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。 @wYQLZ
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一、基础 #|{BGVp
1、说明:创建数据库 i_[
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CREATE DATABASE database-name Q8;x9o@p
2、说明:删除数据库
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drop database dbname Ks49$w<
3、说明:备份sql server d$"G1u~%
--- 创建 备份数据的 device jpYw#]Q
USE master f H#F"^A
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <?>I\
--- 开始 备份 ny!lja5[
BACKUP DATABASE pubs TO testBack SQdzEF
4、说明:创建新表 z`86-Ov
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X\b}jo^96
根据已有的表创建新表: a<57(Sf
A:create table tab_new like tab_old (使用旧表创建新表) @MN}^umx`
B:create table tab_new as select col1,col2... from tab_old definition only ;e#>n!<u
5、说明:删除新表 *tTP8ZCQ[
drop table tabname `G"|MM>P
6、说明:增加一个列 (B>yaM#5
Alter table tabname add column col type p~Yy"Ec;p
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。 v{mv*`~nA\
7、说明:添加主键: Alter table tabname add primary key(col) EFa{O`_@U
说明:删除主键: Alter table tabname drop primary key(col) VL_)]LR*)
8、说明:创建索引:create [unique] index idxname on tabname(col....) 4f{[*6 GX
删除索引:drop index idxname k8InbX[
注:索引是不可更改的,想更改必须删除重新建。 2|0Je^$|
9、说明:创建视图:create view viewname as select statement Eonq'Re$
删除视图:drop view viewname %K&+~CJE
10、说明:几个简单的基本的sql语句 %mK3N2N$
选择:select * from table1 where 范围 8~&F/C*
插入:insert into table1(field1,field2) values(value1,value2) l]a^"4L4`o
删除:delete from table1 where 范围 lF;ziF
更新:update table1 set field1=value1 where 范围
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i#L6UKe:Q
排序:select * from table1 order by field1,field2 [desc] _9Dn\=g
总数:select count as totalcount from table1 .x)>f
求和:select sum(field1) as sumvalue from table1
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平均:select avg(field1) as avgvalue from table1 @K,2mhE~h
最大:select max(field1) as maxvalue from table1 pTa'.m
最小:select min(field1) as minvalue from table1 \b_-mnN"
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11、说明:几个高级查询运算词 cwH,l$
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A: UNION 运算符 >%iu!H"
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。 %-@'CNP
B: EXCEPT 运算符 rtB|N-
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。 +l2e[P+qA
C: INTERSECT 运算符 /p"U
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。 g6rv`I$l
注:使用运算词的几个查询结果行必须是一致的。 B8bvp:Ho|
12、说明:使用外连接 iyA*JCD
A、left outer join: 4/*]`
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Ep^B,;~
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Kwy1SyU
B:right outer join: 3q'K5}
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 +O|_P`HBoI
C:full outer join: ]}nu9z<
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 v
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二、提升 r :fwrC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 68vxI|EZ
法二:select top 0 * into b from a Q9`s_4
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 06PhrPVa!\
insert into b(a, b, c) select d,e,f from b; ?,WUJH?^
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) DWF
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ::p-9F
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. iP~sft6
4、说明:子查询(表名1:a 表名2:b) +<)tql*
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Tx y]"_
5、说明:显示文章、提交人和最后回复时间 yQu vW$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `^O'V}T
6、说明:外连接查询(表名1:a 表名2:b) hWe}'L-
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\[L?Rmd
7、说明:在线视图查询(表名1:a ) .(`(chRa}
select * from (SELECT a,b,c FROM a) T where t.a > 1; cj$,ob&DX
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -0A@38, }
