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。 v[|iuOU
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一、基础 o&AUB`.9~
1、说明:创建数据库 4Ek<
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CREATE DATABASE database-name @!MbPS
2、说明:删除数据库 YG8oy!Zl
drop database dbname zm}1~A
3、说明:备份sql server fBF}-{VX(
--- 创建 备份数据的 device Qpc{7#bp
USE master ]d[q:N]z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2
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--- 开始 备份 NWpRzh8$u
BACKUP DATABASE pubs TO testBack f6"j-IW[z
4、说明:创建新表 [V f|4xcD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~9c9@!RA2
根据已有的表创建新表: q38; w~H
A:create table tab_new like tab_old (使用旧表创建新表) %q Q(@TG
B:create table tab_new as select col1,col2... from tab_old definition only g\.N>P@Bu
5、说明:删除新表 @$*c0.
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drop table tabname lrE0)B5F
6、说明:增加一个列 h>/ViB@"W|
Alter table tabname add column col type !+6l.`2WI
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。 oN$ZZk
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7、说明:添加主键: Alter table tabname add primary key(col) eXd(R>Mx
说明:删除主键: Alter table tabname drop primary key(col) 2ya`2 m
8、说明:创建索引:create [unique] index idxname on tabname(col....) CQ`(,F3(
删除索引:drop index idxname QD<4(@c5|
注:索引是不可更改的,想更改必须删除重新建。 }';&0p2Z
9、说明:创建视图:create view viewname as select statement $!f$R`R^Q\
删除视图:drop view viewname hmH$_YP}
10、说明:几个简单的基本的sql语句 YZ>cE#
选择:select * from table1 where 范围 RFC;1+Jn
插入:insert into table1(field1,field2) values(value1,value2) Wg%-m%7O
删除:delete from table1 where 范围 wl%1B64
更新:update table1 set field1=value1 where 范围 fUL"fMoU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $T4PC5.
排序:select * from table1 order by field1,field2 [desc] -AT@M1K7%
总数:select count as totalcount from table1 Vk (bU=w
求和:select sum(field1) as sumvalue from table1 JdHc'WtS!|
平均:select avg(field1) as avgvalue from table1 ^sKXn:)
最大:select max(field1) as maxvalue from table1 D'h2 DP!
最小:select min(field1) as minvalue from table1 IO#W#wW$M
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11、说明:几个高级查询运算词 t}7wRTG
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A: UNION 运算符 Z|c9%.,
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。 1Tq$ E[
B: EXCEPT 运算符 pqSE|3*l
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。 6dL>Rzl$Dk
C: INTERSECT 运算符 |pqpF?h5|
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。 1l_}O1
注:使用运算词的几个查询结果行必须是一致的。 F47n_JV!d
12、说明:使用外连接 F4x7;?W{*
A、left outer join: ;ZJ,l)BNO
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。 fn OkH
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 lF(!(>YZ
B:right outer join: L{f>;[FR
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。 i =N\[&
C:full outer join: (J&Xo.<Z-
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。 yV/ J(
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二、提升 /8}+#h)[
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) V|\A?
法一:select * into b from a where 1<>1 0 '7s
法二:select top 0 * into b from a zD^f%p ["#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rx>Tc#g
insert into b(a, b, c) select d,e,f from b; Iv72;ZCh?6
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)
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TRLeZ0EC
4、说明:子查询(表名1:a 表名2:b) NP`s[
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) m->%8{L
5、说明:显示文章、提交人和最后回复时间 93IOG{OAY
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9K46>_TyH
6、说明:外连接查询(表名1:a 表名2:b) ~'J =!Xy
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }Tr83B|
7、说明:在线视图查询(表名1:a ) _qt;{,t
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^HFU@/
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 |Xm4(FN\
select * from table1 where time between time1 and time2 `A'I/Hf5
select a,b,c, from table1 where a not between 数值1 and 数值2 R}w wC[{
9、说明:in 的使用方法 Kn#xY3W6
select * from table1 where a [not] in ('值1','值2','值4','值6') tH,K\v`f
10、说明:两张关联表,删除主表中已经在副表中没有的信息 rtL9cw5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) OF<n T
11、说明:四表联查问题: 7 G[ GHc>
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 ..... *OOa)P{^D
12、说明:日程安排提前五分钟提醒 C}=_8N
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 92aDHECo
13、说明:一条sql 语句搞定数据库分页 .;Utkf'I
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 9`CiE
14、说明:前10条记录 +%}5{lu_e
select top 10 * form table1 where 范围 "aWX:WL&}s
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.) >9tkx/J
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #~URLN
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 |:=b9kv
(select a from tableA ) except (select a from tableB) except (select a from tableC) J4Z<Yt/
17、说明:随机取出10条数据 0|s$vqc
select top 10 * from tablename order by newid() !
