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。 0A75)T=lQ
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一、基础 O<?.iF%
1、说明:创建数据库 7VfPS5se
CREATE DATABASE database-name U\"FYTC
2、说明:删除数据库 v dU)
drop database dbname ofCN[u
3、说明:备份sql server pE G!j ~
--- 创建 备份数据的 device _J_QB]t
USE master L^ U.h
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' W)odaab7
--- 开始 备份 u&o<>d;)
BACKUP DATABASE pubs TO testBack 4tp}
4、说明:创建新表 [](] "r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) C'joJEo
根据已有的表创建新表: O F?o
A:create table tab_new like tab_old (使用旧表创建新表) ^`9O$.'@
B:create table tab_new as select col1,col2... from tab_old definition only . H8 6f !=
5、说明:删除新表 a#/~rNRY
drop table tabname 6lQP+! EF
6、说明:增加一个列 RJD(c#r$
Alter table tabname add column col type {_jbFJ
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。 mk3,ke8
7、说明:添加主键: Alter table tabname add primary key(col) 7)x788Z6
说明:删除主键: Alter table tabname drop primary key(col) ,GF(pCZzG
8、说明:创建索引:create [unique] index idxname on tabname(col....) uNvdlY]
删除索引:drop index idxname 6J3<k(#:
注:索引是不可更改的,想更改必须删除重新建。 'u:J
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9、说明:创建视图:create view viewname as select statement 8+&Da
删除视图:drop view viewname D[K!xq
10、说明:几个简单的基本的sql语句 edfb7prfTl
选择:select * from table1 where 范围 mfgUf
插入:insert into table1(field1,field2) values(value1,value2) lnrs4s Km
删除:delete from table1 where 范围 =n_>7@9l
更新:update table1 set field1=value1 where 范围 &^F'ME
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! z3|5E#m
排序:select * from table1 order by field1,field2 [desc] *7yrm&@nG
总数:select count as totalcount from table1 SA,+oq(
求和:select sum(field1) as sumvalue from table1 ded:yho
平均:select avg(field1) as avgvalue from table1 )p
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最大:select max(field1) as maxvalue from table1 ]l=iKl
最小:select min(field1) as minvalue from table1 F%:o6mT
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11、说明:几个高级查询运算词 ,+'VQa"]
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A: UNION 运算符 +)*oPSQ5
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。 o?wEX%
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。 T$o;PJc
C: INTERSECT 运算符 /9
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 s[u*~A
注:使用运算词的几个查询结果行必须是一致的。 U%aDkC+M
12、说明:使用外连接 RnUud\T/
A、left outer join: hJ*#t<.<P;
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 >d^DN;p
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c dPF*G$
B:right outer join: .2*h!d)E
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。 6'1Lu1w
C:full outer join: ^J&}C
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。 Ev1gzHd!i
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二、提升 )C0 y<:</
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) M HKnHPv
法一:select * into b from a where 1<>1 wl%I(Cw{]
法二:select top 0 * into b from a 3q0S}<h al
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #i-b|J+%
insert into b(a, b, c) select d,e,f from b; U{8x.CJ]
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) 7m;<b$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )xYGJq4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0
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4、说明:子查询(表名1:a 表名2:b) W,[iRmxn
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) qE{L42
5、说明:显示文章、提交人和最后回复时间 ;b0;66C8|
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )bK3%>H#
6、说明:外连接查询(表名1:a 表名2:b) }ykc
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Y?JB%%WWI
7、说明:在线视图查询(表名1:a ) ST[E$XL6
select * from (SELECT a,b,c FROM a) T where t.a > 1; ?2Sm
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 kntULI$`
select * from table1 where time between time1 and time2 %[k"A
select a,b,c, from table1 where a not between 数值1 and 数值2 JYa3xeC;
9、说明:in 的使用方法 jUrUM.CJ\N
select * from table1 where a [not] in ('值1','值2','值4','值6') p1
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 !~ZAm3GwL
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 3U[:N
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11、说明:四表联查问题: 7G
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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 ..... UkM#uKr:
12、说明:日程安排提前五分钟提醒 r.v.y[u
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;~Q`TWC
13、说明:一条sql 语句搞定数据库分页 >ToI$~84
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 Lv:;}
14、说明:前10条记录 9]^NAlno
select top 10 * form table1 where 范围 a- 7RJ.