select * from table1 where time between time1 and time2 Y Eg
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select a,b,c, from table1 where a not between 数值1 and 数值2 q:xtm?'$
9、说明:in 的使用方法 Vil@?Y"
select * from table1 where a [not] in ('值1','值2','值4','值6') <$"7~i/X
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o:Ln._bj
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RM)1*l`!E
11、说明:四表联查问题:
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... s ;48v
12、说明:日程安排提前五分钟提醒 eA`]KalH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 u=(H#o<#
13、说明:一条sql 语句搞定数据库分页 t@X M /=d
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 3wV86tH%
14、说明:前10条记录 ^it4z gx@
select top 10 * form table1 where 范围 =fY lzZh
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) BfX%|CWh
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0Wa#lkn$I
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 g;$E1U=R-E
(select a from tableA ) except (select a from tableB) except (select a from tableC) HkW/G[7x&
17、说明:随机取出10条数据 lTn;3'
select top 10 * from tablename order by newid() 5fU!'ajaN7
18、说明:随机选择记录 )URwIe{
select newid() wG_4$kyj
19、说明:删除重复记录 (:ZPt(1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ;_x2Ymw
20、说明:列出数据库里所有的表名 C#Y,r)l
select name from sysobjects where type='U' 4DvdEt
21、说明:列出表里的所有的 .8-PB*vb
select name from syscolumns where id=object_id('TableName') )8:n}w
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。 K3Huu!Tr
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 [0K=I64
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显示结果: 7}gA0fP9
type vender pcs !>\9t9
电脑 A 1 ;F|jG}M"
电脑 A 1 x<8\-
光盘 B 2 t9ER;.e
光盘 A 2 >Ja0hS{*
手机 B 3 ggMUdlU
手机 C 3 &Y 'z?N
23、说明:初始化表table1 sc<kiL
TRUNCATE TABLE table1 A8J?A#R*{q
24、说明:选择从10到15的记录 ',DeP>'%>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc o\d |CE;>
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三、技巧 p#)e:/Qy
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,Ak ^nX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Nc,*hsx'
如: fQxSMPWB
if @strWhere !='' tAaYL
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begin *8/VSs
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere e "_&z#
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end X#VEA=4{
else W^w d
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begin 6ezcS}:+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ~'(9?81d
end
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我们可以直接写成 ?%93b ,7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere (WJV.GcP1
2、收缩数据库 n>n"{!
--重建索引 X@cSP7b
DBCC REINDEX ?b5H
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DBCC INDEXDEFRAG eVTO#R*'|
--收缩数据和日志 }&mj.hGv
DBCC SHRINKDB {798=pC<.
DBCC SHRINKFILE rYbCOazr
3、压缩数据库 ;jF%bE3
dbcc shrinkdatabase(dbname) iL+y(]
4、转移数据库给新用户以已存在用户权限 r9<V%PHv
exec sp_change_users_login 'update_one','newname','oldname' fa"\=V2S
go ZH% we
5、检查备份集 Ohc^d"[7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hRk,vB]
6、修复数据库 _<XgC\4O|
ALTER DATABASE [dvbbs] SET SINGLE_USER k/U>N|5
GO B+|IZoR
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2f `&WUe
GO -W9gH
ALTER DATABASE [dvbbs] SET MULTI_USER 9g96 d-
GO ci;&CHa
7、日志清除 -7&?@M,u
SET NOCOUNT ON Ny]lvgu9X
DECLARE @LogicalFileName sysname, r-*l1([eW
@MaxMinutes INT, %S c=_%6
@NewSize INT 1PmX."a
USE tablename -- 要操作的数据库名 k2pT1QZnt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ::ri3Tu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. O6/xPeak
@NewSize = 1 -- 你想设定的日志文件的大小(M) c+H)ed>
-- Setup / initialize wBLsz/
DECLARE @OriginalSize int ZH!;z-R
SELECT @OriginalSize = size sLNNcj(Cy>
