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。 ~i
\69q%
]?r8^L yZ4
(ZnA#%
一、基础 @sDd:>t
1、说明:创建数据库 Z-Uq89[HZ
CREATE DATABASE database-name W1OGN4`C
2、说明:删除数据库 arB$&s
drop database dbname M3Z yf
3、说明:备份sql server UY+~xzm
--- 创建 备份数据的 device +)|2$$m
USE master {p-%\nOC
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X;1q1X)K
--- 开始 备份 ;2iZX=P`n
BACKUP DATABASE pubs TO testBack TnG"_VK9R
4、说明:创建新表 IV*}w"r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) p+t8*lkq
根据已有的表创建新表: {T IGPK
A:create table tab_new like tab_old (使用旧表创建新表) i~2>kxf;K1
B:create table tab_new as select col1,col2... from tab_old definition only t@ Jo ?0s
5、说明:删除新表 ``SjALf
drop table tabname 7Ct m({I-
6、说明:增加一个列 E,r PM
Alter table tabname add column col type )#Id2b~
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。 UJZa1p@L
7、说明:添加主键: Alter table tabname add primary key(col) {R#nGsrt;
说明:删除主键: Alter table tabname drop primary key(col) IP >An8+
8、说明:创建索引:create [unique] index idxname on tabname(col....) :!/}*B
删除索引:drop index idxname <Z&gAqj 2
注:索引是不可更改的,想更改必须删除重新建。 l]ZUKy
9、说明:创建视图:create view viewname as select statement \)v.dQ!
删除视图:drop view viewname !nu['6I%
10、说明:几个简单的基本的sql语句 l>G#+#{
选择:select * from table1 where 范围 M}c_KFMV
插入:insert into table1(field1,field2) values(value1,value2) X#o:-FKf
删除:delete from table1 where 范围 OT [t
EqQ
更新:update table1 set field1=value1 where 范围 BgRiJFa.d[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! KGJB.<Be
排序:select * from table1 order by field1,field2 [desc] wO"Q{oi+
总数:select count as totalcount from table1 nQ+{1 C
求和:select sum(field1) as sumvalue from table1 MT*b+&1e
平均:select avg(field1) as avgvalue from table1 48DsRy
最大:select max(field1) as maxvalue from table1 k X-AC5]
最小:select min(field1) as minvalue from table1 vr;7p[~
jzV#%O{`
V>%%2"&C
"Vh(%N`6
11、说明:几个高级查询运算词 LU]~d<i99
hImCy9i}
v`fUAm/
A: UNION 运算符 QXrK-&fju
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。 C]`Y PM5
B: EXCEPT 运算符 qN) cB?+
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。 4$J/e?i
C: INTERSECT 运算符 QSLDA`
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。 w\M_3}
注:使用运算词的几个查询结果行必须是一致的。 q&M;rIo?
12、说明:使用外连接 Vg3&:g5 /
A、left outer join: (tz! "K
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。 x4.
#_o&
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 `+gF|o9
B:right outer join: uZ^i8;i
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。 J@5 OZFMZ
C:full outer join: 0uvL,hF
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。 sPw(+m*C
jlB3BwG{w
^KlOD_GN|
二、提升 h~1QmEat
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9W8Dp?:
法一:select * into b from a where 1<>1 8}0
D?
法二:select top 0 * into b from a "~
`-Jkm
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) fG{oi(T
insert into b(a, b, c) select d,e,f from b; 07#!b~N
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) Hy6Np62
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,|H!b%ZW
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~%
c->\Q
4、说明:子查询(表名1:a 表名2:b) 9+/|sU\.%
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) 1@ina`!1O
5、说明:显示文章、提交人和最后回复时间 u>E+HxUJ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b &yN<@.
6、说明:外连接查询(表名1:a 表名2:b) NanU%#&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?R+$4;iy
7、说明:在线视图查询(表名1:a ) %{{#Q]]&
select * from (SELECT a,b,c FROM a) T where t.a > 1; aZ^lI
6@+4
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 83h3C EQ
select * from table1 where time between time1 and time2 &qC>*X.
select a,b,c, from table1 where a not between 数值1 and 数值2 pg<>Ow5,~l
9、说明:in 的使用方法 3k/MigT
select * from table1 where a [not] in ('值1','值2','值4','值6') Q4x71*vy
10、说明:两张关联表,删除主表中已经在副表中没有的信息 V OX>Sl
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @|@43}M]C-
11、说明:四表联查问题: D%A-& =
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
c[I,Sveq
12、说明:日程安排提前五分钟提醒 e'6?iLpy
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ..t=Y#
13、说明:一条sql 语句搞定数据库分页 8a h]D
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 r:IU+3
14、说明:前10条记录 OTm`i>rB
select top 10 * form table1 where 范围 r3kI'I|bq
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) RoTT%c P_
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )t4C*+9<U
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 V;V9_qP,
(select a from tableA ) except (select a from tableB) except (select a from tableC) c1^3lgPv
17、说明:随机取出10条数据 p
c],H
select top 10 * from tablename order by newid() +D@R'$N
18、说明:随机选择记录 ?,NAihN]
select newid() oW_WW$+N
19、说明:删除重复记录 tFwlx3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) p5KNqqZZ
20、说明:列出数据库里所有的表名 W@tLT[}CG
select name from sysobjects where type='U' +M*a.ra0OF
21、说明:列出表里的所有的 HL?pnT09
select name from syscolumns where id=object_id('TableName') YV
msWuF
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 uv5@Alm
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type E;sltl
显示结果: fCfY.vd5
type vender pcs m";gD[m
电脑 A 1 !S:@x.n@iR
电脑 A 1 IFY!3^;zO
光盘 B 2 K"1J1>CHQ
光盘 A 2 kD>vQ?
手机 B 3 [wR8q,2
手机 C 3 >W<5$ .G
23、说明:初始化表table1 J0 P
TRUNCATE TABLE table1 PG!vn@b6
24、说明:选择从10到15的记录 _X[c19q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc J\V(MN,
m+g>s&1H
9E^piLA
Q?@G>uz
三、技巧 2?j1~ ]DvZ
1、1=1,1=2的使用,在SQL语句组合时用的较多 zvD5i,I
"where 1=1" 是表示选择全部 "where 1=2"全部不选, zYL^e @
如: <c#[.{A}s
if @strWhere !='' 9:>K!@
begin O^#u%/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere U ~m.I
end zMKL: Um"
else (a?Ip)`I
begin oB9m\o7$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 0=B5
=qyw
end gISs+g
我们可以直接写成 ${wE5^ky
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere MeX1y]<It
2、收缩数据库 qZh~Ay6I
--重建索引 [_d*J/ X
DBCC REINDEX GN0'-z6Uy
DBCC INDEXDEFRAG 5b,98Q
--收缩数据和日志 '_)tR;s
DBCC SHRINKDB c &HoS
DBCC SHRINKFILE qE}YVKV*
3、压缩数据库 L nGSYrx1
dbcc shrinkdatabase(dbname) 7W"menw
4、转移数据库给新用户以已存在用户权限 BP$#a
#
exec sp_change_users_login 'update_one','newname','oldname' U4gJ![>5j
go Y>~JI;Cu`
5、检查备份集 c29Z1Zs2)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' S<~nk-xr*h
6、修复数据库 / 5Loj&!=
ALTER DATABASE [dvbbs] SET SINGLE_USER 4&D="GA
GO @:B1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK z7C1&bGe
GO L ]c9
ALTER DATABASE [dvbbs] SET MULTI_USER x3|'jmg
GO DlI5} Jh
7、日志清除 mI#; pO2
SET NOCOUNT ON ]6 wi
DECLARE @LogicalFileName sysname, !`lqWO_/
:
@MaxMinutes INT, ;kBies>V
@NewSize INT `@7tWX0
USE tablename -- 要操作的数据库名 03@|dN
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t;Om9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Z >=Y
@NewSize = 1 -- 你想设定的日志文件的大小(M) Sj?sw]3
-- Setup / initialize AHJ;>"]
DECLARE @OriginalSize int Q%^bA,$&D
SELECT @OriginalSize = size 4a!7|}W
FROM sysfiles "M^W:4_
WHERE name = @LogicalFileName u7WM6X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + +_P
2S
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6/ipdi[
_
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' -^v}T/Kl#
FROM sysfiles Ir #V2]$
WHERE name = @LogicalFileName z D<9A6AB
CREATE TABLE DummyTrans `gN68:B
(DummyColumn char (8000) not null) N1~$ +
DECLARE @Counter INT, "|`9{/]
@StartTime DATETIME, X>7]g670@
@TruncLog VARCHAR(255) \*aLyyy3
SELECT @StartTime = GETDATE(), <|3v@
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' /g'-*:a
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <z2mNq
EXEC (@TruncLog) F*VMS
-- Wrap the log if necessary. vp-7>Wj
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired [oLQd-+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =hIT?Z6A
AND (@OriginalSize * 8 /1024) > @NewSize ^]&{"!
