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。 Bh=t%#y|`
(["kbPma
N7lg6$s Aj
一、基础 iE"]S )
1、说明:创建数据库 duEXp]f!
CREATE DATABASE database-name TxF^zx\
2、说明:删除数据库 (c)/&~aE
drop database dbname )e3w-es~4
3、说明:备份sql server WM|G/'q
--- 创建 备份数据的 device B7'#8heDh
USE master oH0g>E;
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Izu____
--- 开始 备份 /}E2Rr?{
BACKUP DATABASE pubs TO testBack RN)XIf$@_
4、说明:创建新表 Q >[>{N&\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9Jh&C5\\
根据已有的表创建新表: yOEy3d=*
A:create table tab_new like tab_old (使用旧表创建新表) 'J} ?'{.
B:create table tab_new as select col1,col2... from tab_old definition only t27UlFX
5、说明:删除新表 k;cX,*DIn
drop table tabname )-[$m%
6、说明:增加一个列 d'MZ%.#
Alter table tabname add column col type cS YCMQ1ro
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "1Hn?4nz5
7、说明:添加主键: Alter table tabname add primary key(col) {0F/6GwUC
说明:删除主键: Alter table tabname drop primary key(col) PRiE2Di2S
8、说明:创建索引:create [unique] index idxname on tabname(col....) Xykoq"dbb
删除索引:drop index idxname pJ8F+`*
注:索引是不可更改的,想更改必须删除重新建。 OW};i|
9、说明:创建视图:create view viewname as select statement \jk*Nm8;
删除视图:drop view viewname ]QJ5JtD-
10、说明:几个简单的基本的sql语句 k%~;mu"4}
选择:select * from table1 where 范围 }G{"Mp4
插入:insert into table1(field1,field2) values(value1,value2) 8Pd9&/Y
删除:delete from table1 where 范围 S'|PA7a}h
更新:update table1 set field1=value1 where 范围 ,^e2ma|z
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "AjC2P],
排序:select * from table1 order by field1,field2 [desc] sS{Co8EJn
总数:select count as totalcount from table1 u
`xQC/
求和:select sum(field1) as sumvalue from table1 y lczM^@
平均:select avg(field1) as avgvalue from table1 \Db`RvEmR
最大:select max(field1) as maxvalue from table1 VOr:G85*s
最小:select min(field1) as minvalue from table1 3s%DF,
#J/RI[a
D`G; C
FXT^r3
11、说明:几个高级查询运算词 u*%mUh
H0OO+MCe
<ivG(a*=]
A: UNION 运算符 qZ>_{b0f
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ?QFxds
B: EXCEPT 运算符 +`"Tn`O
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 0#'MR.,
C: INTERSECT 运算符 {Lv"wec*x
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 o<lmU8xB=
注:使用运算词的几个查询结果行必须是一致的。 |;|r[aU
12、说明:使用外连接 bnL!PsG$K,
A、left outer join: $s1/Rmw
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。 '")'h
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 ;lE=7[UJ3X
B:right outer join: T.z efoZ
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。 |95K
C:full outer join: 2K/t[.8
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。 *iru>F8r:
aJ=)5%$6kc
5#|&&$)
二、提升 ddl]!
^IK
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l%Ke>9C
法一:select * into b from a where 1<>1 6:}n}q,V
法二:select top 0 * into b from a g*FHZM*N9
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) T[e+iv<8j
insert into b(a, b, c) select d,e,f from b; @6~m&$R/
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) URj)]wp/
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 JDa_;bqL
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1Z_w2D*
4、说明:子查询(表名1:a 表名2:b) {G3Ok++hc
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) &x*l{s[
5、说明:显示文章、提交人和最后回复时间 \rh+\9(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b dzbbFvG
6、说明:外连接查询(表名1:a 表名2:b) njJTEUd">
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Cz5U
7、说明:在线视图查询(表名1:a ) XD6Kp[s
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6*$A/D
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 lUq`tK8
select * from table1 where time between time1 and time2 v;z8g^L
select a,b,c, from table1 where a not between 数值1 and 数值2 U3]/ NV*
9、说明:in 的使用方法 n87Uf$
select * from table1 where a [not] in ('值1','值2','值4','值6') /8:e|
]
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]YZ_kc^(V;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 6&~Z3|<e
11、说明:四表联查问题: e$QMR.'