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18、说明:随机选择记录 '5xuT _
select newid() /ik)4]>
19、说明:删除重复记录 t66f 7AR
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) i[ Gw7'f
20、说明:列出数据库里所有的表名 L\:YbS~]
select name from sysobjects where type='U' GATP
21、说明:列出表里的所有的 fb0T/JTw
select name from syscolumns where id=object_id('TableName') SEQO2`]e:
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。 $: 4mOl
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type p21=$?k!;
显示结果: N
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type vender pcs G{:af:5Fo
电脑 A 1 y13CR2t6
电脑 A 1 1RI #kti-"
光盘 B 2 g~Nij~/
光盘 A 2 XU;{28P
手机 B 3 \}u7T[R=`
手机 C 3 M=\d_O#;Z
23、说明:初始化表table1 c;b[u:>~-
TRUNCATE TABLE table1 xyS2_Q
24、说明:选择从10到15的记录 ,WO%L~db
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2w x[D
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三、技巧 a8bX"#OR&N
1、1=1,1=2的使用,在SQL语句组合时用的较多 =0PNHO\gl
"where 1=1" 是表示选择全部 "where 1=2"全部不选, PUQ_w
如: q*F~~J!P
if @strWhere !='' f\x@ C)E
begin q#Yg0w~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere XDP6T"h
end gfdPx:7^
else ?b*/ddIs
begin ;Xfd1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' M73VeV3DL
end <i{m.pR>
我们可以直接写成 =9DhO7I'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere fR]p+\#8u*
2、收缩数据库 ?8wwd!)x%
--重建索引 3P+4S|@q(4
DBCC REINDEX A=v lC?&Z
DBCC INDEXDEFRAG hkmTpH1<M
--收缩数据和日志 f H#F"^A
DBCC SHRINKDB r/N[7*i
DBCC SHRINKFILE =RW*
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3、压缩数据库 4DQ07w
dbcc shrinkdatabase(dbname) ;S=62_Un
4、转移数据库给新用户以已存在用户权限 l#2r.q^$|
exec sp_change_users_login 'update_one','newname','oldname' vWqyZ-p,q
go
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5、检查备份集
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hb /8Q
6、修复数据库 RlI
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ALTER DATABASE [dvbbs] SET SINGLE_USER Dh\S`nfFq
GO ys&"r":I
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 26\HV
GO M(;y~|e
ALTER DATABASE [dvbbs] SET MULTI_USER [ -9)T
GO bGGeg%7
7、日志清除 W; 3
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SET NOCOUNT ON ]6a/0rg:t
DECLARE @LogicalFileName sysname, {&\J)oZ
@MaxMinutes INT, Ap
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@NewSize INT nu4Pc
USE tablename -- 要操作的数据库名 ]iz_w`I\
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 U=haXx4N
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bjM-Hd/K
@NewSize = 1 -- 你想设定的日志文件的大小(M) ppwd-^f3j
-- Setup / initialize ~u_K&X
DECLARE @OriginalSize int c0!Te'?
SELECT @OriginalSize = size !pd7@FwC
FROM sysfiles g6rv`I$l
WHERE name = @LogicalFileName 5S&aI{;9<
SELECT 'Original Size of ' + db_name() + ' LOG is ' + U-Af7qO
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + uHfhRc9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' M*g2VyZ
FROM sysfiles O]e6i%?