BEGIN -- Outer loop. I?Fa
SELECT @Counter = 0 +t4m\/y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) i0Q
_f!j
BEGIN -- update sA-W^*+
INSERT DummyTrans VALUES ('Fill Log') PRC)GP&q
DELETE DummyTrans /? 1Yf
SELECT @Counter = @Counter + 1 L^1q/4${
END z.&%>%TPP
EXEC (@TruncLog) N09+id g
END Mk/!,N<h#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + h./vTNMc
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )=nPM`Jn.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !r
obau7
FROM sysfiles /(ju
WHERE name = @LogicalFileName +WN>9V0H
DROP TABLE DummyTrans '.
Hp*9R
SET NOCOUNT OFF h!av)nhM
8、说明:更改某个表 oV>AFs6
exec sp_changeobjectowner 'tablename','dbo' zy6(S_j
9、存储更改全部表 a<jE25t
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |#:dC #
@OldOwner as NVARCHAR(128), IPi<sE
@NewOwner as NVARCHAR(128) GtJ*&=(
AS I@Z*Nu1L
DECLARE @Name as NVARCHAR(128) m_02"'
DECLARE @Owner as NVARCHAR(128) 0$Y 9>)O
DECLARE @OwnerName as NVARCHAR(128) }9udo,RWu
DECLARE curObject CURSOR FOR vLFaZ^(
select 'Name' = name, i2a"J&,6O
'Owner' = user_name(uid) RG
r'<o )
from sysobjects Po11EZa$a
where user_name(uid)=@OldOwner -s%-*K+,W
order by name GL =XiBt
OPEN curObject s8Ry}{
FETCH NEXT FROM curObject INTO @Name, @Owner V/9"Xmv75
WHILE(@@FETCH_STATUS=0) ro^6:w3O^
BEGIN "Xk%3\{P
if @Owner=@OldOwner +M
O5'z
begin J*~2:{=%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) gq_7_Y/
exec sp_changeobjectowner @OwnerName, @NewOwner >l< ~Z;
end d3=6MX[c
-- select @name,@NewOwner,@OldOwner UoMWn"ZE
FETCH NEXT FROM curObject INTO @Name, @Owner W;oU +z^t$
END n vpPmc
close curObject Jv^cOc
deallocate curObject G q:4rG|
GO ddq 1NW
10、SQL SERVER中直接循环写入数据 g;#KBxE
declare @i int j)tCr Py
set @i=1 JlDDM
%
while @i<30 >+jbMAYSq
begin acYoOW1G
insert into test (userid) values(@i) +V);'"L
set @i=@i+1 U]! .~ji3
end "ex~LB
小记存储过程中经常用到的本周,本月,本年函数 :7Z\3_D/
Dateadd(wk,datediff(wk,0,getdate()),-1) opcR~tg@r
Dateadd(wk,datediff(wk,0,getdate()),6) DPS1GO*
Dateadd(mm,datediff(mm,0,getdate()),0) J={OOj
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0I>?_?~l6
Dateadd(yy,datediff(yy,0,getdate()),0) kV:FJx0xP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) yEpN,A
上面的SQL代码只是一个时间段 $mI:Im`s
Dateadd(wk,datediff(wk,0,getdate()),-1) ?F87C[o
Dateadd(wk,datediff(wk,0,getdate()),6) Y =g>r]2
就是表示本周时间段. E/8u'
下面的SQL的条件部分,就是查询时间段在本周范围内的: }]g95xT
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) q?Ku}eID3
而在存储过程中 o(d_uJOB
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +)JNFy-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) aFr!PQp4{