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。 %z"$?Iv
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一、基础 9,"gXsvx(
1、说明:创建数据库 &[yYgfsp
CREATE DATABASE database-name ]2|KG3t
2、说明:删除数据库 4]Gm4zO
drop database dbname |>>^Mol
3、说明:备份sql server D (e,R9hPU
--- 创建 备份数据的 device XZ3M~cDq
USE master d/YQ6oKU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h_g"F@
--- 开始 备份 z@jKzyq
BACKUP DATABASE pubs TO testBack 7&L8zl|K
4、说明:创建新表 >Tn[CgH]7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) KQ(S\
根据已有的表创建新表: S>"C}F$X
A:create table tab_new like tab_old (使用旧表创建新表) @]EdUzzKq
B:create table tab_new as select col1,col2... from tab_old definition only @ W q8AFo
5、说明:删除新表 @9k/od@mW
drop table tabname \Z~
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6、说明:增加一个列 l9H-N*Wx
Alter table tabname add column col type vJ&35nF&
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。 hWbjA[a/
7、说明:添加主键: Alter table tabname add primary key(col) avXBCvP+h
说明:删除主键: Alter table tabname drop primary key(col) I6S>*V
8、说明:创建索引:create [unique] index idxname on tabname(col....) !yKrA|w1
删除索引:drop index idxname QP@@h4J^
注:索引是不可更改的,想更改必须删除重新建。 +5kQ;D{+
9、说明:创建视图:create view viewname as select statement *$mb~k^R
删除视图:drop view viewname :U @L$
10、说明:几个简单的基本的sql语句 Jr>Nc}!U
选择:select * from table1 where 范围 ^{E_fQJX
插入:insert into table1(field1,field2) values(value1,value2) f
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删除:delete from table1 where 范围 s(MdjWw
更新:update table1 set field1=value1 where 范围 90H/Txq
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! :`4LV
排序:select * from table1 order by field1,field2 [desc] >R\@W(-g`
总数:select count as totalcount from table1 |Y2n6gkH[
求和:select sum(field1) as sumvalue from table1 KT<N
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平均:select avg(field1) as avgvalue from table1 ItAC=/(d
最大:select max(field1) as maxvalue from table1 w7<4D,hk
最小:select min(field1) as minvalue from table1 GzT?I
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11、说明:几个高级查询运算词 1O90 ]c0
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A: UNION 运算符 +]Z*_?j9{
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。 t
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B: EXCEPT 运算符 ;;EFiaA
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。 owO&[D/
C: INTERSECT 运算符 p\]rxtm
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。 1}CJ&
注:使用运算词的几个查询结果行必须是一致的。 gf8~Zlq4v
12、说明:使用外连接 mDWRYIuN
A、left outer join: Y@b|/+
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。 `0R>r7f)H
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 b1Ba}
B:right outer join: /j\.~=,_
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。 ` ^z
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C:full outer join: j~hvPlho
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。 ]\3<UL
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二、提升 ~y ?v
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) \@6V{y'Zo
法一:select * into b from a where 1<>1 8BnsYy)j
法二:select top 0 * into b from a YsRq.9Mr
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) A5G@u}YS5
insert into b(a, b, c) select d,e,f from b; )/bv@Am
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) Ek '%%%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )Qo^Mz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. }9+Vf'u|l
4、说明:子查询(表名1:a 表名2:b) ,Fu[o6x<^
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)
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5、说明:显示文章、提交人和最后回复时间 !nF.whq
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b j7VaaA
6、说明:外连接查询(表名1:a 表名2:b) (T.g""N~`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^3Z~RK\}
7、说明:在线视图查询(表名1:a ) pEb/ yIT"
select * from (SELECT a,b,c FROM a) T where t.a > 1; T<mP.T,$!
