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。 ATU] KL!{
M}F)
P&Y
I9r> 3?
一、基础 p8u-3
1、说明:创建数据库 RT=(vq @
CREATE DATABASE database-name L/J)OJe\
2、说明:删除数据库 D~<0CQ3n.
drop database dbname }%eXGdC
3、说明:备份sql server ww{07g
--- 创建 备份数据的 device iX'#~eK*<
USE master :.EVvuXI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ZzO.s$
--- 开始 备份 \>XkK<ye
BACKUP DATABASE pubs TO testBack 6~6*(s|]A
4、说明:创建新表 6Yx/m
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {f)"F;]V
根据已有的表创建新表: j%s:d(H`
A:create table tab_new like tab_old (使用旧表创建新表) Kkds^v6
B:create table tab_new as select col1,col2... from tab_old definition only rv97Wm+
5、说明:删除新表 {5gh.
drop table tabname ib)AC,LT
6、说明:增加一个列 Bso3Z ^X.
Alter table tabname add column col type 8(A+"H(
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。 gkDlh{
7、说明:添加主键: Alter table tabname add primary key(col) _"%-=^_
说明:删除主键: Alter table tabname drop primary key(col) `~3y[j]kO
8、说明:创建索引:create [unique] index idxname on tabname(col....) rwou[QU
删除索引:drop index idxname sv?Lk4_
注:索引是不可更改的,想更改必须删除重新建。 js\|xfDxP
9、说明:创建视图:create view viewname as select statement /F6=iHK(l
删除视图:drop view viewname h/n&&J
10、说明:几个简单的基本的sql语句 >)PcK
选择:select * from table1 where 范围 :s OsG&y
插入:insert into table1(field1,field2) values(value1,value2) iPPW_Q9x
删除:delete from table1 where 范围 2f$6}m'Ad
更新:update table1 set field1=value1 where 范围 RBzBR)@5
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U:
Q&sq8U
排序:select * from table1 order by field1,field2 [desc] VlQaT7Q
总数:select count as totalcount from table1 n~NOqvT <
求和:select sum(field1) as sumvalue from table1 a5xp[TlXn.
平均:select avg(field1) as avgvalue from table1 `[Xff24(eb
最大:select max(field1) as maxvalue from table1 A5> ,e|
最小:select min(field1) as minvalue from table1 |cE 69UFB
$>fMu
^h@1t FF
2oFHP_HVfu
11、说明:几个高级查询运算词 As7Y4w* +
mN:p=.&
<
RK`C31Ws
A: UNION 运算符 mxV0"$'Fm
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。 KoNJ;YiKtN
B: EXCEPT 运算符 /Z*XKIU6v/
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。 g4 |s9RMD
C: INTERSECT 运算符 JH;\wfrD
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。 6-<>P E2
注:使用运算词的几个查询结果行必须是一致的。 36U
zfBa
12、说明:使用外连接 ?R}a,k
A、left outer join: gjVKk
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。 )N4_SA
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 #\]:lr{>?4
B:right outer join: _ *O^|QbM
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。 +5+?)8Ls
C:full outer join: n^AQ!wC
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。 2& l~8,
hs"=>(P)
o4"7i 9+g
二、提升 M1/Rba Q
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) q-fxs8+m|
法一:select * into b from a where 1<>1 (
o_lH2
法二:select top 0 * into b from a !5P\5WF~Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _JjR=
m
insert into b(a, b, c) select d,e,f from b; O:Fnxp5@
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) 1c}
%_Z/
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 A%pBvULH
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. / b_C9'S
4、说明:子查询(表名1:a 表名2:b) (hn@+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) ,5_Hen=PI
5、说明:显示文章、提交人和最后回复时间 5@6%/='I q
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Wm/0Y'$r&k
6、说明:外连接查询(表名1:a 表名2:b) *L3>:],7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c bI,gNVN=
7、说明:在线视图查询(表名1:a ) B9RB/vHH
select * from (SELECT a,b,c FROM a) T where t.a > 1; -&u2C}4s
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 &K_"5.7-56
