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。 $w!; ~s
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一、基础 BCN<l +u
1、说明:创建数据库 QJ1_LJ4)a
CREATE DATABASE database-name u
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2、说明:删除数据库 &aD]_+b
drop database dbname svki=GD_(.
3、说明:备份sql server 9nIBs{`/Ac
--- 创建 备份数据的 device Q(Uj5 aX
USE master NgH"jg-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' (5AgI7I,
--- 开始 备份
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BACKUP DATABASE pubs TO testBack ,jVj9m
4、说明:创建新表 =pHWqGOD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) p<hV7x-{
根据已有的表创建新表: P){F2&!P
A:create table tab_new like tab_old (使用旧表创建新表) eTi r-7
B:create table tab_new as select col1,col2... from tab_old definition only {p#[.E8
5、说明:删除新表 GR&T
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drop table tabname -UgD
6、说明:增加一个列 pi`sx[T@{Z
Alter table tabname add column col type =+@Ip Xj
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 5\1C@d
7、说明:添加主键: Alter table tabname add primary key(col) B1\@ n$
说明:删除主键: Alter table tabname drop primary key(col) W
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8、说明:创建索引:create [unique] index idxname on tabname(col....) 2x3'm
删除索引:drop index idxname ai/VbV'|
注:索引是不可更改的,想更改必须删除重新建。 GMLDmTV
9、说明:创建视图:create view viewname as select statement Mx&
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删除视图:drop view viewname pC9Ed9uRK
10、说明:几个简单的基本的sql语句 WPbWG$Li
选择:select * from table1 where 范围 nFE0y3GD8
插入:insert into table1(field1,field2) values(value1,value2) L_$M9G|5n
删除:delete from table1 where 范围 aBL+i-
更新:update table1 set field1=value1 where 范围 bqBgq
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ;-Bi~XD
排序:select * from table1 order by field1,field2 [desc] 9D
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总数:select count as totalcount from table1 %\xwu(|kN
求和:select sum(field1) as sumvalue from table1 yj]\%3o<Z7
平均:select avg(field1) as avgvalue from table1 c o}o$}
最大:select max(field1) as maxvalue from table1 4.@gV/U(|
最小:select min(field1) as minvalue from table1 NUiNn 7C
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11、说明:几个高级查询运算词 =l&A9 >\
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A: UNION 运算符 F,B, D^WD
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 S(;3gQ77
B: EXCEPT 运算符 `9%Q2Al
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 j\t"4=,n
C: INTERSECT 运算符 +/idq
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 mRIW9V
注:使用运算词的几个查询结果行必须是一致的。 JvFU7`4@
12、说明:使用外连接 i,G )kt'H
A、left outer join: &W1{o&
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 {.
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;dq AmBG{8
B:right outer join: q#W7.8 Z@
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 =1D* JU
C:full outer join: q*Xp"yBTo
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ;jb+x5t
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二、提升 [&mYW.O<
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) J(&a,w>p
法一:select * into b from a where 1<>1 }^J&D=J5V
法二:select top 0 * into b from a UYu 54`'kg
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) -:txmMT
insert into b(a, b, c) select d,e,f from b; "Q*Z?6[Z
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) L@rKG~{Xy
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 aO@zeKg
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. gd9ZlHo'Id
4、说明:子查询(表名1:a 表名2:b) pH&Q]u;O
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) kTQ`$V(>&
5、说明:显示文章、提交人和最后回复时间 'ad|@Bh
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b h%kB>E~
6、说明:外连接查询(表名1:a 表名2:b) Ugmg,~U~k
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c r>lC(x\B
7、说明:在线视图查询(表名1:a ) ],%}}UN
select * from (SELECT a,b,c FROM a) T where t.a > 1; C 3`2{1
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 64s9Dy@%F
select * from table1 where time between time1 and time2 lyzMKla"
