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。 +wts 7,3
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一、基础 V* Qe5j9
1、说明:创建数据库 {jG.=}/Dk
CREATE DATABASE database-name !c_u-&b)
2、说明:删除数据库 Z3n~&!
drop database dbname qp1\I$Y
3、说明:备份sql server d
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--- 创建 备份数据的 device )[ w&C_>]
USE master {tmKCG
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' l qXc
--- 开始 备份 o#dcD?^
BACKUP DATABASE pubs TO testBack NE[y|/
4、说明:创建新表 Z*h ;e;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |=,83,a
根据已有的表创建新表: 8qmknJC
A:create table tab_new like tab_old (使用旧表创建新表) o]p#%B?mZ
B:create table tab_new as select col1,col2... from tab_old definition only To^#
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5、说明:删除新表 sr4jQo
drop table tabname _2; ^v`[
6、说明:增加一个列 [lOf|^9
Alter table tabname add column col type *k!(ti[
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 +0U#.|?
7、说明:添加主键: Alter table tabname add primary key(col) ,P!D-MN$V
说明:删除主键: Alter table tabname drop primary key(col) y-<$bA[K~
8、说明:创建索引:create [unique] index idxname on tabname(col....) m1i4 ,
删除索引:drop index idxname ~r PYJ
注:索引是不可更改的,想更改必须删除重新建。 k~R{Y~W!!
9、说明:创建视图:create view viewname as select statement |""=)-5N
删除视图:drop view viewname E0T&GR@.
10、说明:几个简单的基本的sql语句 {Evcc+Eq
选择:select * from table1 where 范围 yz8-&4YRNd
插入:insert into table1(field1,field2) values(value1,value2) Ia'x]#~
删除:delete from table1 where 范围 lD-V9
更新:update table1 set field1=value1 where 范围 FQ0KUb}0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =g >.X9lr
排序:select * from table1 order by field1,field2 [desc] "0b?+ 3_{G
总数:select count as totalcount from table1 `,Xb8^M2
求和:select sum(field1) as sumvalue from table1 prwC>LE
平均:select avg(field1) as avgvalue from table1 wLpkUa
最大:select max(field1) as maxvalue from table1 TbMdQbj}
最小:select min(field1) as minvalue from table1 hR!}u}ECd
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11、说明:几个高级查询运算词 .#sz|0
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A: UNION 运算符 epn#qeX
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 FOc|*>aKP
B: EXCEPT 运算符 eN2dy-0
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 uC- A43utv
C: INTERSECT 运算符 Z(KmS(
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 E2kW=6VO>|
注:使用运算词的几个查询结果行必须是一致的。 {K<uM'ww>
12、说明:使用外连接 &{ DR6
A、left outer join: 8^8>qSD1
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 <{E;s)hD?
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Wgav>7!9
B:right outer join: R$Zv0a&
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。 sTt9'P`
C:full outer join: l6V%"Lo/)
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。 P`p6J8}4
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二、提升 Y 5Qb4Sa
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +mivqR~{{
法一:select * into b from a where 1<>1 $4DFgvy$
法二:select top 0 * into b from a XpR.rq$]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :-w@^mli
insert into b(a, b, c) select d,e,f from b; ]}p2Tp;1
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) &}>|5>cJu
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 GXarUj s
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]vRVo6@ k
4、说明:子查询(表名1:a 表名2:b) C5>{Q:.`e'
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) sk~ za
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 YfTd
6、说明:外连接查询(表名1:a 表名2:b) mgo'MW\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F# jCEq
7、说明:在线视图查询(表名1:a ) 6 lN?) <uQ
select * from (SELECT a,b,c FROM a) T where t.a > 1; |)28=Z|Z
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 W8Ke1(ws&
select * from table1 where time between time1 and time2 xR0~S
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select a,b,c, from table1 where a not between 数值1 and 数值2 jAA'hA
9、说明:in 的使用方法 tU9rCL:P
select * from table1 where a [not] in ('值1','值2','值4','值6') $|>6z_3%
10、说明:两张关联表,删除主表中已经在副表中没有的信息 nwY2BIB
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pZc9q8j3
11、说明:四表联查问题: UN,<6D3\b
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... -$AjD?;
12、说明:日程安排提前五分钟提醒 uOyLC<I/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <FXQxM5"
13、说明:一条sql 语句搞定数据库分页 &W&7bZ$;
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% :WLQo
14、说明:前10条记录 A28ZSL
select top 10 * form table1 where 范围 F(T=WR].o
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.) vs5
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) zzulVj*
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 j09mI$2y67
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 sqm%iyC=q
select top 10 * from tablename order by newid() p+u{W"I`
18、说明:随机选择记录 y&n1 Nj]^
select newid() ~| X99?P
19、说明:删除重复记录 ^JYF1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Ln"+nKr
20、说明:列出数据库里所有的表名 P Xyyyir{
select name from sysobjects where type='U' 5"76R
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21、说明:列出表里的所有的 <ol$-1l#9
select name from syscolumns where id=object_id('TableName') Iu=pk@*O
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。 ==jkp
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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 e1f^:C
显示结果: uf{SxEa
type vender pcs :d!i[W*
电脑 A 1 jK ?