select * from table1 where time between time1 and time2 y[s* %yP3l
select a,b,c, from table1 where a not between 数值1 and 数值2 8)D5loS
9、说明:in 的使用方法 Ck|3DiRQ
select * from table1 where a [not] in ('值1','值2','值4','值6') !kl9X-IiI
10、说明:两张关联表,删除主表中已经在副表中没有的信息 SWYIQ7*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;:[!I ]E0
11、说明:四表联查问题: 2?9SM@nAY
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... EVW{!\8[
12、说明:日程安排提前五分钟提醒 JEK6Ms;)A
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 w}<CH3cx
13、说明:一条sql 语句搞定数据库分页 ^f-?xXPx
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Q}N.DM@d3
14、说明:前10条记录 h98_6Dw(]
select top 10 * form table1 where 范围 =W6AUN/%p
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) RY(\/W#$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q}a 1P8?S
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 S'NZb!1+
(select a from tableA ) except (select a from tableB) except (select a from tableC) X/_e#H0
17、说明:随机取出10条数据 w~eF0{h
select top 10 * from tablename order by newid() QGYO{S
18、说明:随机选择记录 ?X1vU0c
select newid() uj_ OWre
19、说明:删除重复记录 DA_[pR
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Sxrbhnx
20、说明:列出数据库里所有的表名 4,!S?:7
select name from sysobjects where type='U' )pS1yYLj
21、说明:列出表里的所有的 4 |ryt4B
select name from syscolumns where id=object_id('TableName') aD aQ7i
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。 0B^0,d(s
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 CF`tNA3fxm
显示结果: ik@g; >pQD
type vender pcs MVW2%6
电脑 A 1 7T]}<aK<c[
电脑 A 1 dsKEWZ
=
光盘 B 2 3McBTa!
光盘 A 2 \>8"r,hG|
手机 B 3 .D^=vuxt~
手机 C 3 7(m4,l+(
23、说明:初始化表table1 Vj7(6'Hg
TRUNCATE TABLE table1 f -N:
24、说明:选择从10到15的记录 2t3'"8xJ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc em
&wbe^Wp
7-"ml\z
\$o!M1j
三、技巧 uFM]4v3
1、1=1,1=2的使用,在SQL语句组合时用的较多 h2 2-vX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, T-)Ur/qp
如: @;iW)a_M
if @strWhere !='' 6% @@~"
begin }+KSZ,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere n{dl-P
end fLj#+h-!
else t{\FV@R
begin TbqED\5@9w
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' bDa(@QJ-
end #{)=%5=c
我们可以直接写成 =}Np0UP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )1%l$W
2、收缩数据库 `B{N3Kxbp
--重建索引 [HJ^'/bB'
DBCC REINDEX >y C1X|d~t
DBCC INDEXDEFRAG +$KUy>
--收缩数据和日志 Np4';H
DBCC SHRINKDB Hmt}@
DBCC SHRINKFILE DBuvbq-
3、压缩数据库 KJPCO0"
dbcc shrinkdatabase(dbname) \$Xo5f<
4、转移数据库给新用户以已存在用户权限 12\h| S~
exec sp_change_users_login 'update_one','newname','oldname' !Pf_he
go T6[];|%W
5、检查备份集 F6*n,[5(
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' yUF<qB
6、修复数据库 -s`/5kD
ALTER DATABASE [dvbbs] SET SINGLE_USER -/:N&6eRb
GO S}Wj+H;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK qJ=4HlLno
GO gVM9*3LH6
ALTER DATABASE [dvbbs] SET MULTI_USER 0oI3Fb;E
GO 0FrmZ$
7、日志清除 /3F4t
V
SET NOCOUNT ON Az29?|e
DECLARE @LogicalFileName sysname, H]V@Q~?e
@MaxMinutes INT, 5;wA7@
@NewSize INT #9Z\jW6b
USE tablename -- 要操作的数据库名 0?} ),8v>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 MA\"JAP/
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (9hCO-r
@NewSize = 1 -- 你想设定的日志文件的大小(M) (0jT#&#
-- Setup / initialize rPoPs@CBD
DECLARE @OriginalSize int vdFy}#X
SELECT @OriginalSize = size ?;pw*s1Atz
FROM sysfiles `y5?lS*
WHERE name = @LogicalFileName C~PrIM?
SELECT 'Original Size of ' + db_name() + ' LOG is ' + lf4V;|!^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4,CQJ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' OOy]:t4 /
FROM sysfiles .