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.) NsL!AAN[V
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) dp*E#XCr1
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 6MelN^\[7
(select a from tableA ) except (select a from tableB) except (select a from tableC) Q`z2SYz>
17、说明:随机取出10条数据 C$`^(?iO/
select top 10 * from tablename order by newid() NdM \RD_R
18、说明:随机选择记录 w9CX5Fg
select newid() xgZ<.r
19、说明:删除重复记录 )Xice=x9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) OA&r8WK3
20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' !.w|+-JKO
21、说明:列出表里的所有的 G%SoC
select name from syscolumns where id=object_id('TableName') Ft?Yc 5
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 t9&=; s
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type m%)S<L7
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显示结果: p+^K$w^Cs
type vender pcs (%*~5%l\
电脑 A 1 Ny]]L
电脑 A 1 FOS*X
光盘 B 2 /7K7o8g
光盘 A 2 *xDV8iu_
手机 B 3 G Cp90
手机 C 3 d"}lh:L9
23、说明:初始化表table1 v'SqH,=d
TRUNCATE TABLE table1 Cuo"6, M
24、说明:选择从10到15的记录 a#+;BH1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #[y2nK3zF
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三、技巧 8FgF6ip
1、1=1,1=2的使用,在SQL语句组合时用的较多 r
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, )4jS}
如: @Qd5a(5W M
if @strWhere !='' :<xf'.
begin H=*2A!O[_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >*]B4Q
end ,-1d2y
else &IkHP/
begin .Iv`B:4
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' __)"-\w-_(
end ,~XAV ;+
我们可以直接写成 G+K`FUNA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere -8&P1jrI
2、收缩数据库 .zvvk
--重建索引 J&;' gT
DBCC REINDEX *N%)+-
DBCC INDEXDEFRAG 2Kw i4R
--收缩数据和日志 E=qfI>2U&
DBCC SHRINKDB /!W',9ua6
DBCC SHRINKFILE %TzdpQp"
3、压缩数据库 phy:G}F6%
dbcc shrinkdatabase(dbname) )9kp[hY
4、转移数据库给新用户以已存在用户权限 cxnEcX\
exec sp_change_users_login 'update_one','newname','oldname' &8hW~G>(m
go HUx-8<ws
5、检查备份集 L%/atl!
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ky[ ^uQ>0
6、修复数据库 &[$t%:`
ALTER DATABASE [dvbbs] SET SINGLE_USER 0B(Y{*QB
GO CZ,2Rq
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @gm!D`YL
GO zO 6Sl[)
ALTER DATABASE [dvbbs] SET MULTI_USER Bx0=D:j
GO _>G=xKA#e
7、日志清除 2.&%mSN
SET NOCOUNT ON Uk4G9}I
DECLARE @LogicalFileName sysname, x6
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@MaxMinutes INT, Sh 7ob2
@NewSize INT S,RC;D7
USE tablename -- 要操作的数据库名 R5fZ}C7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 sb</-']a
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 3s_$.
@NewSize = 1 -- 你想设定的日志文件的大小(M) |7b@w;q,D
-- Setup / initialize
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DECLARE @OriginalSize int y@dTdR2Wc
SELECT @OriginalSize = size 9+:<RFJ
FROM sysfiles M|qJZ#{4>
WHERE name = @LogicalFileName {\ogw0X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + >C}KSyV;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + zq]:.s
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' d>x(Bj6
FROM sysfiles @|@6pXR.