WHERE name = @LogicalFileName )x$!K[=
CREATE TABLE DummyTrans GAg.p?Sq
(DummyColumn char (8000) not null) pu\b`3C(
DECLARE @Counter INT, 20
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@StartTime DATETIME, R19'|TJ
@TruncLog VARCHAR(255) Y
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SELECT @StartTime = GETDATE(), 8pXfT%]
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 9|J8]m?x
DBCC SHRINKFILE (@LogicalFileName, @NewSize) M.o?CX'
EXEC (@TruncLog) D"`%|`O
-- Wrap the log if necessary. UqD5
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1t0bUf;(M
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) w0#%AK
AND (@OriginalSize * 8 /1024) > @NewSize dj?G.-
BEGIN -- Outer loop. bq:wEMM4s
SELECT @Counter = 0 H"2 U)HJl
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 48lzOG
BEGIN -- update y' 2<qj
INSERT DummyTrans VALUES ('Fill Log') =ft9T&ciD
DELETE DummyTrans -Bl/4p
SELECT @Counter = @Counter + 1 Bfbl#ZkyL
END {;U} :Dx
EXEC (@TruncLog) ^%-NPo<
END wG_4$kyj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + J09*v)L
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + C#Y,r)l
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' S*;#'j)4+
FROM sysfiles )8:n}w
WHERE name = @LogicalFileName $B<~0'6}
DROP TABLE DummyTrans y@q1c*|
SET NOCOUNT OFF #g,H("Qy({
8、说明:更改某个表 ty':`)
exec sp_changeobjectowner 'tablename','dbo' N[>:@h
9、存储更改全部表 x]H3Y3
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /#29Y^Z)=
@OldOwner as NVARCHAR(128), 2K
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@NewOwner as NVARCHAR(128) wbBE@RU>!
AS ki#y&{v9Be
DECLARE @Name as NVARCHAR(128) ldP3n:7FS
DECLARE @Owner as NVARCHAR(128) 5Qb;2!
DECLARE @OwnerName as NVARCHAR(128) tzZ|S<e6=\
DECLARE curObject CURSOR FOR yj>){NcX
select 'Name' = name, *8/VSs
'Owner' = user_name(uid) v<j2L"bj
from sysobjects *<w3" iq
where user_name(uid)=@OldOwner ~'(9?81d
order by name dZF8R
OPEN curObject .a {QA
FETCH NEXT FROM curObject INTO @Name, @Owner "=FIFf
WHILE(@@FETCH_STATUS=0) se!g4XEWD
BEGIN T{ok +$w2
if @Owner=@OldOwner 9wzwY[{
begin [@g ~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Vfb<o"BQk
exec sp_changeobjectowner @OwnerName, @NewOwner P7'M],!9w
end Dp^95V@
-- select @name,@NewOwner,@OldOwner W.IH#`-9E
FETCH NEXT FROM curObject INTO @Name, @Owner STw oYn
END :u
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close curObject m.!wsw
deallocate curObject _n7%df
GO r-*l1([eW
10、SQL SERVER中直接循环写入数据 Trpgx
declare @i int f0OgK<.>T
set @i=1 3<+z46`?
while @i<30 f7ZA837Un
begin <W?WUF
insert into test (userid) values(@i) 'bl%Y).9w
set @i=@i+1 %Or2iuO%-,
end 2g0K76=Co:
小记存储过程中经常用到的本周,本月,本年函数 NfOp=X?Y
Dateadd(wk,datediff(wk,0,getdate()),-1) f*v1J<1#
Dateadd(wk,datediff(wk,0,getdate()),6) *G\=i
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Dateadd(mm,datediff(mm,0,getdate()),0) #.o0mguU
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) M= atls
Dateadd(yy,datediff(yy,0,getdate()),0) =88t*dH(,"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .ByU
上面的SQL代码只是一个时间段 (V8?,G >
Dateadd(wk,datediff(wk,0,getdate()),-1) db'K!M)
Dateadd(wk,datediff(wk,0,getdate()),6) ;|;iCaD a+
就是表示本周时间段. 7r['
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~+=E"9Oo
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) \<=IMa0
而在存储过程中 ]r!QmWw~V
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) D@:"f?K>
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *O5: