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。 K$]QzPXS
sy`s$Ed!
}dHiW:J>
一、基础 y?JbJ
1、说明:创建数据库 :I$2[K
CREATE DATABASE database-name g.]'0)DMW
2、说明:删除数据库 E+)Go-rS(
drop database dbname ^~aSrREo
3、说明:备份sql server G;m"ao"2
--- 创建 备份数据的 device L%0lX$2&\
USE master Ih7Eq/iu
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~"mZ0E
--- 开始 备份 #Kl2K4
BACKUP DATABASE pubs TO testBack (=/F=,w
4、说明:创建新表 8<kme"%s
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _+N^yw ,r*
根据已有的表创建新表: J:u|8>;
A:create table tab_new like tab_old (使用旧表创建新表) @ 7?_Yw
B:create table tab_new as select col1,col2... from tab_old definition only +i^s\c!3;
5、说明:删除新表 w!}1oy
drop table tabname .+Ej%|l%
6、说明:增加一个列 c7F&~RLC
Alter table tabname add column col type ' XF`&3i
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 752wK|o0|;
7、说明:添加主键: Alter table tabname add primary key(col) Q]wM/7
说明:删除主键: Alter table tabname drop primary key(col) (M+<^3c
8、说明:创建索引:create [unique] index idxname on tabname(col....) nnG2z@$-
删除索引:drop index idxname xu=B
注:索引是不可更改的,想更改必须删除重新建。 #CPP dU$
9、说明:创建视图:create view viewname as select statement `X='g96C1
删除视图:drop view viewname 'y?|shV{]
10、说明:几个简单的基本的sql语句 2eU[*x
选择:select * from table1 where 范围 `I8^QcP
插入:insert into table1(field1,field2) values(value1,value2) V,+[XB
删除:delete from table1 where 范围 o"FiM5L^.
更新:update table1 set field1=value1 where 范围 #Qr4Ke$g[l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
nvPE
N
排序:select * from table1 order by field1,field2 [desc] D5pF:~tQ(j
总数:select count as totalcount from table1 `z_7[$\~
求和:select sum(field1) as sumvalue from table1 m0Syxb
平均:select avg(field1) as avgvalue from table1 +q/h:q.TV
最大:select max(field1) as maxvalue from table1 [M^[61
最小:select min(field1) as minvalue from table1 mi<D
bnou
Pm^N0L9?q
#/Fu*0/)`
N1~V +_mM
11、说明:几个高级查询运算词 ~n^G<iXLp
#(
sNk,^Ax
&a_kJ)J
A: UNION 运算符 qffSq](D.
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。 8-a6Q|
B: EXCEPT 运算符 &H&P)Px*_
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。 K$cIVsfr
C: INTERSECT 运算符 8 tygs
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ?=!XhU
.
注:使用运算词的几个查询结果行必须是一致的。 NNwd;AC
12、说明:使用外连接 Kk>qgi$
A、left outer join: n u8j_grW
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。 %hbLT{w
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 *+j{9LK
B:right outer join: I'9s=~VfY,
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。 g0j4<\F2\
C:full outer join: OgN1{vRFx
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
^h-pd
G>,nZ/,A{
'[ g)v
二、提升 iW@Vw{|i I
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "qTC(F9N$.
法一:select * into b from a where 1<>1 "QO/Jls
法二:select top 0 * into b from a 2c~?UK[1
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @k+G
Cf
insert into b(a, b, c) select d,e,f from b; y3nm!tjyM
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) 7ml0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |SP.S 0.y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Ui|a}`c
4、说明:子查询(表名1:a 表名2:b) '}+X,Usm
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) 3{4/7DcX
5、说明:显示文章、提交人和最后回复时间 #* gU[9U~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b '<D `:srV
6、说明:外连接查询(表名1:a 表名2:b) DV[ Jbl:)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [Ht."VxR
7、说明:在线视图查询(表名1:a ) 5uV"g5?w
select * from (SELECT a,b,c FROM a) T where t.a > 1; rrY{Jf9>
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 !^l4EL5#
select * from table1 where time between time1 and time2 i9\\evJs
select a,b,c, from table1 where a not between 数值1 and 数值2 !+A"Lej
9、说明:in 的使用方法 :uwRuPI
select * from table1 where a [not] in ('值1','值2','值4','值6') {#*? S>DA
10、说明:两张关联表,删除主表中已经在副表中没有的信息 rZ.a>'T4
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }1]!#yMfq
11、说明:四表联查问题: ]v@ tZ}
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 ..... 9{%g-u\
12、说明:日程安排提前五分钟提醒 *%N7QyO`I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 P\X=*
13、说明:一条sql 语句搞定数据库分页 +/3
Z
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 0"kE^=
14、说明:前10条记录 o?va#/fk
select top 10 * form table1 where 范围 `F2*o47|t
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.) ]\a\6&R
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {rb-DB-/5M
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 EK8E
(select a from tableA ) except (select a from tableB) except (select a from tableC) XJJ[F|k~
17、说明:随机取出10条数据 nrS[7~
select top 10 * from tablename order by newid() [)H,zpl
18、说明:随机选择记录 ?BDlB0jxzi
select newid() mF*?e/
19、说明:删除重复记录 *H%0Gsk
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) b>bgUDq
20、说明:列出数据库里所有的表名
&6\r
select name from sysobjects where type='U' ?79SP p)oo
21、说明:列出表里的所有的 5xMA~I 0c
select name from syscolumns where id=object_id('TableName') z^P* :
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。 J\xz^%p
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 <t[Z9s$n
显示结果: 1=/doo{^
type vender pcs hB
P$9GR
电脑 A 1 r;cI}'
电脑 A 1 d^Zo35X
光盘 B 2 *h*j%
光盘 A 2 *#Lsjk~_-
手机 B 3 sd]54&3A
手机 C 3 iJ`%yg,
23、说明:初始化表table1 3yHb!}F
TRUNCATE TABLE table1 *`+<x
24、说明:选择从10到15的记录 T.Pklty
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p|h.@do4
79{.O`v
[!J
@a
`7QvwXsH]
三、技巧 J ?ztn
1、1=1,1=2的使用,在SQL语句组合时用的较多 +,&m7L
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 9tzoris[~
如: saGRP}7?
if @strWhere !='' ,]~u:Y}
begin DO7-=74=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Jh37pI
end 8%;}LK
else OLk9A
begin l5FuMk-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Q3'fz 9v
end iEiu%T>
我们可以直接写成 tt+>8rxF:;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere c=b+g+*xd
2、收缩数据库 dV5PhP>6
--重建索引 c@RT$Q9j
DBCC REINDEX ]LEoOdDN"C
DBCC INDEXDEFRAG BCBEX&0hk{
--收缩数据和日志 %/UV_@x&
DBCC SHRINKDB p&i.)/
DBCC SHRINKFILE ! 9d_Gf-
3、压缩数据库 jMN)?6$=
dbcc shrinkdatabase(dbname) mSU@UD|'
4、转移数据库给新用户以已存在用户权限 Sp 7u_Pq{
exec sp_change_users_login 'update_one','newname','oldname' lbQ6
a
go S:/{
5、检查备份集 yJDeX1+,
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3.Ji5~
6、修复数据库 %9t{Z1$
ALTER DATABASE [dvbbs] SET SINGLE_USER j(0Ilx|7v
GO seu
~'s-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK YSqv86
GO <KKDu$W|T
ALTER DATABASE [dvbbs] SET MULTI_USER F(d:t!