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 *o=( w5
select * from table1 where time between time1 and time2 qqu]r
select a,b,c, from table1 where a not between 数值1 and 数值2 <mQ9YO#
9、说明:in 的使用方法 &tlU.Whk+
select * from table1 where a [not] in ('值1','值2','值4','值6') tz%H1`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 z*N%kcw"
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Z$K[e
11、说明:四表联查问题: X@~R<
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 ..... $oi8<8Y
12、说明:日程安排提前五分钟提醒 Z&GjG6t
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 hOm0ND?;1
13、说明:一条sql 语句搞定数据库分页 YUlH5rO3
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 D#X&gE
14、说明:前10条记录 (i]0IYMXy*
select top 10 * form table1 where 范围 z+Ej`$E{lD
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.) {=P}c:iW
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2:6lr4{uY
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 I"WmDC`1
(select a from tableA ) except (select a from tableB) except (select a from tableC) kM(,8j
17、说明:随机取出10条数据 qK&h$;~*y
select top 10 * from tablename order by newid() &LhR0A
18、说明:随机选择记录 ,{#L i
select newid() 0}$R4<"{Y>
19、说明:删除重复记录 H$xUOqL
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =K9-
20、说明:列出数据库里所有的表名 MAgoxq~;V
select name from sysobjects where type='U' -qB{TA-.\
21、说明:列出表里的所有的 K- TLzoYA
select name from syscolumns where id=object_id('TableName') 3MHByT%
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。 R=L-Ulhk
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 h{e?Fl
显示结果: twql)lbx
type vender pcs qB3=wFI
电脑 A 1 d-#yN:}0
电脑 A 1 &t74T"(d
光盘 B 2 VCUsvhI
光盘 A 2 AH#Dk5#G
手机 B 3 FC8#XZp
手机 C 3 Odbm"Y
23、说明:初始化表table1 zUJPINDb
TRUNCATE TABLE table1 D (">bR)1
24、说明:选择从10到15的记录 Jrx]/CM
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j.29nJ
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三、技巧 b!z=:
1、1=1,1=2的使用,在SQL语句组合时用的较多 _RG2I)P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dijHi
如: bO+L#Kf
if @strWhere !='' R|!4klb
begin N-Sjd%Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 2?c%<_jPA
end jp#/]>(9Z
else fZ pUnc
begin B..> *Xb
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *6]_ 6xO
end [vcSt5R=
我们可以直接写成 uSNlI78D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4,7W*mr3(
2、收缩数据库 `FIS2sl/
--重建索引 <f@
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DBCC REINDEX ZrDr/Q~
DBCC INDEXDEFRAG A55F *d
--收缩数据和日志 A{\!nq_~N
DBCC SHRINKDB ||rZ+<
DBCC SHRINKFILE eu?DSad
3、压缩数据库 [J43]
dbcc shrinkdatabase(dbname) Zex`n:Wl?j
4、转移数据库给新用户以已存在用户权限 4tFnZ2x
exec sp_change_users_login 'update_one','newname','oldname' >W=^>8u
go 0|`iop%(n
5、检查备份集 Ly`FU)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qUG)+~g`
6、修复数据库 QQX7p!~E
ALTER DATABASE [dvbbs] SET SINGLE_USER {3\{aZ8)
GO XM?C7/^k
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 3qrjb]E%}
GO $WZHkV
ALTER DATABASE [dvbbs] SET MULTI_USER Z`{GjV3%wH
GO Xa&0j&AH
7、日志清除 604^~6
SET NOCOUNT ON C)+%9Edg
DECLARE @LogicalFileName sysname, Cg%}=
@MaxMinutes INT, w:@W/e*9N
@NewSize INT jg=}l1M"
USE tablename -- 要操作的数据库名 UJrN+RtL
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 LKu
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. #:}mi;{
@NewSize = 1 -- 你想设定的日志文件的大小(M) (Z at|R.F
-- Setup / initialize hE}y/A[
DECLARE @OriginalSize int 9I*`~il>{
SELECT @OriginalSize = size NpF)|Ppb{
FROM sysfiles P<IZ%eS3B
WHERE name = @LogicalFileName 5t[7taLX\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ya/pn
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0tP{K
