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <{/;1Dru
--- 开始 备份 ch>Vv"G>
BACKUP DATABASE pubs TO testBack +SQjX7]%
4、说明:创建新表 kV ,G,wo
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h1XMx'}B
根据已有的表创建新表: (.1 rtj
A:create table tab_new like tab_old (使用旧表创建新表) Q)S>VDLA
B:create table tab_new as select col1,col2... from tab_old definition only `x UG|
5、说明:删除新表 3%R{"Q"
drop table tabname +%wWSZ<#
6、说明:增加一个列 lKEX"KQ!
Alter table tabname add column col type ~pevU`}Uqc
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。 ^5]uBOv
7、说明:添加主键: Alter table tabname add primary key(col) gKN}Of@^1
说明:删除主键: Alter table tabname drop primary key(col) L"foL
8、说明:创建索引:create [unique] index idxname on tabname(col....) C4{\@v}t
删除索引:drop index idxname ISS\uj63M
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement :Sc8PLT
删除视图:drop view viewname %)axGbZG;
10、说明:几个简单的基本的sql语句 OB6J.dF[%
选择:select * from table1 where 范围 G*\abL
插入:insert into table1(field1,field2) values(value1,value2) ZCQ<%f
删除:delete from table1 where 范围 90s;/y(
更新:update table1 set field1=value1 where 范围 T|@#w%c''
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %5h^`lp
排序:select * from table1 order by field1,field2 [desc] #+"4&:my
总数:select count as totalcount from table1 85D^@{
求和:select sum(field1) as sumvalue from table1 q[G/}
平均:select avg(field1) as avgvalue from table1 #%^\\|'z
最大:select max(field1) as maxvalue from table1 =4zNo3IvL+
最小:select min(field1) as minvalue from table1 vJRnBq+y
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11、说明:几个高级查询运算词 :)p)=c8%
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A: UNION 运算符 EqnpMHF
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。 {pDTy7!Hs
B: EXCEPT 运算符 UP;Q= 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。 ivzAlwP
C: INTERSECT 运算符 hOPe^e"
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。 kG1;]1tT#
注:使用运算词的几个查询结果行必须是一致的。 [q-;/ed
12、说明:使用外连接 M!gBmQZ1
A、left outer join: mz\NFC<
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。 R-pH Quu3
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 gg-};0P-
B:right outer join: ?MC(}dF0
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。 Xsd$*F@<
C:full outer join: \+k, :8s/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ^/>Wr'w
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二、提升 d/{Q
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o]Wz6L
法一:select * into b from a where 1<>1 (kIz
法二:select top 0 * into b from a pI7Ssvi^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) X9fNGM1
insert into b(a, b, c) select d,e,f from b; ,+tPRkwA^
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 3J%V%}mD
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 q2e]3{l3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bj@xqAGl
4、说明:子查询(表名1:a 表名2:b) Q,.By&
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 3;*z3;#}
5、说明:显示文章、提交人和最后回复时间 /_V'DJV
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b dv;9QCc'
6、说明:外连接查询(表名1:a 表名2:b) P:sAqvH6
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +z\\VD
7、说明:在线视图查询(表名1:a ) I>A^I
select * from (SELECT a,b,c FROM a) T where t.a > 1; ]gu1#
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 6Rcua<;2P
select * from table1 where time between time1 and time2 ~TDzq -U)
select a,b,c, from table1 where a not between 数值1 and 数值2 4`nqAX~'f
9、说明:in 的使用方法 ?6i;)eIOI
select * from table1 where a [not] in ('值1','值2','值4','值6') 3AURzU
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {6'*Phw
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) W`$[j0
11、说明:四表联查问题: 0
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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 ..... .f>,6?
12、说明:日程安排提前五分钟提醒 I:#Ok+
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 :pwa{P
13、说明:一条sql 语句搞定数据库分页 3bH~';<
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 +?;j&p
14、说明:前10条记录 {h#6z>p"u2
select top 10 * form table1 where 范围 M% @
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.) k oM]S+1
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) !k,<|8(0
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 R<_?W#$j
(select a from tableA ) except (select a from tableB) except (select a from tableC) d.`&0
17、说明:随机取出10条数据 tBseqS3<
select top 10 * from tablename order by newid() a/~29gW8E\
18、说明:随机选择记录
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select newid() Gn59yG!4
19、说明:删除重复记录 CtM'L
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w
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20、说明:列出数据库里所有的表名 gN?0m4[$i
select name from sysobjects where type='U' lEHwZ<je
21、说明:列出表里的所有的 /xySwSmh3
select name from syscolumns where id=object_id('TableName') 3 > |uF
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。 -Q$b7*"z(
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 $jG4pPG
显示结果: O)uOUB
type vender pcs 1}!L][(
电脑 A 1 H`-=?t
电脑 A 1 /7gi/uh~-(
光盘 B 2 ~:[!Uyp0b
光盘 A 2 D`VFf\7
手机 B 3 uEx9-,!