FROM sysfiles Y4`QK+~fH
WHERE name = @LogicalFileName V>AS%lXj
SELECT 'Original Size of ' + db_name() + ' LOG is ' + JfSdUWxT
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {b[tA,
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' hw*1g m
FROM sysfiles L -YNz0A
WHERE name = @LogicalFileName {|Bd?U;
CREATE TABLE DummyTrans SijS5irfk
(DummyColumn char (8000) not null) $ND90my
DECLARE @Counter INT,
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@StartTime DATETIME, <;aJ#qT
@TruncLog VARCHAR(255) sx:Hv1d
SELECT @StartTime = GETDATE(), 9]Lo
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4AuH1m)<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) O hi D
EXEC (@TruncLog) +3)[>{~1Z
-- Wrap the log if necessary. x`#22"m
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }{A?PHV5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) fwy"w
AND (@OriginalSize * 8 /1024) > @NewSize *CzCUu:%t
BEGIN -- Outer loop. *{Yh6{
SELECT @Counter = 0 dt<~sOT3s
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) !8o\.uyi
BEGIN -- update my4\mi6P
INSERT DummyTrans VALUES ('Fill Log') QTfu: m{
DELETE DummyTrans )Y~xIj>
SELECT @Counter = @Counter + 1 >J>>\Y(p
END 'd+:D'
EXEC (@TruncLog) Psp^@
END .N!{ U
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6W$rY] h!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [1Uz_HY["3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' i_NJ -K
FROM sysfiles uS&LG#a
WHERE name = @LogicalFileName 0`6),R'x
DROP TABLE DummyTrans rtus`A5p
SET NOCOUNT OFF ![).zi+m
8、说明:更改某个表 +O4( a.
exec sp_changeobjectowner 'tablename','dbo' o _(0
9、存储更改全部表 7pP+5&*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 95[wM6?J
@OldOwner as NVARCHAR(128), bb}?h]a
@NewOwner as NVARCHAR(128) IqNpLh|[
AS rpSr^slr
DECLARE @Name as NVARCHAR(128) l^
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DECLARE @Owner as NVARCHAR(128) m9woredS,
DECLARE @OwnerName as NVARCHAR(128) >gnF]<
DECLARE curObject CURSOR FOR }I]W'<jY
select 'Name' = name, /h7.oD8CU
'Owner' = user_name(uid) P2t_T'R}
from sysobjects E0<)oQ0Xa>
where user_name(uid)=@OldOwner "ee'2O
order by name zA,/@/'(
OPEN curObject aLYLd/ KV
FETCH NEXT FROM curObject INTO @Name, @Owner 'g~@"9'oe
WHILE(@@FETCH_STATUS=0)
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BEGIN o)p[
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if @Owner=@OldOwner gJK KR]4*
begin K?[)E3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) %Lyz_2q A
exec sp_changeobjectowner @OwnerName, @NewOwner 1|]xo3j"'
end dqxd3,Z
-- select @name,@NewOwner,@OldOwner [g`, AmR\!
FETCH NEXT FROM curObject INTO @Name, @Owner 7=vYO|a/4
END W_%W%i|
close curObject Qm; BUG]
deallocate curObject 7OE[RX8!f
GO wA631kr
10、SQL SERVER中直接循环写入数据 VXwPdMy*L
declare @i int ogJ<e_m
set @i=1 nPOO3!<{
while @i<30 3}j1RYtz
begin Za0gs @$
insert into test (userid) values(@i) VGB-h'
set @i=@i+1 VKNp,Lf
end `R0Y+#$8h
小记存储过程中经常用到的本周,本月,本年函数 vtZ?X';wh
Dateadd(wk,datediff(wk,0,getdate()),-1) >D~w}z/fk
Dateadd(wk,datediff(wk,0,getdate()),6) 1AT'S;`
Dateadd(mm,datediff(mm,0,getdate()),0) pqH4w(;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "$DldHC
Dateadd(yy,datediff(yy,0,getdate()),0) k2.G%]j
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <6R"h-u"
上面的SQL代码只是一个时间段 R1/q3x
Dateadd(wk,datediff(wk,0,getdate()),-1) GG+5/hU
Dateadd(wk,datediff(wk,0,getdate()),6) m!:.>y
就是表示本周时间段. -bm,:Iy!
下面的SQL的条件部分,就是查询时间段在本周范围内的: v8~YR'T0`V
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) y?Onb3%
而在存储过程中 4'm q_o#4W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vd(dNu&,<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Zih ?Bm