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。 tk%f_"}
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一、基础 zl@^[km{
1、说明:创建数据库 z%YNZ^d
CREATE DATABASE database-name B$_4ul\)
2、说明:删除数据库 [s>3xWZ+a
drop database dbname ( 2HM"Pd
3、说明:备份sql server 4k;FZo]S
--- 创建 备份数据的 device f8]sjeY
USE master #{8IFA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i)o;,~ee
--- 开始 备份 EL?(D
BACKUP DATABASE pubs TO testBack 'QCIKCn<
4、说明:创建新表 :5NMgR.d
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) / I`TN5~
根据已有的表创建新表: }=^ ,c
A:create table tab_new like tab_old (使用旧表创建新表) r%PWv0z_c
B:create table tab_new as select col1,col2... from tab_old definition only fwFJe(.
5、说明:删除新表 xol%\$|
drop table tabname 6{y7e L3!
6、说明:增加一个列 fCr2'+O"b
Alter table tabname add column col type t1FtYXv`/
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。 e xb}
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7、说明:添加主键: Alter table tabname add primary key(col) 86r"hy~
说明:删除主键: Alter table tabname drop primary key(col) hC<ROD
8、说明:创建索引:create [unique] index idxname on tabname(col....) !DZ=`a?y
删除索引:drop index idxname UX)GA[WI
注:索引是不可更改的,想更改必须删除重新建。 _Je4&KU
9、说明:创建视图:create view viewname as select statement }%_|k^t
删除视图:drop view viewname Zhq_ pus"a
10、说明:几个简单的基本的sql语句 $D^\[^S
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) X.fVbePxUU
删除:delete from table1 where 范围 4XN
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更新:update table1 set field1=value1 where 范围 ^PZ[;F40
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S<i$0p8J;
排序:select * from table1 order by field1,field2 [desc] rOSov"7
总数:select count as totalcount from table1 i HD!v7d7
求和:select sum(field1) as sumvalue from table1 2LwJ%!
平均:select avg(field1) as avgvalue from table1 ]@&X*~c^Z
最大:select max(field1) as maxvalue from table1 DK IH{:L7
最小:select min(field1) as minvalue from table1 F0:]@0>r
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11、说明:几个高级查询运算词 GcVQz[E
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A: UNION 运算符 v"G1vSx)BT
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。 y]j.PT`Cw
B: EXCEPT 运算符 YN8x|DLi?
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。 Mn0.!J
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C: INTERSECT 运算符 2)f_L|o,m
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。 _?c.m*)A
注:使用运算词的几个查询结果行必须是一致的。 VgHO&vU
12、说明:使用外连接 'c35%?]
A、left outer join: Z.\q$U7'9
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。 ;I>nA6A
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 cJ4My#w
B:right outer join: cJo%j -AM
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|SPhaIf
C:full outer join: 7Jn%XxHq
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。 ]Z!Y*v
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二、提升 -b-a21,m>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .zO^"mXjS
法一:select * into b from a where 1<>1 n7!T{+ge
法二:select top 0 * into b from a WPNB!"E98
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) M)bQvjj
insert into b(a, b, c) select d,e,f from b; cgb>Naa<
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) h.\I
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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 Tv ``\<
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !nBbt?*
4、说明:子查询(表名1:a 表名2:b) c!Hz'W
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) Qte5E}V`
5、说明:显示文章、提交人和最后回复时间 z=D5*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6FB0g8
6、说明:外连接查询(表名1:a 表名2:b) KdEvu?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o*KAS@&
7、说明:在线视图查询(表名1:a ) !M~:#k
select * from (SELECT a,b,c FROM a) T where t.a > 1; a~_9BM41T
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 8+'}`
