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。 O0jOI3/P%
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一、基础 }I
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1、说明:创建数据库 }&/>v' G
CREATE DATABASE database-name nxhlTf>3
2、说明:删除数据库 d@ 8M_
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drop database dbname :AlvWf$d
3、说明:备份sql server !dwZ` D
--- 创建 备份数据的 device nG4ZOx.*1g
USE master mWZP.w^-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'i$._Tx
--- 开始 备份 gk| %
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BACKUP DATABASE pubs TO testBack (/$-2.@
4、说明:创建新表 Y _`JS;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) z4_B/Q
根据已有的表创建新表: ?WXftzdf6u
A:create table tab_new like tab_old (使用旧表创建新表) S||W
B:create table tab_new as select col1,col2... from tab_old definition only EGgw#JAi#t
5、说明:删除新表 D)x^?!
drop table tabname ^k7I+A
6、说明:增加一个列 @4UX~=:686
Alter table tabname add column col type hK)'dG*
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
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7、说明:添加主键: Alter table tabname add primary key(col) L}{3_/t
说明:删除主键: Alter table tabname drop primary key(col) "{vWdY|"
8、说明:创建索引:create [unique] index idxname on tabname(col....) wG MhKZE
删除索引:drop index idxname 7~+Fec`Ut*
注:索引是不可更改的,想更改必须删除重新建。 mvH8hvD9
9、说明:创建视图:create view viewname as select statement ?3K~4-!?/
删除视图:drop view viewname 'V^M+ng
10、说明:几个简单的基本的sql语句 tf 7HhOCYX
选择:select * from table1 where 范围 Gn4b*Y&M]3
插入:insert into table1(field1,field2) values(value1,value2) ?=4oxPe
删除:delete from table1 where 范围 =YVxQj
更新:update table1 set field1=value1 where 范围 !HU$V9C
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! !;8Y?c-D
排序:select * from table1 order by field1,field2 [desc] '8zd]U
总数:select count as totalcount from table1 7+f6?
求和:select sum(field1) as sumvalue from table1 wipl5O@L
平均:select avg(field1) as avgvalue from table1 R.WB.FP
最大:select max(field1) as maxvalue from table1 oS$7k3s
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最小:select min(field1) as minvalue from table1 40MKf/9
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11、说明:几个高级查询运算词 R98YGW_
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A: UNION 运算符 *(5;5r
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。 @!oN]0`F;
B: EXCEPT 运算符 \(
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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。 I,#E`)
C: INTERSECT 运算符 i[9gcL"
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_CqV
注:使用运算词的几个查询结果行必须是一致的。 %T>@Ldt
12、说明:使用外连接 &iw,||#
A、left outer join: mK$E&,OkA
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 `AE6s.p?
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c >;Oa|G
B:right outer join: ij:a+T
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `q]' ^EzJ
C:full outer join: Bj4c_YBte
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 vkJyD/;=
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二、提升 e@VJ-s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |DW^bv
法一:select * into b from a where 1<>1 BMO,eQcB
法二:select top 0 * into b from a XdDQ$'*X
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) SujEF`"
insert into b(a, b, c) select d,e,f from b; VtzZ1/JE
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) &TRKd)w d
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 pD[&,gV$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. |-vyhr0
4、说明:子查询(表名1:a 表名2:b) 'fK=;mM
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) [sG`D-\P[
5、说明:显示文章、提交人和最后回复时间 gYN;Fu-9Z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b XGR63hXND