手机 C 3 "jR]MZ
23、说明:初始化表table1 T C8`JU=wV
TRUNCATE TABLE table1 BwxnDe G)
24、说明:选择从10到15的记录 Jx$iwu
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc B'}"AC"
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 zAs&%OjG
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 5M:D?9E+
如: Qz+sT6js-
if @strWhere !='' r`6:Q&&
begin -7%X]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #.ct5
end b5pMq$UVL
else *Qkc[XHqy
begin {)@D`{$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' {%b
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end SEM8`lnu
我们可以直接写成 lY'N4x7n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere pu4,0bw
2、收缩数据库 WUEHB
--重建索引 nY_?Jq
DBCC REINDEX |P~;C6sf
DBCC INDEXDEFRAG f:woP7FP
--收缩数据和日志 uzBz}<M=
DBCC SHRINKDB WVX`<
DBCC SHRINKFILE gU1 #`r>[)
3、压缩数据库 rzeLx Wt
dbcc shrinkdatabase(dbname) `rb>K
4、转移数据库给新用户以已存在用户权限 j6g@tx^)'
exec sp_change_users_login 'update_one','newname','oldname' Vz%OV}\
go 2.lgT|p
5、检查备份集 3[IJhR[
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' \we\0@v
6、修复数据库 KE}H&1PjU
ALTER DATABASE [dvbbs] SET SINGLE_USER mdbp8,O
GO +dW|^I{H}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK L":bI&V?:
GO 'g)n1 {
ALTER DATABASE [dvbbs] SET MULTI_USER / T
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GO Ev9> @~^
7、日志清除 :c.JhE3D
SET NOCOUNT ON 9YN?
DECLARE @LogicalFileName sysname, C~4PE>YtTv
@MaxMinutes INT, NwlU%{7W6
@NewSize INT _\8qwDg"#e
USE tablename -- 要操作的数据库名 r8/l P}(F
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 NHQF^2 \\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. G"dS+,Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,0N94pKy
-- Setup / initialize !>$4]FkV
DECLARE @OriginalSize int ;xYNX
SELECT @OriginalSize = size :aAEJ
FROM sysfiles Uh6 '$0
WHERE name = @LogicalFileName d_z59
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 'LE"#2Hu
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + D=r))
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 39i9wrP
FROM sysfiles =aG xg57
WHERE name = @LogicalFileName jXg
CREATE TABLE DummyTrans NH A 5e<
(DummyColumn char (8000) not null) DKL@wr}8
DECLARE @Counter INT, 1bnBji
@StartTime DATETIME, BU Z
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@TruncLog VARCHAR(255) i[jJafAcN
SELECT @StartTime = GETDATE(), .Ajzr8P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' u.XQ&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) *e>]~Z,
EXEC (@TruncLog) XOP"Px@
-- Wrap the log if necessary. c}Z6V1]QP
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired yay<GP?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8IQtz2
AND (@OriginalSize * 8 /1024) > @NewSize |SZo'
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BEGIN -- Outer loop. "/Pjjb:2
SELECT @Counter = 0 =T?}Nt
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) :M3oUE{
BEGIN -- update thlY0XCq,%
INSERT DummyTrans VALUES ('Fill Log') ;|T!#@j
DELETE DummyTrans &)d$t'7p
SELECT @Counter = @Counter + 1 VosZJv=
END f|7\DeY9U
EXEC (@TruncLog) #N(= 3Cj
END 4*n#yVb/
SELECT 'Final Size of ' + db_name() + ' LOG is ' + +n0r0:z0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + p{A}pnjf
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' '@|_OmcY
FROM sysfiles 1$/MrPT(b
WHERE name = @LogicalFileName &F
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DROP TABLE DummyTrans zE T^T5>:
SET NOCOUNT OFF B(g_Gm<
8、说明:更改某个表 Q#I"_G&{
exec sp_changeobjectowner 'tablename','dbo' C*=Xk/0
9、存储更改全部表 _9 .(a
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch r|Z3$J{^"
@OldOwner as NVARCHAR(128), `:8J46or
@NewOwner as NVARCHAR(128) pIV-kI:w
AS olB)p$aH#
DECLARE @Name as NVARCHAR(128) f
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DECLARE @Owner as NVARCHAR(128) z
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DECLARE @OwnerName as NVARCHAR(128) B(a-k?
DECLARE curObject CURSOR FOR ^ 2GHe<Y
select 'Name' = name, jd]s<C3o
'Owner' = user_name(uid) "xI"
from sysobjects aimarU
where user_name(uid)=@OldOwner qU2~fNY
order by name k %e^kej
OPEN curObject {R<Ea
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FETCH NEXT FROM curObject INTO @Name, @Owner >zsid:
WHILE(@@FETCH_STATUS=0)
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BEGIN (
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if @Owner=@OldOwner H`bSYjgM!
begin K%<j=c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g6@Fp7T
exec sp_changeobjectowner @OwnerName, @NewOwner c .3ZXqpI;
end ,u }XWV
-- select @name,@NewOwner,@OldOwner ^H{R+}
FETCH NEXT FROM curObject INTO @Name, @Owner (/!r(#K0,'
END #4MBoN(3
close curObject <9E0iz+j
deallocate curObject ptatzp]c#
GO 5Wyz=+?m|
10、SQL SERVER中直接循环写入数据 qf@q]wtar
declare @i int 8KB>6[H!wE
set @i=1 sQ6}\
while @i<30 <~}7Mxn%x@
begin M#"524Nz
insert into test (userid) values(@i) 4a0:2 kIKa
set @i=@i+1 7Dzuii?1
end !-2R;yo12
小记存储过程中经常用到的本周,本月,本年函数 'j^xbikr
Dateadd(wk,datediff(wk,0,getdate()),-1) ]V %.I_
Dateadd(wk,datediff(wk,0,getdate()),6) D0k
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Dateadd(mm,datediff(mm,0,getdate()),0) e0@6Pd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n55Pv3}C
Dateadd(yy,datediff(yy,0,getdate()),0) M` q?Fk
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) f.aSKQD
上面的SQL代码只是一个时间段 q{s(.Uq$&
Dateadd(wk,datediff(wk,0,getdate()),-1) 0q>P~]Ow
Dateadd(wk,datediff(wk,0,getdate()),6) D']ZlB'K
就是表示本周时间段. bwVPtu`
下面的SQL的条件部分,就是查询时间段在本周范围内的: yKYUsp
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Qy<[7
而在存储过程中 gmIqT
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) EXP%Mk/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U4m9e|/H;z