select * from table1 where time between time1 and time2 ;(NTzBq!1
select a,b,c, from table1 where a not between 数值1 and 数值2 Z0<Vss
9、说明:in 的使用方法 ,&o9\|ih7]
select * from table1 where a [not] in ('值1','值2','值4','值6') k1B
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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 !1$x4 qxS
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7<j!qWm0
11、说明:四表联查问题: tia}&9;
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 ..... Ic/hVKYG5
12、说明:日程安排提前五分钟提醒 J}V4.R5d
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 aq?bI:>8
13、说明:一条sql 语句搞定数据库分页 scV%p&{a
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 Jq_\r'YE
14、说明:前10条记录 iJTG+gx
select top 10 * form table1 where 范围 b<u\THy#
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.) eb_.@.a
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .}dLqw
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 7U [C=NL
(select a from tableA ) except (select a from tableB) except (select a from tableC) $[T~<I
17、说明:随机取出10条数据 db )2>
select top 10 * from tablename order by newid() =D(a~8&,
18、说明:随机选择记录 6qZQ20h
select newid() \]x`f3F
19、说明:删除重复记录 3!P^?[p3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 7F"ljkN1S
20、说明:列出数据库里所有的表名 48xgl1R(j
select name from sysobjects where type='U' 7'wpPXdY1
21、说明:列出表里的所有的 MfQ0O?oBp
select name from syscolumns where id=object_id('TableName') c&D+=
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。 G@s:|oe
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 c^|8qvS$
显示结果: Z!v,;MW
type vender pcs @[^ 3yC#
电脑 A 1 eu(Fhs
电脑 A 1 ]5'*^rz ^
光盘 B 2 _c]}m3/
光盘 A 2 =-dnniKW4
手机 B 3 DFr$2Y3H
手机 C 3 Jk.x^
23、说明:初始化表table1 8r(Vz
TRUNCATE TABLE table1 =9&2udV1
24、说明:选择从10到15的记录 1RkN^FZOxq
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Trirb'qO
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三、技巧 R&uPoY,f
1、1=1,1=2的使用,在SQL语句组合时用的较多 7] y3<t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /qQx~doK
如: |6AR!
if @strWhere !='' ic G 9x
begin dOD(<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere zfU Do`V~
end 4W>DW`{
else LsR<r1KDJ
begin 2[w9#6ly
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' {A}T^q!m]
end <(E)M@2
我们可以直接写成 uz8eS'8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere i?_Q@uA~<:
2、收缩数据库 mLq0;uGL|
--重建索引 P~(&lu/;P
DBCC REINDEX :$Cm]RZ
DBCC INDEXDEFRAG !KV!Tkx h
--收缩数据和日志 k2Q[v
DBCC SHRINKDB l"8g9z
DBCC SHRINKFILE (
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3、压缩数据库 1XS~b-St
dbcc shrinkdatabase(dbname) MKtI3vi?
4、转移数据库给新用户以已存在用户权限 $Y/z+ea
exec sp_change_users_login 'update_one','newname','oldname' 2K~v`c*4
go {:cGt2*~^
5、检查备份集 $(&uaDYv
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @#wG)TA
6、修复数据库 HtN:v
ALTER DATABASE [dvbbs] SET SINGLE_USER @Hj]yb5
GO |(~IfSE2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK r%: :q^b3
GO Xp;'Wa"@
ALTER DATABASE [dvbbs] SET MULTI_USER 6~ET@"0uK
GO ,5 ,r.
7、日志清除 2-S}#S}2C
SET NOCOUNT ON #8d#Jw
DECLARE @LogicalFileName sysname, S> Fb'rJ3
@MaxMinutes INT, IlEU6Rs
@NewSize INT [<+T@"y
USE tablename -- 要操作的数据库名 YWPkVvI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 KMT$/I{p,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. uJ"#j
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@NewSize = 1 -- 你想设定的日志文件的大小(M) drCL7.j#L
-- Setup / initialize %~eu&\os
DECLARE @OriginalSize int o5],c9R9b
SELECT @OriginalSize = size ~,W|i
FROM sysfiles tT`S"
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WHERE name = @LogicalFileName 6@Q; LV+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + .WglLUJ:Z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L<
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "P5,p"k:)
FROM sysfiles &IQNsJL!e
WHERE name = @LogicalFileName r0z8?