6、说明:外连接查询(表名1:a 表名2:b) DZL(G [
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c i7T#WfF
7、说明:在线视图查询(表名1:a ) !]s=9(O
select * from (SELECT a,b,c FROM a) T where t.a > 1; <<S4l~"o
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 cd,'37 pZ
select * from table1 where time between time1 and time2 yx`@f8Kr
select a,b,c, from table1 where a not between 数值1 and 数值2 ='D%c^;O8'
9、说明:in 的使用方法 bE%
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select * from table1 where a [not] in ('值1','值2','值4','值6') gNxv.6Pp=
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >CKa?N;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5K9W5hA:D
11、说明:四表联查问题: (9( xJ)
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 ..... SE(<(w
12、说明:日程安排提前五分钟提醒 *IbDA
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Y<POdbg
13、说明:一条sql 语句搞定数据库分页 z5({A2q
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 hoBFC1
14、说明:前10条记录 #]+BIr`
select top 10 * form table1 where 范围 4d@0v n{
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.) M6MxY\uM
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) mQ}\ptdfV
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 Eyf17
(select a from tableA ) except (select a from tableB) except (select a from tableC) 74
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17、说明:随机取出10条数据 0P$19TN
select top 10 * from tablename order by newid() XdIno}pN
18、说明:随机选择记录 8bMw.u=F
select newid() m8L %!6o
19、说明:删除重复记录 \4$Nx/@Q}
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?~.9:93
20、说明:列出数据库里所有的表名 l]DRJ
select name from sysobjects where type='U' oIOeX1$V
21、说明:列出表里的所有的 B> i^ w1
select name from syscolumns where id=object_id('TableName') J%ws-A?6rN
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Hh](n<Bs
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type kKbbsB
显示结果: H4v%$R;K
type vender pcs o+OX^F0
电脑 A 1 *tZ3?X[b
电脑 A 1 |U1u:=[
光盘 B 2 5C*Zb3VG4
光盘 A 2 4V@0L
手机 B 3 !#]kzS0
手机 C 3 vr47PM2al
23、说明:初始化表table1 (.oDxs()I
TRUNCATE TABLE table1 vQXF$/S
24、说明:选择从10到15的记录 myXGMN$i
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *URY8a`bO
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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 Jp)PKS
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, Gg6cjc =dC
如: \K9Y@jnr
if @strWhere !='' coaJDg+
begin 7m8:odeF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $?: -A
end RToX[R;1E
else 0=`aXb-
begin z}5'TV=^
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @AG=Eq9<o
end yF` (GU
我们可以直接写成 P'_ aNU
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?b^<Tny
2、收缩数据库
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--重建索引 )CL/%I,^
DBCC REINDEX cv_O2Q4,@
DBCC INDEXDEFRAG ioTqT:.
--收缩数据和日志 *qMjoP,
DBCC SHRINKDB W#b++}S
DBCC SHRINKFILE mMhe,8E&
3、压缩数据库 OB,T>o@
dbcc shrinkdatabase(dbname) /$vX1T
4、转移数据库给新用户以已存在用户权限 QBoX3w=
exec sp_change_users_login 'update_one','newname','oldname' @J@bD+Q+0
go K1<l/
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5、检查备份集 N/^[c+J[E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' l%2B4d9"v
6、修复数据库 2(D&jL
ALTER DATABASE [dvbbs] SET SINGLE_USER |@-y+vbA*
GO Dhg/>@tw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ; zy;M5l5.
GO _x#r,1V+D
ALTER DATABASE [dvbbs] SET MULTI_USER b[;3y/X
GO +xmZK<{<
7、日志清除 Git2Cet
SET NOCOUNT ON SR)@'-Wd
DECLARE @LogicalFileName sysname, '?fn} V
@MaxMinutes INT, lgAE`Os
@NewSize INT W\DJXM]b
USE tablename -- 要操作的数据库名 &zP\K~Nt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 m}
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. +fIyeX
@NewSize = 1 -- 你想设定的日志文件的大小(M) S