GO D,c!#(v cK
7、日志清除 sB?2*S"X)<
SET NOCOUNT ON MMMqG`Px
DECLARE @LogicalFileName sysname, ?Fce!J
@MaxMinutes INT, GHv{
@NewSize INT $[[?;g
USE tablename -- 要操作的数据库名 p= {Jf}v
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 K'x4l,rq
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Takt_N
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3I|O^
-- Setup / initialize vwVVBG;t
DECLARE @OriginalSize int <O.Kqk*
nq
SELECT @OriginalSize = size cC'
~
FROM sysfiles 4avc=Y5
WHERE name = @LogicalFileName K]X`sH:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + im8
-7Xt
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _l<mu? "
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' R<|ejw
FROM sysfiles U2bzUxK
WHERE name = @LogicalFileName kQLT$8io
CREATE TABLE DummyTrans (%bE~Q2P*<
(DummyColumn char (8000) not null) A#(`9
DECLARE @Counter INT, 3E,DipHg
@StartTime DATETIME, :s"2Da3B
@TruncLog VARCHAR(255) z$|;-u|
SELECT @StartTime = GETDATE(), #F!Kxks
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' qz`rL#W]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) qEQAn/&
EXEC (@TruncLog) MWs~#ReZ
-- Wrap the log if necessary. +< yhcSSTB
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired X'x3esw w
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) V.8%|-d
AND (@OriginalSize * 8 /1024) > @NewSize MU1E_"Z)
BEGIN -- Outer loop. XFQNr`
SELECT @Counter = 0 o\4CoeG
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4z_n4=
BEGIN -- update hsz^rZ
INSERT DummyTrans VALUES ('Fill Log') Ns<?b;aK
DELETE DummyTrans 8}BS2C%P
SELECT @Counter = @Counter + 1 _{$fA6C
END ;1`!wG-DD
EXEC (@TruncLog) a8Uk[^5
END b9 uBdo@o
SELECT 'Final Size of ' + db_name() + ' LOG is ' + OxQYNi2
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Xwq]f:@V
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #!})3_Qc(y
FROM sysfiles CxDcY
WHERE name = @LogicalFileName w2OsLi Sv
DROP TABLE DummyTrans NYB "jKMk
SET NOCOUNT OFF I9&lO/c0
8、说明:更改某个表 f*m[|0qI<X
exec sp_changeobjectowner 'tablename','dbo' '#D8*OP^
9、存储更改全部表 ar$*a>'?
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ".P){Dep$4
@OldOwner as NVARCHAR(128), ! E0!-UpY
@NewOwner as NVARCHAR(128) ',)7GY/n~
AS (0L=AxH
DECLARE @Name as NVARCHAR(128) d1]i,C~Y
DECLARE @Owner as NVARCHAR(128) dJD(\a>r.u
DECLARE @OwnerName as NVARCHAR(128) 6kR\xP]Kr
DECLARE curObject CURSOR FOR {^m Kvc
select 'Name' = name, sgAzL
'Owner' = user_name(uid) e2w&&B-
from sysobjects (=c1
where user_name(uid)=@OldOwner vzXag*0
order by name ss
iok LE
OPEN curObject "2{%JFE
FETCH NEXT FROM curObject INTO @Name, @Owner pC(sS0J
WHILE(@@FETCH_STATUS=0) uMmXs%9T
BEGIN I=Ijdwb H
if @Owner=@OldOwner ;Vu5p#,O<M
begin FTf<c0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0*F}o)n/m
exec sp_changeobjectowner @OwnerName, @NewOwner :iPym}CE
end Riry_
-- select @name,@NewOwner,@OldOwner %j+xgX/&
FETCH NEXT FROM curObject INTO @Name, @Owner }]6f+
END FvdeQsc!
close curObject NM#-Af*pg
deallocate curObject Q(Gl{#b
GO )uheV,ZnY
10、SQL SERVER中直接循环写入数据 T
.n4TmF
declare @i int Or0O/\D)
set @i=1 9Q.#\
while @i<30 u2iXJmM*
begin t ^SzqB
insert into test (userid) values(@i) 0
n
vSvk
set @i=@i+1 ](jFwxU
end _$s> c!t,#
小记存储过程中经常用到的本周,本月,本年函数
F0lOlS
Dateadd(wk,datediff(wk,0,getdate()),-1) bt/ =Kq#
Dateadd(wk,datediff(wk,0,getdate()),6) 7cTk@Gq
Dateadd(mm,datediff(mm,0,getdate()),0) %)(Cp-b!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZH 6\><My
Dateadd(yy,datediff(yy,0,getdate()),0) rS8 w\`_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |>
enp>
上面的SQL代码只是一个时间段 quxdG>8
Dateadd(wk,datediff(wk,0,getdate()),-1) v|';!p|
Dateadd(wk,datediff(wk,0,getdate()),6) yxWO[ Z
就是表示本周时间段. 0<p{BL8
下面的SQL的条件部分,就是查询时间段在本周范围内的: (eWPis[
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $ &UZy|9
而在存储过程中 pY"O9x
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +9;2xya2
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *%5{'