select a,b,c, from table1 where a not between 数值1 and 数值2 GiBq1U-Q
9、说明:in 的使用方法 )i; y4S
select * from table1 where a [not] in ('值1','值2','值4','值6') =dbLA ,z9
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9\W~5J<7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 45`Gv
11、说明:四表联查问题: 7`3he8@ze
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 ..... X~RET[L2
12、说明:日程安排提前五分钟提醒 gM|X":j
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Kb%j;y
13、说明:一条sql 语句搞定数据库分页 YW"?Fy
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 1 sCF
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14、说明:前10条记录 CORNN8=k
select top 10 * form table1 where 范围 !ViHC}:
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.) DvnK_Q!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) f f"Clp
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 zqAK|jbL
(select a from tableA ) except (select a from tableB) except (select a from tableC) ;2RCgX!'%
17、说明:随机取出10条数据 Nzc1)t=
select top 10 * from tablename order by newid() Z2B59,I
18、说明:随机选择记录 (mHFyEG
select newid() 7I4G:-V:^
19、说明:删除重复记录 hIa@JEIt
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ,2?"W8,
20、说明:列出数据库里所有的表名 rS9*_-NH
select name from sysobjects where type='U' M3 8,SH<
21、说明:列出表里的所有的 n15c1=gs
select name from syscolumns where id=object_id('TableName') zx{\SU
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。 Qwx}e\=
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 hB<.u
显示结果: Y VTY{>Q
type vender pcs C<A82u;t%@
电脑 A 1 \@4QG.3&
电脑 A 1 VIbm%b$~
光盘 B 2 F!{N4X>%T
光盘 A 2 *n?6x!A
手机 B 3 ;3'}(_n
手机 C 3 J.":oD
23、说明:初始化表table1 6"
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TRUNCATE TABLE table1 Jg
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24、说明:选择从10到15的记录 yB}y' 5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _*Vq1D ]C
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三、技巧 >FHTBh& Y
1、1=1,1=2的使用,在SQL语句组合时用的较多 c[ff|-<g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ZvNXfC3Ia
如: Uk ?V7?&
if @strWhere !='' oTOe(5N8a
begin ~;m~)D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W5:S+
end _?Jm.nT
else =KT7ZSTV
begin r3Z-mJ$:
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :[(X!eP
end )2F:l0g
我们可以直接写成 hFa\x5I5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @]*z!>1
2、收缩数据库 /]]\jj#^
--重建索引 m{Q{ qJ5>
DBCC REINDEX 6?}8z
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DBCC INDEXDEFRAG R|NmkqTK~(
--收缩数据和日志 Jb $PlOQ
DBCC SHRINKDB r~nrP=-%
DBCC SHRINKFILE $.kIB+K
3、压缩数据库 T:cSv
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dbcc shrinkdatabase(dbname) U$VTk
4、转移数据库给新用户以已存在用户权限 ;?inf`t
exec sp_change_users_login 'update_one','newname','oldname' |c 8p{)
go 1t!Mg{&e[x
5、检查备份集 0; V{yh
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' BY,%+>bc)
6、修复数据库 (U/[i.r5Cj
ALTER DATABASE [dvbbs] SET SINGLE_USER !^q<)!9<EO
GO mMT7`r;l
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -lSm:O@'
GO pSq\3Hp]Q
ALTER DATABASE [dvbbs] SET MULTI_USER `-ENKr]
GO lu-VBVwR
7、日志清除 5bmtUIj
SET NOCOUNT ON @ n;WVG
DECLARE @LogicalFileName sysname, ~n"V0!:'4
@MaxMinutes INT, a3Es7R+S
@NewSize INT shn`>=0.&
USE tablename -- 要操作的数据库名 FG#E?G
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5+%BZ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zCvR/
@NewSize = 1 -- 你想设定的日志文件的大小(M) m/Yi;>I(
-- Setup / initialize 'zT/x`V
DECLARE @OriginalSize int GUat~[lUrj
SELECT @OriginalSize = size |Z 3POD"9
FROM sysfiles 8agd{bxU
WHERE name = @LogicalFileName ^@X
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + N@)4H2_u \
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Hg(\EEe
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' X[;4.imE
FROM sysfiles kV6>O C&^
WHERE name = @LogicalFileName -]'Sy$,A
CREATE TABLE DummyTrans Mm.!$uR
(DummyColumn char (8000) not null) zi*D8!_C
DECLARE @Counter INT, e4CG=K3s
@StartTime DATETIME, %_tL}m{?