CREATE TABLE DummyTrans S?DMeZ{:
(DummyColumn char (8000) not null) 89[/UxM)
DECLARE @Counter INT, 8f,",NCgc
@StartTime DATETIME, yJx,4be
@TruncLog VARCHAR(255) )m-(- I
SELECT @StartTime = GETDATE(), Z){fie4WM
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' iLdUus!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) x+sSmW
EXEC (@TruncLog) =j_4!^
-- Wrap the log if necessary. Mf5kknYuL9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^g'uR@uU
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Y}vV.q
AND (@OriginalSize * 8 /1024) > @NewSize `34+~;;Jh
BEGIN -- Outer loop. pJ?y
SELECT @Counter = 0 V\Lh(zPt
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 7WV"Wrl]
BEGIN -- update %i&am=
INSERT DummyTrans VALUES ('Fill Log') MDpx@.A,
DELETE DummyTrans ][f 0ZMa
SELECT @Counter = @Counter + 1 J^kSp
END @$b7
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EXEC (@TruncLog) b#(QZ
END <{V{2V#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _)CCD33$
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 45+kwo0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' MNfc1I_#
FROM sysfiles g6q[
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WHERE name = @LogicalFileName j1JdG<n
DROP TABLE DummyTrans \KEmfCx'n
SET NOCOUNT OFF @
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8、说明:更改某个表 8v)Z/R-
exec sp_changeobjectowner 'tablename','dbo' kaZcYuT.9
9、存储更改全部表 b^Do[o}5
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch DUf. F
@OldOwner as NVARCHAR(128), %z1hXh#+
@NewOwner as NVARCHAR(128) ZA4sEVHW
AS ^]LWcJ?"^!
DECLARE @Name as NVARCHAR(128) CIR2sr0a
DECLARE @Owner as NVARCHAR(128) h#h)=;
DECLARE @OwnerName as NVARCHAR(128) ud(w0eX
DECLARE curObject CURSOR FOR en MHKN g
select 'Name' = name, Zf)<)o*
'Owner' = user_name(uid) >wV2` 6
from sysobjects ++kVq$9@y
where user_name(uid)=@OldOwner gZ(\/m8Z
order by name -OQ6;A"#
OPEN curObject 6.v)q,JL
FETCH NEXT FROM curObject INTO @Name, @Owner e~G IUwJ
WHILE(@@FETCH_STATUS=0) _T^@,!&
BEGIN G!GGT?J
if @Owner=@OldOwner }g.)%Bw!
begin ovtZHq/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) cMUmJH
exec sp_changeobjectowner @OwnerName, @NewOwner P; =,Q$e8
end S?H
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-- select @name,@NewOwner,@OldOwner Yu9(qRK
FETCH NEXT FROM curObject INTO @Name, @Owner e58tf3
END GQkI7C
close curObject ()$tP3o
deallocate curObject w3Qil[rg
GO n\scOM)3
10、SQL SERVER中直接循环写入数据 XQ k,xQ
declare @i int B?XqH_=0L
set @i=1 BfvvJh_
while @i<30 p6{8t}
begin _'r&'s;<z
insert into test (userid) values(@i) O~bzTn
set @i=@i+1 v3/G.B@=
end x8rp Z
小记存储过程中经常用到的本周,本月,本年函数 }!vJ+
Dateadd(wk,datediff(wk,0,getdate()),-1) ,|R\ Z,s
Dateadd(wk,datediff(wk,0,getdate()),6) !uHVg(}
Dateadd(mm,datediff(mm,0,getdate()),0) "qY_O/Eg]]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6[%4Q[
Dateadd(yy,datediff(yy,0,getdate()),0) w#$Q?u ,G
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) vB/G#\Zqz
上面的SQL代码只是一个时间段 9<!Ie^o?
Dateadd(wk,datediff(wk,0,getdate()),-1) )e\IdKl=
Dateadd(wk,datediff(wk,0,getdate()),6) XgZ.UT
就是表示本周时间段. 9&KiG* .
下面的SQL的条件部分,就是查询时间段在本周范围内的: h1N{;SWQ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) SxRa?5
而在存储过程中 ,
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) g"v-hTx
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) k'{Bhi4