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。 #1R
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一、基础 =Y[Ae7e
1、说明:创建数据库 LcF3P
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CREATE DATABASE database-name :LG%8Z{R
2、说明:删除数据库 !CKUkoX
drop database dbname h65j,v6B
3、说明:备份sql server U 7?ez
--- 创建 备份数据的 device pXa? Q@6
USE master N3) v,S-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' k*^W
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--- 开始 备份 #w6CL
BACKUP DATABASE pubs TO testBack l[ k$O$jo
4、说明:创建新表 :B~c>:
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) YZ@-0_Z
根据已有的表创建新表: \f#ao<vQm
A:create table tab_new like tab_old (使用旧表创建新表) Ymom 0g+f
B:create table tab_new as select col1,col2... from tab_old definition only _TF>c:m3
5、说明:删除新表 Zlo,#q
drop table tabname ")
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6、说明:增加一个列 Hc9pWr"N
Alter table tabname add column col type EVsZ:Ra^k
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。 9_{!nQC.g
7、说明:添加主键: Alter table tabname add primary key(col) [DwB7l)O(
说明:删除主键: Alter table tabname drop primary key(col) g (k|"g`*
8、说明:创建索引:create [unique] index idxname on tabname(col....) RUKSGj_NJ
删除索引:drop index idxname ^EOjq
注:索引是不可更改的,想更改必须删除重新建。 -&}E:zoe
9、说明:创建视图:create view viewname as select statement 0
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删除视图:drop view viewname Q2Rj0E`
10、说明:几个简单的基本的sql语句 w3D_ c~
选择:select * from table1 where 范围 K-3 _4As
插入:insert into table1(field1,field2) values(value1,value2) $EF@x}h:A
删除:delete from table1 where 范围 d.A0(*k,
更新:update table1 set field1=value1 where 范围 M-Bw9`#Jw
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! TZg7BLfy
排序:select * from table1 order by field1,field2 [desc] _!7o
总数:select count as totalcount from table1 ~l~g0J
求和:select sum(field1) as sumvalue from table1 {,=,0NQKn
平均:select avg(field1) as avgvalue from table1 >^&+,*tsS4
最大:select max(field1) as maxvalue from table1 l.$#IE
最小:select min(field1) as minvalue from table1 T!bu}KO
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11、说明:几个高级查询运算词 "RLb wm~
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A: UNION 运算符 {QID @
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>|2~YxjU
B: EXCEPT 运算符 hh9{md\
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。 #eYVZ=E
C: INTERSECT 运算符 iq$/6!t
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 /eQn$ZRP,
注:使用运算词的几个查询结果行必须是一致的。 V_!i KEU
12、说明:使用外连接 @V)WJ{
A、left outer join: N;Bal/kd2
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。 'Nh^SbD+_|
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 bd4q/w4q
B:right outer join: H^G*5EQK
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。 _q 8m$4
C:full outer join: K@m^QioMj
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 N"TD$NrK\
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二、提升 a0R]hENC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PJ{.jWwD
法一:select * into b from a where 1<>1 _Gu ;U@
法二:select top 0 * into b from a |Bp?"8%*l
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) /!hW6u5
insert into b(a, b, c) select d,e,f from b; rzu^br9X
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) ;QYK {3R?
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 z( wXs&z;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {/ta1&xyG
4、说明:子查询(表名1:a 表名2:b) '' 6
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) ]NCOi?Odx
5、说明:显示文章、提交人和最后回复时间 s6B@:9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ]G:xT v8
6、说明:外连接查询(表名1:a 表名2:b) m|
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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 [C$ 0HW
7、说明:在线视图查询(表名1:a ) #_d%hr~d
select * from (SELECT a,b,c FROM a) T where t.a > 1; <CFur
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 $dR%8@.H
select * from table1 where time between time1 and time2 XebCl{HHp
select a,b,c, from table1 where a not between 数值1 and 数值2 'g#GUSXfj
9、说明:in 的使用方法 {%
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select * from table1 where a [not] in ('值1','值2','值4','值6') < -Nj
10、说明:两张关联表,删除主表中已经在副表中没有的信息 l_:%?4MA
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )7^jq|
11、说明:四表联查问题: KjadX&JD
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... c\Dv3bF
12、说明:日程安排提前五分钟提醒 X_lNnk
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 nB.p}k
13、说明:一条sql 语句搞定数据库分页 ]arP6iN+
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 {#vo^& B
14、说明:前10条记录 SZ_hG D 0
select top 10 * form table1 where 范围 <\5{R@A*6
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) _PIk,!<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) d1-QkW^0y
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 b}fH$.V@
(select a from tableA ) except (select a from tableB) except (select a from tableC) +"!IVHY
17、说明:随机取出10条数据 \4ZQop
select top 10 * from tablename order by newid() wQ5__"D
18、说明:随机选择记录 yC[}gHv
select newid() %9j]N$.V
19、说明:删除重复记录 Nx99dr
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 6
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20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' LE;c+(CAU
21、说明:列出表里的所有的 qVfOf\x.e
select name from syscolumns where id=object_id('TableName') FB@G.f
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 yZ`\.GgC^&
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type /vu7;xVG
显示结果: _xJ&p$&
type vender pcs _/Hu'9432
电脑 A 1 "ggq7cJ}_
电脑 A 1 V|7 cdX#H
光盘 B 2 8L:0Wp
光盘 A 2 (f)QEho7
手机 B 3 ?^dyQhb
手机 C 3 9:1ZL_yf
23、说明:初始化表table1 S7bSR?~L[
TRUNCATE TABLE table1 ;.iy{&$
24、说明:选择从10到15的记录 m*1=-"P
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc R&?p^!`%
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三、技巧 'G&w[8mqY
1、1=1,1=2的使用,在SQL语句组合时用的较多 WDcjj1`l
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !>M: G:K
如: d/MMPge3
if @strWhere !='' 5lT lZRH1
begin PH6uP]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ="V6z$N
end LVSJK.B
else e.[h
begin "h
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8O]$)E
end |q?A8@\u
我们可以直接写成 c5JxKU_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere >B==*,|
2、收缩数据库
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--重建索引 ;*8$BuD
DBCC REINDEX i]P]o)
DBCC INDEXDEFRAG Na4\)({
--收缩数据和日志 =dPrG=A
DBCC SHRINKDB +S$x}b'5q
DBCC SHRINKFILE nk[ixVc
3、压缩数据库 zJPzI{-w|
dbcc shrinkdatabase(dbname) Ta_#Rg*!
4、转移数据库给新用户以已存在用户权限 T!8,R{V]4
exec sp_change_users_login 'update_one','newname','oldname' *cf#:5Nl
go z;T?2~g!
5、检查备份集 Gd!y,n&s
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9BP-Iet
6、修复数据库 -{HA+ YL H
ALTER DATABASE [dvbbs] SET SINGLE_USER [l0>pHl@
GO OmsNo0OA
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK YtFtU;{
GO %
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ALTER DATABASE [dvbbs] SET MULTI_USER &T{+B:*v
GO yJ?6B LJi
7、日志清除 ~x2azY2DP
SET NOCOUNT ON _di[PU=Vh
DECLARE @LogicalFileName sysname, Au9Rr3n
@MaxMinutes INT, aPRF
@NewSize INT BV|LRB}G
USE tablename -- 要操作的数据库名 "lB[IB)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 o]@?QAu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bO9X;}\6
@NewSize = 1 -- 你想设定的日志文件的大小(M) |(]XZ !{
-- Setup / initialize 5~v({R.
DECLARE @OriginalSize int `rvS(p[s
SELECT @OriginalSize = size {q:6;yzxl
FROM sysfiles opd^|xx0
WHERE name = @LogicalFileName ?e0ljx;
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F&^u1RYz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + vLq_l4l
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (<|,LagTuc
FROM sysfiles 3:s!0ty"
WHERE name = @LogicalFileName G22u+ua
CREATE TABLE DummyTrans 'vBuQinn
(DummyColumn char (8000) not null) o^mW`g8[
DECLARE @Counter INT, #>}cuC@
@StartTime DATETIME, t~3!| @3i
@TruncLog VARCHAR(255) af)L+%Q%R
SELECT @StartTime = GETDATE(), .^eajb`:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' EW]rD
DBCC SHRINKFILE (@LogicalFileName, @NewSize) #V@[<S2
EXEC (@TruncLog) 4PR!OB
-- Wrap the log if necessary. n&Bgpt~
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /C}u,dBf
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %AaZc=a[c
AND (@OriginalSize * 8 /1024) > @NewSize fC&hi6
BEGIN -- Outer loop. vkp_v1F%+
SELECT @Counter = 0 :wtK'ld
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) rytves%;C
BEGIN -- update ';Y0qitGB
INSERT DummyTrans VALUES ('Fill Log') xQ%N%
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DELETE DummyTrans =A{F&:+a]
SELECT @Counter = @Counter + 1 )vn{?Ulj
END ;ry~x:7L7
EXEC (@TruncLog) Pd)mLs Jg
END 3VaL%+T$,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3%P<F>6
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {{qu:(_g
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' pC^d-Ii
FROM sysfiles KSz;D+L\
WHERE name = @LogicalFileName 3s;^p,9
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DROP TABLE DummyTrans s+DOr$\
SET NOCOUNT OFF 508v:?^'
8、说明:更改某个表 <- L}N '
exec sp_changeobjectowner 'tablename','dbo' ~wvu7
9、存储更改全部表 6/6M.p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g%TOYZr!X
@OldOwner as NVARCHAR(128), BlnR{Y
@NewOwner as NVARCHAR(128) sFt"2TVr3
AS l|v`B6(
DECLARE @Name as NVARCHAR(128) S"HdjEF7\
DECLARE @Owner as NVARCHAR(128) I'}&s|6
DECLARE @OwnerName as NVARCHAR(128) JVydTvc
DECLARE curObject CURSOR FOR Q`kV|
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select 'Name' = name, IK1'" S|
'Owner' = user_name(uid) H%pD9'q~
from sysobjects 2{|Z?3FJ^
where user_name(uid)=@OldOwner SMonJ;Y
order by name i]9C"Kw$L
OPEN curObject {^8?fJ/L
FETCH NEXT FROM curObject INTO @Name, @Owner w{mw?0
WHILE(@@FETCH_STATUS=0) xu\s2x$
BEGIN w$iQ,--
if @Owner=@OldOwner MroN=%|t
begin xIA] 5@;a
set @OwnerName = @OldOwner + '.' + rtrim(@Name) OYSq)!:
exec sp_changeobjectowner @OwnerName, @NewOwner 'hR0JXy
end GHY+q{'#V_
-- select @name,@NewOwner,@OldOwner ZmI0|r}QbY
FETCH NEXT FROM curObject INTO @Name, @Owner DQ<4`wE M
END nr&bpA/
close curObject zX lcu_rc
deallocate curObject Fs"i fn0
GO ?zex]!R
10、SQL SERVER中直接循环写入数据 9fm9xTL
declare @i int >v2/0>U
set @i=1 D%L^[|)c\s
while @i<30 _ _!LTpp
begin D6-R>"}
insert into test (userid) values(@i) P?p]sLrP
set @i=@i+1 (@->AJF1\
end I3HO><of
小记存储过程中经常用到的本周,本月,本年函数 )pSA|Qt N
Dateadd(wk,datediff(wk,0,getdate()),-1) t W+"/<U
Dateadd(wk,datediff(wk,0,getdate()),6) $GP66Ev
Dateadd(mm,datediff(mm,0,getdate()),0) 60;_^v
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) eSQkW
Dateadd(yy,datediff(yy,0,getdate()),0) ^hXm=r4ozR
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) KRz~3yH{c
上面的SQL代码只是一个时间段 wx^Det
Dateadd(wk,datediff(wk,0,getdate()),-1) hC[=e`j
Dateadd(wk,datediff(wk,0,getdate()),6) kDol 1v`
就是表示本周时间段.
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下面的SQL的条件部分,就是查询时间段在本周范围内的: 9U8x&Z]P
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )(0if0D4
而在存储过程中 `Fie'[F5,)
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `JO>g=,4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) tn#cVB3