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' H@ .1cO
FROM sysfiles .jbT+hhM
WHERE name = @LogicalFileName qJ<Ghd`8v
CREATE TABLE DummyTrans Z}$1~uyw
(DummyColumn char (8000) not null) ^h"F\vIpV
DECLARE @Counter INT, 2)jf~!o)Z
@StartTime DATETIME, MHAWnH8
@TruncLog VARCHAR(255) #i[V{J8.p
SELECT @StartTime = GETDATE(), MD=!a5'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' cW\Y1=Gv|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) hquN+eIDH
EXEC (@TruncLog) M0"}>`1lJ
-- Wrap the log if necessary. Xa/]}
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6YYDp&nqEj
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aUEnQ%YU"
AND (@OriginalSize * 8 /1024) > @NewSize #l-/!j
BEGIN -- Outer loop. ? ]hS^&
SELECT @Counter = 0 vK8!V7o~h%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) z]R)Bh
BEGIN -- update <'z.3@D
INSERT DummyTrans VALUES ('Fill Log') xs$-^FnD
DELETE DummyTrans 5q{
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SELECT @Counter = @Counter + 1 ny[\yj4F
END YEhPAQNj
EXEC (@TruncLog) eLN[`hJ
END >Gxh=**F
SELECT 'Final Size of ' + db_name() + ' LOG is ' + %vjfAdC
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + c"^g*i2&0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xX2/uxi8
FROM sysfiles k= oCpXq^
WHERE name = @LogicalFileName s,;L6nX"
DROP TABLE DummyTrans 5D`!Tu3
SET NOCOUNT OFF R(<_p"9(
8、说明:更改某个表 =fy'w3m
exec sp_changeobjectowner 'tablename','dbo' d/xGo[?$
9、存储更改全部表 !eGUiE=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ='\E+*[$I
@OldOwner as NVARCHAR(128), .*g^
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@NewOwner as NVARCHAR(128) *|&&3&7
AS .Sjg
DECLARE @Name as NVARCHAR(128) WO"<s{v
DECLARE @Owner as NVARCHAR(128) gatxvR7H
DECLARE @OwnerName as NVARCHAR(128) $5Tjo
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DECLARE curObject CURSOR FOR [HSN*LXe
select 'Name' = name, JD{AwE@Ro
'Owner' = user_name(uid) P/doNv}iG
from sysobjects EF[I@voc
where user_name(uid)=@OldOwner (pkq{: Fs
order by name t
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OPEN curObject G;v3kGn
FETCH NEXT FROM curObject INTO @Name, @Owner p#tbN5i[{7
WHILE(@@FETCH_STATUS=0) 2qfKDZ9f^
BEGIN DjQgF=;
if @Owner=@OldOwner RS
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begin QVPJ$~x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) '=]|"
exec sp_changeobjectowner @OwnerName, @NewOwner 1ppU
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end ]m"6a-,`
-- select @name,@NewOwner,@OldOwner d m$iiRY
FETCH NEXT FROM curObject INTO @Name, @Owner [rtMx8T
END k|[86<&[
close curObject .[>UkM0
deallocate curObject >'2=3L^Q
GO 7DCu#Y[
10、SQL SERVER中直接循环写入数据 @8'LI8 \/
declare @i int iVqXf;eB!5
set @i=1 4dI=
while @i<30 C9"yu&l
begin ()%;s2>F
insert into test (userid) values(@i) &(,-:"{pNR
set @i=@i+1 *4RL
end xzOM\Nq?O
小记存储过程中经常用到的本周,本月,本年函数 `Fs- z
Dateadd(wk,datediff(wk,0,getdate()),-1) c-bTf$6}
Dateadd(wk,datediff(wk,0,getdate()),6) R:t
Dateadd(mm,datediff(mm,0,getdate()),0) /H<tv5mXJ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ps@{1Rn1
Dateadd(yy,datediff(yy,0,getdate()),0) ck K9@RQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V( SRw
上面的SQL代码只是一个时间段 l6k.`1.In
Dateadd(wk,datediff(wk,0,getdate()),-1) N2e]S8-
Dateadd(wk,datediff(wk,0,getdate()),6) P~ 7p~ke
就是表示本周时间段. (`FY{]Wz!
下面的SQL的条件部分,就是查询时间段在本周范围内的: - {|
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) UA}N
而在存储过程中 |t&gyj
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vFgX]&bE
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `beU2N