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-- Setup / initialize L?y,xA_
DECLARE @OriginalSize int [7)#3
SELECT @OriginalSize = size wVs |mG"
FROM sysfiles -gS/
WHERE name = @LogicalFileName ]}0+7Q
SELECT 'Original Size of ' + db_name() + ' LOG is ' + / dn]`Ge)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + p:U{3uN 62
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 3^&pb
FROM sysfiles t;ga>^NA"
WHERE name = @LogicalFileName RzSN,bLR
CREATE TABLE DummyTrans p7O4CP>9[
(DummyColumn char (8000) not null) U`'w{~"D%
DECLARE @Counter INT, :(x 90;DW
@StartTime DATETIME, /%N~$ &wW
@TruncLog VARCHAR(255) b}q,cm
SELECT @StartTime = GETDATE(), ]zK} X!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' aR;Q^YJ+a
DBCC SHRINKFILE (@LogicalFileName, @NewSize) L'h'm{i
EXEC (@TruncLog) {la^useg[
-- Wrap the log if necessary. 2I39fZa
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ?Z7C0u#wd
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8c$IsvJg
AND (@OriginalSize * 8 /1024) > @NewSize 54LCoG/
BEGIN -- Outer loop. 9zd)[4%=
SELECT @Counter = 0 (C QgT3V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) IPE(
BEGIN -- update 55N/[{[
INSERT DummyTrans VALUES ('Fill Log') a. 5`Q2
DELETE DummyTrans 3vs2}IV'
SELECT @Counter = @Counter + 1 !*#=7^#
END ;6)|'3.B9
EXEC (@TruncLog) X!_OOfueP8
END Kd,m;S\
SELECT 'Final Size of ' + db_name() + ' LOG is ' + XJOo.Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + -)<Nd:A
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' h;unbz
FROM sysfiles CGg6n CB
WHERE name = @LogicalFileName D{z=)'/F
DROP TABLE DummyTrans $S cjEG:6
SET NOCOUNT OFF d ly 0874
8、说明:更改某个表 Ip1QmP
exec sp_changeobjectowner 'tablename','dbo' ;[zx'e?!
9、存储更改全部表 h/w- &7t
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %r,2ZLZ
@OldOwner as NVARCHAR(128), hQ8{
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@NewOwner as NVARCHAR(128) >\p}UPx
AS KJkcmF}Q
DECLARE @Name as NVARCHAR(128) @',;/j80
DECLARE @Owner as NVARCHAR(128) da^9Fb
DECLARE @OwnerName as NVARCHAR(128) <?nr"V
DECLARE curObject CURSOR FOR /iQ>he~fy
select 'Name' = name, yq,5M1vR
'Owner' = user_name(uid) SO&;]YO
from sysobjects EX5kF
where user_name(uid)=@OldOwner D 7E^;W)H
order by name QY fS-
OPEN curObject !c`1~a!
FETCH NEXT FROM curObject INTO @Name, @Owner jKQP0 t-
WHILE(@@FETCH_STATUS=0) XF$C)id2p
BEGIN nW%c95E
if @Owner=@OldOwner +1623E
begin &]c9}Ic
set @OwnerName = @OldOwner + '.' + rtrim(@Name) dCyQC A[
exec sp_changeobjectowner @OwnerName, @NewOwner wb9zJAsc
end J/*[wj
-- select @name,@NewOwner,@OldOwner nBj7 Q!lW
FETCH NEXT FROM curObject INTO @Name, @Owner ozo8 Tr
END liB>~DVC
close curObject _0`O}
deallocate curObject 5m3sjcp_
GO t2$:*PvE
10、SQL SERVER中直接循环写入数据 3G&1. 8
declare @i int Ywr{/
set @i=1 Te/)[I'Tn
while @i<30 Y+7v~/K=
begin Q'Tn+}B&
insert into test (userid) values(@i) d$Xvax,C
set @i=@i+1 U\z+{]<<
end ?0<3"2Db~
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) =w5w=qB
Dateadd(wk,datediff(wk,0,getdate()),6) rYqvG
Dateadd(mm,datediff(mm,0,getdate()),0) 33C#iR1(WJ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &Gt9a-ne
Dateadd(yy,datediff(yy,0,getdate()),0) BW;u?1Xa
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5f5`7uVJF
上面的SQL代码只是一个时间段 s_8!x
Dateadd(wk,datediff(wk,0,getdate()),-1) Mf63 59
Dateadd(wk,datediff(wk,0,getdate()),6) ),Rj@52l
就是表示本周时间段. &_6:TqJ
下面的SQL的条件部分,就是查询时间段在本周范围内的: f<'C<xnf
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) G7<X l}
而在存储过程中 Tk:y>P!%a
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .PxM
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) "869n37