电脑 A 1 UMHuIA:%U
光盘 B 2 wZ
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光盘 A 2 x]yHBc
手机 B 3 r?Ev.m
手机 C 3 w3>Y7vxiz`
23、说明:初始化表table1 b&hF')_UOz
TRUNCATE TABLE table1 ,Ut!u)
24、说明:选择从10到15的记录 ~NNaLl
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?RrC~7~
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三、技巧 Apw-7*/
1、1=1,1=2的使用,在SQL语句组合时用的较多 30gZ_8C>}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, IkE'_F
如: t<KEx^gb
if @strWhere !='' FM@W>+
begin (HTk;vbZm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere MJ*oeI!.=
end TkoCyD9
else %8z+R m,Ot
begin !0d9<SVC
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :5q*46n
end {
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我们可以直接写成 g,z&{pZch
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere _If@#WnoyA
2、收缩数据库 6):sO/es
--重建索引 45!`g+)
DBCC REINDEX \fQgiX
DBCC INDEXDEFRAG eog,EP"a8Y
--收缩数据和日志 9X^-)G>
DBCC SHRINKDB OFPd6,(E
DBCC SHRINKFILE HzO0K=Z=R0
3、压缩数据库 ;M(ehX
dbcc shrinkdatabase(dbname) W4] 0qp`\
4、转移数据库给新用户以已存在用户权限 +kdU%Sm
exec sp_change_users_login 'update_one','newname','oldname' 'Rar>oU
go sN[@mAoH
5、检查备份集 RIVN>G[;L
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' < 8W:ij.`
6、修复数据库 D$^7Xhk
ALTER DATABASE [dvbbs] SET SINGLE_USER :ayO+fr#
GO "78cl*sD
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 0,i+
GO JY,l#?lM{
ALTER DATABASE [dvbbs] SET MULTI_USER E%v[7 ST
GO {(zL"g46
7、日志清除 enfu%"(K)
SET NOCOUNT ON :XZJx gx
DECLARE @LogicalFileName sysname, (x*2BEn|
@MaxMinutes INT, S+\Mt+o
@NewSize INT CBgFB-!qpe
USE tablename -- 要操作的数据库名 ,~68~_)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 V'|g
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \Jj'60L^
@NewSize = 1 -- 你想设定的日志文件的大小(M) ^
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-- Setup / initialize u
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DECLARE @OriginalSize int 7E84@V[\
SELECT @OriginalSize = size !nD[hI8P
FROM sysfiles mm9S#Ya
WHERE name = @LogicalFileName 5;KT-(q~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {10+(Vl
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + l#(g&x6J
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' OKNs (H
FROM sysfiles jzOMjz~:)
WHERE name = @LogicalFileName zw;(:fgY#
CREATE TABLE DummyTrans ]8j5Ou6#y
(DummyColumn char (8000) not null) [>QsMUvak
DECLARE @Counter INT, /URj$|
@StartTime DATETIME, $F'~^2
@TruncLog VARCHAR(255) .dq.F#2B;
SELECT @StartTime = GETDATE(), UqQZ
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' L bK1CGyA
DBCC SHRINKFILE (@LogicalFileName, @NewSize) TbUkqABm
EXEC (@TruncLog) Q?'W >^*J
-- Wrap the log if necessary. ieg PEb
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K Qy\l+\gM
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) &[\arwe)
AND (@OriginalSize * 8 /1024) > @NewSize }t{^*(
BEGIN -- Outer loop. bsS|!KT
SELECT @Counter = 0 !c;p4B)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
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BEGIN -- update P_}_D{G
INSERT DummyTrans VALUES ('Fill Log') kys-~&@+
DELETE DummyTrans o0v m?CL#
SELECT @Counter = @Counter + 1 ToCfLJ?{
END "+OMo-<K7
EXEC (@TruncLog) JSP8Lu"n
END 7PPsEU:rf
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2FtEt+A+'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + .
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ry=[:\Z~
FROM sysfiles T%b^|="@
WHERE name = @LogicalFileName O4+w2'.,
DROP TABLE DummyTrans 7VD7di=D
SET NOCOUNT OFF nFOG=>c}
8、说明:更改某个表 R}YryzV5
exec sp_changeobjectowner 'tablename','dbo' "alO"x8t
9、存储更改全部表 J~ rC
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch NQ{Z
@OldOwner as NVARCHAR(128), S 2` ;7
@NewOwner as NVARCHAR(128) Tl{r D(D
AS 'Z%aBCM
DECLARE @Name as NVARCHAR(128) G&B}jj
DECLARE @Owner as NVARCHAR(128) {;gWn'aq
DECLARE @OwnerName as NVARCHAR(128) DD3yl\#,
DECLARE curObject CURSOR FOR O[J+dWyp
select 'Name' = name, x=<>%m5R
'Owner' = user_name(uid) F>nrV
from sysobjects P =Gb
where user_name(uid)=@OldOwner k0=y_7
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order by name ~|jy$*m4A
OPEN curObject :D7!6}%
FETCH NEXT FROM curObject INTO @Name, @Owner >I;#BE3
WHILE(@@FETCH_STATUS=0) T"lqPbK
BEGIN ^OsUWhkV
if @Owner=@OldOwner iC\=U
begin ~H."{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) f)fw87UPc
exec sp_changeobjectowner @OwnerName, @NewOwner |#,W3Ik(l
end 66;O 3g'
-- select @name,@NewOwner,@OldOwner Vi~+C@96
FETCH NEXT FROM curObject INTO @Name, @Owner rx)Q]
END 5.;$9~d
close curObject )W3l{T(
deallocate curObject KPrxw }P
GO 2(x KE_|
10、SQL SERVER中直接循环写入数据 8hV:bz"
declare @i int 'KrkCA
set @i=1 ~UFsi VpL
while @i<30 NV ~i4R*#
begin NX/)Z&Fx:
insert into test (userid) values(@i) !7|9r$
set @i=@i+1 G*V
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end Jx7^|A
小记存储过程中经常用到的本周,本月,本年函数 `84yGXLK
Dateadd(wk,datediff(wk,0,getdate()),-1) <FLc0s
Dateadd(wk,datediff(wk,0,getdate()),6) )^3655mb
Dateadd(mm,datediff(mm,0,getdate()),0) [X\2U4
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) Tl-B[CT
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >@W#@W*I@
上面的SQL代码只是一个时间段 81C?U5
Dateadd(wk,datediff(wk,0,getdate()),-1) -': tpJk
Dateadd(wk,datediff(wk,0,getdate()),6) an@Ue7
就是表示本周时间段. NyNu1V$
下面的SQL的条件部分,就是查询时间段在本周范围内的: {%dQV#'c
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) o$;x[US
而在存储过程中 1k(*o.6
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) OC.@C}u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) M3;B]iRQD