:Q[Z
WHERE name = @LogicalFileName J0BA@jH5
CREATE TABLE DummyTrans %$/t`'&o-
(DummyColumn char (8000) not null) QiB^U^f
DECLARE @Counter INT, q:4 51 C
@StartTime DATETIME, x8i;uH\8
@TruncLog VARCHAR(255) iaAVGgA9+
SELECT @StartTime = GETDATE(), gUf-1#g4\`
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8?ldD
DBCC SHRINKFILE (@LogicalFileName, @NewSize) q_eGY&M
EXEC (@TruncLog) cn&\q.!fh
-- Wrap the log if necessary. ]~g6#@l
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !+tz<9BBY
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) m\>531&
AND (@OriginalSize * 8 /1024) > @NewSize U)~?/s{v
BEGIN -- Outer loop. w5 nzS)B:u
SELECT @Counter = 0 MP/6AAt7=|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) CL{R.OA
BEGIN -- update XXsN)2
INSERT DummyTrans VALUES ('Fill Log') *-~B{2b<
DELETE DummyTrans aIV(&7KT4
SELECT @Counter = @Counter + 1 T =r7FU
END BgLW!|T[
EXEC (@TruncLog) 40}qf}8n t
END w
'?xewx
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &z[39Q{~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + NF`WA-W8@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' t_HS0rxG
FROM sysfiles .#zmX\a
WHERE name = @LogicalFileName f\O)+Vc
DROP TABLE DummyTrans asT:/z0
SET NOCOUNT OFF _"
0VM>
8、说明:更改某个表 7'pCFeA>=T
exec sp_changeobjectowner 'tablename','dbo' &{${ Fq
9、存储更改全部表 LB}y,-vX>
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch '<"eG!O
@OldOwner as NVARCHAR(128), #g,JNJ}
@NewOwner as NVARCHAR(128) `6:;*#jO,
AS 40cgsRa|
DECLARE @Name as NVARCHAR(128) t]?u<KD<
DECLARE @Owner as NVARCHAR(128) x
;V7D5 q
DECLARE @OwnerName as NVARCHAR(128) fx@Hd!nO~"
DECLARE curObject CURSOR FOR P$z8TDCH
select 'Name' = name, 6'6"Ogu%'
'Owner' = user_name(uid) 5~Vra@iab:
from sysobjects "Sp+Q&2U
where user_name(uid)=@OldOwner | k"?I
order by name d&K2\n
OPEN curObject )SG+9!AbMZ
FETCH NEXT FROM curObject INTO @Name, @Owner @T53%v<5
WHILE(@@FETCH_STATUS=0) b~?FV>gl
BEGIN m1DzUq;
if @Owner=@OldOwner :A%|'HxH3
begin G0p|44_~t
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &9bsTm
exec sp_changeobjectowner @OwnerName, @NewOwner k2Yh?OH
end !~5;Jb>s[/
-- select @name,@NewOwner,@OldOwner HMsTm}d
FETCH NEXT FROM curObject INTO @Name, @Owner `OzcL
END TCAtb('D
close curObject X;JptF^
deallocate curObject U
X)k;h
GO %_xRS
10、SQL SERVER中直接循环写入数据 siveqz6h
declare @i int 4qq+7B
set @i=1 $]:ycn9l
while @i<30 2O\p`,.
begin jt|e?1:vF
insert into test (userid) values(@i) $_s"16s
set @i=@i+1 l
\~w(8g<A
end k(|D0%#b7
小记存储过程中经常用到的本周,本月,本年函数 69{^Vfd;Y
Dateadd(wk,datediff(wk,0,getdate()),-1) 1U[8OM{$
Dateadd(wk,datediff(wk,0,getdate()),6) uM"G)$I\
Dateadd(mm,datediff(mm,0,getdate()),0) s5? 1w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) iB#xUSkS
Dateadd(yy,datediff(yy,0,getdate()),0) ^CZ!rOSv
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) (jYHaTL6Y'
上面的SQL代码只是一个时间段 S;#S3?G
Dateadd(wk,datediff(wk,0,getdate()),-1) @,
v'V!
Dateadd(wk,datediff(wk,0,getdate()),6) (`+%K_
就是表示本周时间段. R2kR
下面的SQL的条件部分,就是查询时间段在本周范围内的: #({0HFSC:j
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?f!w:zp
而在存储过程中 4B>N[#-0=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 8>" vAEf
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) bdh6ii