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。 W3GNA""O
LHkQ'O0
=^tA_AxVw
一、基础 iX "C/L|JN
1、说明:创建数据库
s2REt$.q
CREATE DATABASE database-name 6KRO{QK
2、说明:删除数据库 Yf}xwpuLk
drop database dbname *z8|P#@
3、说明:备份sql server 0^3+P%(o@
--- 创建 备份数据的 device D=+NxR[
USE master ,eRQu.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' TB!(('
--- 开始 备份 T^:fn-S}=
BACKUP DATABASE pubs TO testBack 4CrLkr
4、说明:创建新表 p*20-!{A
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sOpep
根据已有的表创建新表: <%P2qgz5
A:create table tab_new like tab_old (使用旧表创建新表) D+RiM~LH8
B:create table tab_new as select col1,col2... from tab_old definition only xr%#dVk
5、说明:删除新表 h&;t.Gdf
drop table tabname nB5zNyY4
6、说明:增加一个列 S6g<M5^R
Alter table tabname add column col type }ptq
)p
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 a`!@+6yC
7、说明:添加主键: Alter table tabname add primary key(col) t e,[f
说明:删除主键: Alter table tabname drop primary key(col) Y`BRh9Sa
8、说明:创建索引:create [unique] index idxname on tabname(col....) }t%W1UJ
删除索引:drop index idxname z~{&}Em ~
注:索引是不可更改的,想更改必须删除重新建。 ypdT&5Mqb!
9、说明:创建视图:create view viewname as select statement m@Rtlb
删除视图:drop view viewname Ba'LRz
10、说明:几个简单的基本的sql语句 Bd~1P/
选择:select * from table1 where 范围 )Xtnk
插入:insert into table1(field1,field2) values(value1,value2) -7{$Vj
删除:delete from table1 where 范围 UbamB+QT
更新:update table1 set field1=value1 where 范围 u0Nm.--;_3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 5Qh?>n>*
排序:select * from table1 order by field1,field2 [desc] }`\/f
总数:select count as totalcount from table1 eOI (6U!
求和:select sum(field1) as sumvalue from table1 `5~3G2T
平均:select avg(field1) as avgvalue from table1
rsXq- Pq*
最大:select max(field1) as maxvalue from table1 6"f}O<M5H
最小:select min(field1) as minvalue from table1 5d\q-d
!?!C'-ps
5ZY<JA3
ye}p~&
11、说明:几个高级查询运算词 >e,mg8u6$
$I9qgDJ)
0#*Lw }qi
A: UNION 运算符 c>"cX&
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。 UVQ7L9%?f
B: EXCEPT 运算符 '#/G,%m<!i
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。 kgi>}
%
C: INTERSECT 运算符 [U/(<?F{(
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。 ._O
注:使用运算词的几个查询结果行必须是一致的。 ACq7dLys,B
12、说明:使用外连接 w= P9FxB
A、left outer join: L+}n@B
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。 Iw<i@=V
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 {0"YOS`3AX
B:right outer join: *%/~mSx
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。 ^-z=`>SrS"
C:full outer join: A:l@_*C..
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。 H<EQu|f&x
k%]=!5F
P
[Uy
二、提升 ?>"Yr,b?
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) jhbonuV_
法一:select * into b from a where 1<>1 A][fLlpr
法二:select top 0 * into b from a Vv1|51B
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Y5ZZ3Ati
insert into b(a, b, c) select d,e,f from b; M-V&X&?j
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) -#!x|ne
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /,=@8k!t?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
-!W<DJ*
4、说明:子查询(表名1:a 表名2:b) 9}a_:hAy/
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) 3I\n_V<
5、说明:显示文章、提交人和最后回复时间 7\FXz'hA
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V-'K6mn;
6、说明:外连接查询(表名1:a 表名2:b) G)v
#+4
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W6 H,6v
7、说明:在线视图查询(表名1:a ) l<0}l^C.
select * from (SELECT a,b,c FROM a) T where t.a > 1; X4l@woh%
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 ^j#rZ;uc
select * from table1 where time between time1 and time2 ~vlype3/EF
select a,b,c, from table1 where a not between 数值1 and 数值2 |w aIpB(
9、说明:in 的使用方法 K*UgX(xu4P
select * from table1 where a [not] in ('值1','值2','值4','值6') W"^wnGa@a
10、说明:两张关联表,删除主表中已经在副表中没有的信息 a<}#HfC;'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]0hrRA`
11、说明:四表联查问题: b306&ZVEk
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 ..... B(xN Gs
12、说明:日程安排提前五分钟提醒 >{\7&}gz
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )XcOl7XLN
13、说明:一条sql 语句搞定数据库分页 %NL^WG:
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 ;bHV
14、说明:前10条记录 ^j-3av=
select top 10 * form table1 where 范围 !aO` AC=5u
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.) ^WBuMCe
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Z87_ #5
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 5p.rwNE
(select a from tableA ) except (select a from tableB) except (select a from tableC) dT,o=8fg
17、说明:随机取出10条数据 "BX!
select top 10 * from tablename order by newid() EdZ\1'&/9
18、说明:随机选择记录 P) 3mX.(}
select newid() .`>y@p!
19、说明:删除重复记录 J{^RkGF
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) E4m`
20、说明:列出数据库里所有的表名 ,|&9M^
select name from sysobjects where type='U' _uc
hU=
21、说明:列出表里的所有的 2^i(gaXUQ
select name from syscolumns where id=object_id('TableName') P ;IrBq6|o
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。 y
WV#Up
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 AL>$HB$
显示结果: Jgnhn>dHe
type vender pcs RV@*c4KvO+
电脑 A 1 Aq3}Ng
电脑 A 1 "*G.EiLq
光盘 B 2 mZd ,
9
光盘 A 2 Kq i4hK
手机 B 3 }.s~T#v
手机 C 3 M|:UwqV>
23、说明:初始化表table1 gz3pX#S
TRUNCATE TABLE table1 {nLjY|*
24、说明:选择从10到15的记录 Qxj JN^Q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,}K<*t[I
[jmd
!.d@L6
O)vp~@|
三、技巧 b0oMs=uBn
1、1=1,1=2的使用,在SQL语句组合时用的较多 -[-wkC8a
"where 1=1" 是表示选择全部 "where 1=2"全部不选, B(M6@1m_
如: ..rOsg{
if @strWhere !=''
"~'b
begin n=[/Z!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Yk=PS[f
end "I(xgx*
else >,td(= :
begin hdrm!aBd
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' z[Xd%mhjO
end P#AW\d^"B
我们可以直接写成 K'GBMnjD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /~3r;M
2、收缩数据库 T?X_c"{8M
--重建索引 R=jI?p
DBCC REINDEX x&0vKo;
DBCC INDEXDEFRAG 6'Fd GS
--收缩数据和日志 qT+%;(
DBCC SHRINKDB X7rMeu
DBCC SHRINKFILE uCcYPvm
3、压缩数据库 U*)8G
dbcc shrinkdatabase(dbname) -,U3fts
4、转移数据库给新用户以已存在用户权限 aTt12Sc
exec sp_change_users_login 'update_one','newname','oldname' F]<Xv"
go {E@Lft-
5、检查备份集 !jTcsN%
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Y=Kc'x[,Zj
6、修复数据库 "men
ALTER DATABASE [dvbbs] SET SINGLE_USER ga`3 (
GO J@u;H$@/y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /{&tY:;m
GO bD?VU<)3
ALTER DATABASE [dvbbs] SET MULTI_USER ml+; Rmvb
GO #)nSr
7、日志清除 P}4QQw
SET NOCOUNT ON ajEjZ6
DECLARE @LogicalFileName sysname, @<elq'2
@MaxMinutes INT, Fx2bwut.K
@NewSize INT yPal<c
USE tablename -- 要操作的数据库名 3qf
Ym}d
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 r [*Vqcz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <_-hRbS
@NewSize = 1 -- 你想设定的日志文件的大小(M) ~Yy>zUH^X
-- Setup / initialize X"fb; sGT
DECLARE @OriginalSize int 5;YMqUkw
SELECT @OriginalSize = size Ck)*&
FROM sysfiles s6@DGSJ
WHERE name = @LogicalFileName ATK_DEAu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6}FP
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + C)`Fv=]R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 85LAYaw
FROM sysfiles z62;cv
WHERE name = @LogicalFileName j3{D^|0bP
CREATE TABLE DummyTrans yjF1}SQ
(DummyColumn char (8000) not null) 7Mg=b%IYs
DECLARE @Counter INT, ci?qT,&
@StartTime DATETIME, 0|{u{w@!`
@TruncLog VARCHAR(255)
@fl-3q
SELECT @StartTime = GETDATE(), ~
Q. 7VDz
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' xwq+j "
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =ACVE;L?
EXEC (@TruncLog) q!|*oUW
-- Wrap the log if necessary. $}!p+$
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired zN^n]N_?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +nJgl8'^y
AND (@OriginalSize * 8 /1024) > @NewSize 2h5nMI]'
BEGIN -- Outer loop. +lHjC$
SELECT @Counter = 0 t%E!o0+8Z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) sTn<#l6
BEGIN -- update hHV";bk
INSERT DummyTrans VALUES ('Fill Log') e,W%uH>X
DELETE DummyTrans NTYg[VTr
SELECT @Counter = @Counter + 1 [PNT\ElT
END ?#}N1k\S
EXEC (@TruncLog) =A83W/4
END pHLB = r
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hEKf6#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Z{]0jhUyNh
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7$CBx/X50)
FROM sysfiles UG+d-&~Ll
WHERE name = @LogicalFileName 5kCUaPu
DROP TABLE DummyTrans v|dBSX9k0
SET NOCOUNT OFF 6WXRP;!Q
8、说明:更改某个表 b4[bL2J$h1
exec sp_changeobjectowner 'tablename','dbo' H9YW
9、存储更改全部表 Y^$X*U/q%U
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Y 0d<~*
@OldOwner as NVARCHAR(128), t gI{`jS%
@NewOwner as NVARCHAR(128) ~?d Nd
AS #h`
V>;
DECLARE @Name as NVARCHAR(128) wl#@lOv-P
DECLARE @Owner as NVARCHAR(128) (|klSz_4LM
DECLARE @OwnerName as NVARCHAR(128) 9\_eK,*B
DECLARE curObject CURSOR FOR ;$.J3!
select 'Name' = name, Egg=yF>T
'Owner' = user_name(uid) X= 5xh
from sysobjects u)}$~E>
where user_name(uid)=@OldOwner UC]\yUK1J
order by name 0IBhb(X
OPEN curObject K,+LG7ec
FETCH NEXT FROM curObject INTO @Name, @Owner ~A'!2
WHILE(@@FETCH_STATUS=0) pNepC<rY
BEGIN xhVO3LW'
if @Owner=@OldOwner jB%lB1Q|
begin n<O}hM ZT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2bw_IT
exec sp_changeobjectowner @OwnerName, @NewOwner !dyXJQ
end 4|riKo)
-- select @name,@NewOwner,@OldOwner E8$20Ue
FETCH NEXT FROM curObject INTO @Name, @Owner /Z'L^L%R
END K|zZS%?$
close curObject 6jE|
deallocate curObject &Sw%<N*r
GO u0|8Tgf
10、SQL SERVER中直接循环写入数据 [>8}J"
declare @i int k/#&qC>]
set @i=1 l;R%= P?'F
while @i<30
M+||rct
begin q&s3wDl/
insert into test (userid) values(@i) ,(d)Qg
set @i=@i+1 Wbr|_W
end !t$'AoVBq
小记存储过程中经常用到的本周,本月,本年函数 r`W)0oxD
Dateadd(wk,datediff(wk,0,getdate()),-1) EofymAi%
Dateadd(wk,datediff(wk,0,getdate()),6) >,gg5<F-E
Dateadd(mm,datediff(mm,0,getdate()),0) x@P y>f2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $PTP/^
Dateadd(yy,datediff(yy,0,getdate()),0) l{I6&^!KS
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ($au:'kU
上面的SQL代码只是一个时间段 x$5) ^ud?
Dateadd(wk,datediff(wk,0,getdate()),-1) UO0{):w>
Dateadd(wk,datediff(wk,0,getdate()),6) iU$] {c2;A
就是表示本周时间段. {.?ZHy\Rk
下面的SQL的条件部分,就是查询时间段在本周范围内的: *H"B _3<n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -]/I73!b
而在存储过程中 #lmB
AL~3
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) t<#mP@Mz=N
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) UQ)W%Y;[0