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 ..... 3zfiegY@wm
12、说明:日程安排提前五分钟提醒 |Om][z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,f?B((l
13、说明:一条sql 语句搞定数据库分页 =kq<J-:#R
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 "IJ1b~j?
14、说明:前10条记录 32j#kJ W
select top 10 * form table1 where 范围 <ldArZ4C4
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.) 07(LLhk@d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 75P!`9bE
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 [zP}G?(
(select a from tableA ) except (select a from tableB) except (select a from tableC) "tmu23xQ
17、说明:随机取出10条数据 * >NML]#0
select top 10 * from tablename order by newid() ~(c<M>Q8
18、说明:随机选择记录 :*l\j"fX5
select newid() $_HyE%F#
19、说明:删除重复记录 QDK }e:4q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) bFA
lC
20、说明:列出数据库里所有的表名 06pY10<>X
select name from sysobjects where type='U' BdvpG
21、说明:列出表里的所有的 u
XZ ;K.
select name from syscolumns where id=object_id('TableName') `5x0p a
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 wB[
JFy"E
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type )g-0b@z!n
显示结果: Kp;<z<
type vender pcs Y!(w. G
电脑 A 1 H-m).^
电脑 A 1 4w 7vgB
光盘 B 2 JAwEu79sh
光盘 A 2 U+D#
手机 B 3 cI7a TLC"s
手机 C 3 VqOTrB1w/
23、说明:初始化表table1 cqb6]
TRUNCATE TABLE table1 WdJeh:h
24、说明:选择从10到15的记录 ?^8.Sa{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2of+KI:
.lz=MUR
@'J~(#}
Ym-mfWo^#
三、技巧 *li5/=UC5*
1、1=1,1=2的使用,在SQL语句组合时用的较多 d-8g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, sv\=/F@n
如: 4!M0)Nix
if @strWhere !='' kZ^wc .
begin ,mD$h?g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BSEP*#s
end KWw?W1H
else dr"@2=Z
begin MLDAr dvK
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X5Y. o&
end Tkh?F5l
我们可以直接写成 ciPq@kMV
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Dx P65wU
2、收缩数据库 [s-!tE3-
--重建索引 )d=&X|S>
DBCC REINDEX V4g vKWc
DBCC INDEXDEFRAG 8vvNn>Q
--收缩数据和日志 n4AQ
DBCC SHRINKDB QP6a,^];
DBCC SHRINKFILE aQ1n1OBr
3、压缩数据库 dpcv'cRfw
dbcc shrinkdatabase(dbname) ,z$U=uo
4、转移数据库给新用户以已存在用户权限 **n109R
exec sp_change_users_login 'update_one','newname','oldname' UzkX;UA
go hl+
T
5、检查备份集 E{B40E~4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +|O&k
6、修复数据库 I9cZZ`vs
ALTER DATABASE [dvbbs] SET SINGLE_USER rf2-owWN
GO &<5oDdC
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZV:0:k.x
GO ?uE@C3 e
ALTER DATABASE [dvbbs] SET MULTI_USER `lE8dwL
GO /}-LaiS
7、日志清除 x#tP)5n?s*
SET NOCOUNT ON Ktf lbI!