WHERE name = @LogicalFileName BU=Ta$#BZ
CREATE TABLE DummyTrans u$+nl~p[&
(DummyColumn char (8000) not null) NzbHg p
DECLARE @Counter INT, ?wMS[Kj
@StartTime DATETIME, )7a
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@TruncLog VARCHAR(255) zO3}c3D~q
SELECT @StartTime = GETDATE(), "Fqrk>Q~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' G_6!w//
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 42wZy|oqp
EXEC (@TruncLog) H2E'i\
-- Wrap the log if necessary. -<^3!C >
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w/Wd^+IIn
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) `+GiSj8'G
AND (@OriginalSize * 8 /1024) > @NewSize +=(@=PJ6
BEGIN -- Outer loop. }*56DX
SELECT @Counter = 0 -FQS5Zb.!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) poXT)2^)
BEGIN -- update MMf_
INSERT DummyTrans VALUES ('Fill Log') ilFS9A3P
DELETE DummyTrans tj[-|h
SELECT @Counter = @Counter + 1 P^'}3*8S
END !6`&0eY
EXEC (@TruncLog) N-}|!pqb
END Q=#!wWVP
SELECT 'Final Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + cDh\$7'b
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J24H}^~na
FROM sysfiles H:X(><J
WHERE name = @LogicalFileName e)]DFP[n
DROP TABLE DummyTrans /UiB1-*b
SET NOCOUNT OFF /4,U@s)"/
8、说明:更改某个表 n$ZxN"q <
exec sp_changeobjectowner 'tablename','dbo' Xh`Oin}<
9、存储更改全部表 RzqU`<//
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 6('xIE(R
@OldOwner as NVARCHAR(128), l7uEUMV
@NewOwner as NVARCHAR(128) ;`FR1KIg
AS n$3w=9EX*
DECLARE @Name as NVARCHAR(128)
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DECLARE @Owner as NVARCHAR(128) B[[1=
DECLARE @OwnerName as NVARCHAR(128) !tuK.?q|l
DECLARE curObject CURSOR FOR ~{!,ZnO*
select 'Name' = name, j4Y] 8
'Owner' = user_name(uid) zWf(zxGAz
from sysobjects 9v76A~~
where user_name(uid)=@OldOwner -A1:S'aN-
order by name o.>Yj)U
OPEN curObject lsB.>N lU
FETCH NEXT FROM curObject INTO @Name, @Owner k:CSH{ s5{
WHILE(@@FETCH_STATUS=0) *|)O
BEGIN 'd9cCQ}
if @Owner=@OldOwner FO?I}G22
begin <u2iXH5w
set @OwnerName = @OldOwner + '.' + rtrim(@Name) "Kf4v|6;
exec sp_changeobjectowner @OwnerName, @NewOwner 5z9'~Gfb
end txy'7t
-- select @name,@NewOwner,@OldOwner _OR[RGy
FETCH NEXT FROM curObject INTO @Name, @Owner #L xfE<^
END $
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close curObject a`S3v
deallocate curObject r }Nq"s<
GO wI2fCq(a0
10、SQL SERVER中直接循环写入数据 mp17d$R-
declare @i int 3H,>[&d
set @i=1 n|!O .+\b
while @i<30 No(S#,vJ;
begin fh@/fd
insert into test (userid) values(@i) u&$1XZ!es
set @i=@i+1 B \>W
end G>W:3y
小记存储过程中经常用到的本周,本月,本年函数 Q?-u J1J
Dateadd(wk,datediff(wk,0,getdate()),-1) |~YhN'OJ
Dateadd(wk,datediff(wk,0,getdate()),6) 6G>bZ+
Dateadd(mm,datediff(mm,0,getdate()),0) Tg6nb7@P
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) dsA::jR0P6
Dateadd(yy,datediff(yy,0,getdate()),0) @wW)#!Mou
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2T}FX4'
上面的SQL代码只是一个时间段 *mfPq"/
Dateadd(wk,datediff(wk,0,getdate()),-1) Aq{7WA
Dateadd(wk,datediff(wk,0,getdate()),6) a: [m;
就是表示本周时间段. UJGmaE
下面的SQL的条件部分,就是查询时间段在本周范围内的: a8r+G]Z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) StM)lVeF
而在存储过程中
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) DP4l
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0/?=FM>