@TruncLog VARCHAR(255) e1&c_"TOih
SELECT @StartTime = GETDATE(), 5+3Z?|b
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?wwY8e?S
DBCC SHRINKFILE (@LogicalFileName, @NewSize) fXL>L
EXEC (@TruncLog) k_}ICKzw1
-- Wrap the log if necessary. zO)9(%LS
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired PVEEKKJP]J
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j1d#\
AND (@OriginalSize * 8 /1024) > @NewSize I[t)V*L9
BEGIN -- Outer loop. Vi#(x9.
SELECT @Counter = 0 )sNtwSl^
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3wR5:O$H
BEGIN -- update hDp'=}85@
INSERT DummyTrans VALUES ('Fill Log') N;[w`d'#
DELETE DummyTrans +}9%Duim
SELECT @Counter = @Counter + 1 =:a3cr~
END pm )A*][s
EXEC (@TruncLog) uvA}7L{UO
END 8KoPaq
SELECT 'Final Size of ' + db_name() + ' LOG is ' + KQW
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + c1n? @L
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7CG_UB
FROM sysfiles |Z2_1(
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WHERE name = @LogicalFileName V<nzThM\
DROP TABLE DummyTrans o_G.J4 V
SET NOCOUNT OFF (\R"v^
8、说明:更改某个表 kV<VhBql!
exec sp_changeobjectowner 'tablename','dbo' f$WO{J
9、存储更改全部表 C t SAo\F
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Vl9\&EL
@OldOwner as NVARCHAR(128), PVtQ&m$y
@NewOwner as NVARCHAR(128) .+[[m$J
AS ]m}>/2oSs
DECLARE @Name as NVARCHAR(128) f4w|
DECLARE @Owner as NVARCHAR(128) >Xb]n_`
DECLARE @OwnerName as NVARCHAR(128) * rs_k/2(
DECLARE curObject CURSOR FOR !4z"a@$
select 'Name' = name, Jge;/f!i
'Owner' = user_name(uid) 4L5Wa~5\
from sysobjects 6 'wP?=
where user_name(uid)=@OldOwner m&ZdtB|
order by name *4(.=k
OPEN curObject +;>>c`{
FETCH NEXT FROM curObject INTO @Name, @Owner H9jj**W ;$
WHILE(@@FETCH_STATUS=0) $\P!P.
BEGIN X)uT-F y
if @Owner=@OldOwner :wn![<`3q
begin g" M1HxlV
set @OwnerName = @OldOwner + '.' + rtrim(@Name) sk],_ l<
exec sp_changeobjectowner @OwnerName, @NewOwner C2`END;
end eN jC.w9
-- select @name,@NewOwner,@OldOwner ,g\.C+.S
FETCH NEXT FROM curObject INTO @Name, @Owner ,%ajIs"Gi
END '-v~HwC+/T
close curObject #4"\\
deallocate curObject fk",YtS*
GO 7`WK1_rR\
10、SQL SERVER中直接循环写入数据 IPT}JX'
declare @i int St(7@)gvY
set @i=1 s}HTxY;
while @i<30 zizrc.g/Yg
begin 0q62 {p7
insert into test (userid) values(@i) +5T0]!
set @i=@i+1 6xj&Qo
end >)VrbPRuA
小记存储过程中经常用到的本周,本月,本年函数 2&Efqy8}DZ
Dateadd(wk,datediff(wk,0,getdate()),-1) ?^@;8m
Dateadd(wk,datediff(wk,0,getdate()),6) s'K0C8'U
Dateadd(mm,datediff(mm,0,getdate()),0) +"d{P,[3J
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I.(
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Dateadd(yy,datediff(yy,0,getdate()),0) +$<m ;@mZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) h<uRlTk
上面的SQL代码只是一个时间段 W~7q&||;C
Dateadd(wk,datediff(wk,0,getdate()),-1) u|w[b9^r
Dateadd(wk,datediff(wk,0,getdate()),6) dch(HB}[
就是表示本周时间段. cPtP?)38.
下面的SQL的条件部分,就是查询时间段在本周范围内的: I=lA7}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0,VbB7 z
而在存储过程中 thq(tK7
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %_/_klxnO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?EtK/6dJZt