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。 m:B9~lbT+
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一、基础 (rqc_ZU5
1、说明:创建数据库
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CREATE DATABASE database-name 'L?e)u.
2、说明:删除数据库 x1H1[0w,i
drop database dbname x1]J
3、说明:备份sql server eyW8?:
--- 创建 备份数据的 device &H8wYs
USE master B-^r0/y;
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' kvcDa+#
--- 开始 备份 Em)U`"j/9
BACKUP DATABASE pubs TO testBack "| Oj!&0
4、说明:创建新表 pHQrjEF*
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) LNp{lC
根据已有的表创建新表: g)$/'RB
A:create table tab_new like tab_old (使用旧表创建新表) \]C_ul'
B:create table tab_new as select col1,col2... from tab_old definition only -Zq\x'
5、说明:删除新表 -yOwX2Wv5;
drop table tabname z^lcc7
6、说明:增加一个列 bGw56s'R5~
Alter table tabname add column col type )X
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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。 RO+ jVY~H-
7、说明:添加主键: Alter table tabname add primary key(col) !LI6_Oq
说明:删除主键: Alter table tabname drop primary key(col) YP
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8、说明:创建索引:create [unique] index idxname on tabname(col....) fi%)520
删除索引:drop index idxname &1/OwTI4J
注:索引是不可更改的,想更改必须删除重新建。 WC0z'N({W
9、说明:创建视图:create view viewname as select statement `%QXaKO-
删除视图:drop view viewname M~%P1@%
10、说明:几个简单的基本的sql语句 Hjhgu=
选择:select * from table1 where 范围 &~mJ
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插入:insert into table1(field1,field2) values(value1,value2) '8J!(+
删除:delete from table1 where 范围 H9;0$Y(e-
更新:update table1 set field1=value1 where 范围 ;~D$rT
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yFoPCA86y
排序:select * from table1 order by field1,field2 [desc] Hlhd6be
总数:select count as totalcount from table1 }NjZfBQW`
求和:select sum(field1) as sumvalue from table1 IiU\}<O
平均:select avg(field1) as avgvalue from table1 EfX\" y
最大:select max(field1) as maxvalue from table1 e!W U
最小:select min(field1) as minvalue from table1 :HW| mqKd
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11、说明:几个高级查询运算词 >$$z 6A[
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A: UNION 运算符 "; 1@f"kw
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。 P ~ :
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B: EXCEPT 运算符 g(_xo\
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。 5P Zzaz<
C: INTERSECT 运算符 _(zZrUHB
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。 hrNB"W|?x
注:使用运算词的几个查询结果行必须是一致的。 GYZP?E p*
12、说明:使用外连接 rp9?p%
A、left outer join: {N3&JL5\"E
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。 g.Tc>?~
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 (Bq^
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B:right outer join: TAxu ]C$P
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。 3Fb9\2<H
C:full outer join: (>
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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。 ho-#Xbq#g
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二、提升 [rkw k\m*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) lihIPMU
法一:select * into b from a where 1<>1 @)\4 $#+-
法二:select top 0 * into b from a
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 80zpRU"
insert into b(a, b, c) select d,e,f from b; #x qiGK
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ]_BH"ng}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Q,K$)bM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. }?\^^v h7
4、说明:子查询(表名1:a 表名2:b) 8.,d`~
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) P_4E<"eK
5、说明:显示文章、提交人和最后回复时间 @Jx1n Q^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b IRGcE&m
6、说明:外连接查询(表名1:a 表名2:b) h ;@c%Vm
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c qnCjNN
7、说明:在线视图查询(表名1:a ) WBD?|Ss
select * from (SELECT a,b,c FROM a) T where t.a > 1; He,,bq
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 @R-11wP)M
select * from table1 where time between time1 and time2 T>f6V 5
select a,b,c, from table1 where a not between 数值1 and 数值2 Ol B9z
9、说明:in 的使用方法 dz?On\66
select * from table1 where a [not] in ('值1','值2','值4','值6') z&cM8w:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7Db}bDU1
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Jd^Lnp6?
11、说明:四表联查问题: c/Fgx/hr
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 ..... lJ]]FuA-Q
12、说明:日程安排提前五分钟提醒 zYrJHn#vB
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 nY7gST
13、说明:一条sql 语句搞定数据库分页 &wAVO_s
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 m]vS"AdX
14、说明:前10条记录 X% )~i[_DV
select top 10 * form table1 where 范围 hq&|
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.) @DIEENiM
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #dKy{Q3he
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 &|j0GP&
(select a from tableA ) except (select a from tableB) except (select a from tableC) CT5s`v!s
17、说明:随机取出10条数据 N>Ih2>8t
select top 10 * from tablename order by newid() W]oa7VAq
18、说明:随机选择记录 76bMy4re
select newid() hxzA1s%~
19、说明:删除重复记录 CuD}Uo+u
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) m.p$f$A_
20、说明:列出数据库里所有的表名 C6EGM/m8
select name from sysobjects where type='U' C{,^4Eh3r
21、说明:列出表里的所有的 9dw*
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select name from syscolumns where id=object_id('TableName') KF6C=,Yc%
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。 _1Q6FI5iR
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 =&6sU{j*
显示结果: .%y'q!?
type vender pcs ; >>n#8`
电脑 A 1 Th$Z9+()
电脑 A 1 @R}3f6@67
光盘 B 2 9/!1J
光盘 A 2 <#J5.I 1
手机 B 3 OLPY<ax
手机 C 3 $[}EV(#y
23、说明:初始化表table1 F~i ~%f,
TRUNCATE TABLE table1 S2DG=hi`GK
24、说明:选择从10到15的记录 67hfv e
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc gROK4'j6y
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三、技巧 ywl=@
1、1=1,1=2的使用,在SQL语句组合时用的较多 #bBh. ^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, UOsK(mB
如: }NoP(&ebz*
if @strWhere !='' R)BXN~dQ
begin .b+ix=:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere SkMFJ?J/
end 4w~%MZA^
else p J_+n:_{
begin E_En"r)y
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' gs;^SRE I
end
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我们可以直接写成 $,2T~1tE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PcEE`.
2、收缩数据库 Yb-{+H8{J
--重建索引 mE`qA*=?
DBCC REINDEX SOq:!Qt
DBCC INDEXDEFRAG b~}$Ch3ymW
--收缩数据和日志 |4g0@}nr+W
DBCC SHRINKDB $:%E<j4Dn
DBCC SHRINKFILE ;xe.0j0h
3、压缩数据库 BO#tn{(#
dbcc shrinkdatabase(dbname) yw$4Hlj5
4、转移数据库给新用户以已存在用户权限 n8F~!|lQ0
exec sp_change_users_login 'update_one','newname','oldname' k'PvTWR
go Lj(cCtb)
5、检查备份集 |mE;HvQF
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?"r=08
6、修复数据库 3r,~-6
ALTER DATABASE [dvbbs] SET SINGLE_USER 'St6a*
GO )PTvw>
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZaU8eg7
GO ^t5My[R
ALTER DATABASE [dvbbs] SET MULTI_USER >9rZVNMU
GO IC&P-X_aP
7、日志清除 ^e_LnJ+
SET NOCOUNT ON chKK9SC+|
DECLARE @LogicalFileName sysname, n'v\2(&uYN
@MaxMinutes INT, -z~!%4 a
@NewSize INT Ac|\~w[\
USE tablename -- 要操作的数据库名 iW^J>aKy
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 dgF%&*Il]O
@MaxMinutes = 10, -- Limit on time allowed to wrap log. S@qR~_>a
@NewSize = 1 -- 你想设定的日志文件的大小(M) E I zy
-- Setup / initialize .dk<?BI#H
DECLARE @OriginalSize int 7Vsp<s9bj
SELECT @OriginalSize = size A$3Rbn}"
FROM sysfiles IO)#O<
WHERE name = @LogicalFileName m9oOH5@K~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + a3<:F2=~\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @2/|rq
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' OIL8'xY.w
FROM sysfiles NDP"
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WHERE name = @LogicalFileName [p9v#\G; [