DECLARE @LogicalFileName sysname, g
_u
@MaxMinutes INT, t. kOR<
@NewSize INT t=r*/DxX=
USE tablename -- 要操作的数据库名 -Wl79lE
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9jt+PII
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =a./HCF
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0$q)uip
-- Setup / initialize _O>8jH!#
DECLARE @OriginalSize int B#x.4~YX
SELECT @OriginalSize = size }tH6E
FROM sysfiles q*K.e5"'
WHERE name = @LogicalFileName {rZ )!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + kT4Tb%7KM
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R;2
Z~P
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \MFjb IL
FROM sysfiles s4{ >7`N2
WHERE name = @LogicalFileName I> 3]VRi
CREATE TABLE DummyTrans 6
VuMx7W1
(DummyColumn char (8000) not null) ^
Nm!b
DECLARE @Counter INT, 8Ir
= @
@StartTime DATETIME, JG!@(lr
@TruncLog VARCHAR(255) XSz)$9~hk
SELECT @StartTime = GETDATE(), 4BAG GD2
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' +HNM$yp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;R{ffS6
EXEC (@TruncLog) $23dcC*hI
-- Wrap the log if necessary. 4z> SI\Ss
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Eh&HN-&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) DS1_hbk
AND (@OriginalSize * 8 /1024) > @NewSize =-|,v*
BEGIN -- Outer loop. "AUHe6Yv
SELECT @Counter = 0 ^5BQ=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) eUE(vn#
BEGIN -- update ]<IK0
INSERT DummyTrans VALUES ('Fill Log') X[KHI1@w
DELETE DummyTrans As-xO~ +
SELECT @Counter = @Counter + 1 @fG'X
END %T'<vw0
EXEC (@TruncLog) Z.
G<'
END N.@@ebuE
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :927y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + TQg~I/
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U[t/40W}P
FROM sysfiles eT6T@C](
WHERE name = @LogicalFileName 'WQ?%da
DROP TABLE DummyTrans XPQY*.l&.
SET NOCOUNT OFF "8sB,$
8、说明:更改某个表 r>ca17
exec sp_changeobjectowner 'tablename','dbo' T1_>qnSz
9、存储更改全部表 ?,0 a#lG
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5VR=D\j
@OldOwner as NVARCHAR(128), >s|zrS)
@NewOwner as NVARCHAR(128) ]
g]^^
AS Y~[k_!
DECLARE @Name as NVARCHAR(128) ztb?4f q6)
DECLARE @Owner as NVARCHAR(128) nBJ'ak
DECLARE @OwnerName as NVARCHAR(128) ~duF2m 72
DECLARE curObject CURSOR FOR c1aIZ
select 'Name' = name, urK~]68
'Owner' = user_name(uid) {7Q)2NC
from sysobjects {q1u[T&r
where user_name(uid)=@OldOwner f'?FYBL
order by name <<l1zEf@
OPEN curObject OH/!Ky\@
FETCH NEXT FROM curObject INTO @Name, @Owner zW9/[Db
WHILE(@@FETCH_STATUS=0) VtnVl`/]
BEGIN hYB3tT
if @Owner=@OldOwner !\Vc#dslt
begin
5VZZk%oy
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2D)B%nM[
exec sp_changeobjectowner @OwnerName, @NewOwner 3}kG ]#
end ^i8"eF
-- select @name,@NewOwner,@OldOwner yB2}[1
FETCH NEXT FROM curObject INTO @Name, @Owner ( we)0AxF'
END oF L7dL
close curObject dwJnPJ=z
deallocate curObject b>]k=zd
GO $q*hE&x
Qd
10、SQL SERVER中直接循环写入数据 nAaY5s0D
declare @i int g$h`.Fk,
set @i=1 _?v&\j
while @i<30 8@,8j!$8G
begin z07Xj%zX9
insert into test (userid) values(@i) P"f4`q
set @i=@i+1 Dgc}T8R
end 7!/!a*zg
小记存储过程中经常用到的本周,本月,本年函数 9 iV_
Dateadd(wk,datediff(wk,0,getdate()),-1) .H
9r_
Dateadd(wk,datediff(wk,0,getdate()),6) +$$5Cv5#<&
Dateadd(mm,datediff(mm,0,getdate()),0) ~$d(@T&
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %E2V$l0
Dateadd(yy,datediff(yy,0,getdate()),0) O-&^;]ieJ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |.;*,bb|3
上面的SQL代码只是一个时间段 H5Bh?mw2
Dateadd(wk,datediff(wk,0,getdate()),-1) hip't@.uE
Dateadd(wk,datediff(wk,0,getdate()),6) <f#pS[A
就是表示本周时间段. sB8v:
下面的SQL的条件部分,就是查询时间段在本周范围内的: L$6W,D
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?7uK:'8
而在存储过程中 9#E)H?`g
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ),J6:O&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =[,EFkU?B