CREATE TABLE DummyTrans dv>n38&mDQ
(DummyColumn char (8000) not null) ?:J_+?{E
DECLARE @Counter INT, H#_Zv]
@StartTime DATETIME, Z;Hkx1
@TruncLog VARCHAR(255) M/quswn1
SELECT @StartTime = GETDATE(), ,< x/
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *u1q7JFQk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Si>38vCJ*
EXEC (@TruncLog) VFL^-tXnA^
-- Wrap the log if necessary. "vSKj/]
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired NC%hsg^0/
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 4}h}`KZZ
AND (@OriginalSize * 8 /1024) > @NewSize yl~_~<s6
BEGIN -- Outer loop. ^~;ia7V&2
SELECT @Counter = 0 "0PrdZMx
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) W~'xJ
BEGIN -- update )"pvF8JR%3
INSERT DummyTrans VALUES ('Fill Log') R~4X?@ZB
DELETE DummyTrans n(J>'Z
SELECT @Counter = @Counter + 1 RyJy%|\-S
END xKG7d8=
EXEC (@TruncLog) );h(D!D,
END ^obuMQ;
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9p qsr~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Bi:lC5d5?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' din,yHu~
FROM sysfiles Bzrnmz5S
WHERE name = @LogicalFileName 3T)rJEN A
DROP TABLE DummyTrans }yEV&&
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SET NOCOUNT OFF w'2FYe{wj
8、说明:更改某个表 RJ{$`d
exec sp_changeobjectowner 'tablename','dbo' ixu*@{<Z(
9、存储更改全部表 y|}~"^+T
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $]We |
@OldOwner as NVARCHAR(128), #m.e9MU
@NewOwner as NVARCHAR(128) ^
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AS F'Y ad
DECLARE @Name as NVARCHAR(128) cRVL1ne
DECLARE @Owner as NVARCHAR(128) . ,^WCyvq
DECLARE @OwnerName as NVARCHAR(128) 2|,L 9
DECLARE curObject CURSOR FOR I_ mus<sE
select 'Name' = name, IC0L&;En
'Owner' = user_name(uid) dT|f<E/P
from sysobjects CaJ-oy8
where user_name(uid)=@OldOwner P35DVK S
order by name Dcvul4Q
OPEN curObject \b"rf697,
FETCH NEXT FROM curObject INTO @Name, @Owner E$)| Kv^
WHILE(@@FETCH_STATUS=0) WR)=VE
BEGIN ^)Hf%
if @Owner=@OldOwner Plp.\N%f3
begin R@\}iyM
set @OwnerName = @OldOwner + '.' + rtrim(@Name) l(?B0
exec sp_changeobjectowner @OwnerName, @NewOwner etr-\Cp
end b#
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-- select @name,@NewOwner,@OldOwner jmID@37t
FETCH NEXT FROM curObject INTO @Name, @Owner X_TjJmc
END 0SIC=p=J
close curObject ETdXk&AN
deallocate curObject dH^6K0J
GO by@KdQow
10、SQL SERVER中直接循环写入数据 ST*h{:u&A
declare @i int K3?5bT_{
set @i=1 Y<xqws
while @i<30 S/'0czDMW
begin a;HAuy`M x
insert into test (userid) values(@i) E5&Z={
set @i=@i+1 DXiA4ihr=
end =Z^5'h~
小记存储过程中经常用到的本周,本月,本年函数 %#x4wi
Dateadd(wk,datediff(wk,0,getdate()),-1) /MF
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Dateadd(wk,datediff(wk,0,getdate()),6) UCLM*`M
Dateadd(mm,datediff(mm,0,getdate()),0) ^c\O,*:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) JI"/,fK^
Dateadd(yy,datediff(yy,0,getdate()),0) j<t3bM-G
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Qg*\aa94
上面的SQL代码只是一个时间段 }iUK`e
Dateadd(wk,datediff(wk,0,getdate()),-1) i HD!v7d7
Dateadd(wk,datediff(wk,0,getdate()),6) ^[?y 2A:
就是表示本周时间段. c{MoeIG)v@
下面的SQL的条件部分,就是查询时间段在本周范围内的: <7^|@L
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) D\Ak-$kJ^
而在存储过程中 \=ML*Gi*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) b>07t!;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) u"v7shRp: