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。 zw\"!=r^
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一、基础 03$Ay_2
1、说明:创建数据库 [EB2o.EsO
CREATE DATABASE database-name B?#@<2*=L
2、说明:删除数据库 v@Otp
drop database dbname )K8JDP
3、说明:备份sql server ir \ d8.
--- 创建 备份数据的 device djZOx;/
USE master P)(Ly5$*
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' D;BFl(l
--- 开始 备份 kki]6_/n
BACKUP DATABASE pubs TO testBack CU lANd"
4、说明:创建新表 P@k
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) *Ty>-aS1
根据已有的表创建新表: :3Ty%W&&
A:create table tab_new like tab_old (使用旧表创建新表) {D1=TTr^
B:create table tab_new as select col1,col2... from tab_old definition only 7QQ3IepP
5、说明:删除新表 bnB}VRal
drop table tabname @B7;
6、说明:增加一个列 _ky!4^B
Alter table tabname add column col type 0kmVP~K
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。 &b"PjtU.X
7、说明:添加主键: Alter table tabname add primary key(col) /5U?4l(6[f
说明:删除主键: Alter table tabname drop primary key(col) /3FC@?l
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8、说明:创建索引:create [unique] index idxname on tabname(col....) T{?!sB3
删除索引:drop index idxname X k<X:,T
注:索引是不可更改的,想更改必须删除重新建。 sJ3HH0e
9、说明:创建视图:create view viewname as select statement _.?$~;7
删除视图:drop view viewname Q1buuF#CU&
10、说明:几个简单的基本的sql语句 B7?784{x,
选择:select * from table1 where 范围 V9B $_j4
插入:insert into table1(field1,field2) values(value1,value2) 6l:CDPhR
删除:delete from table1 where 范围 \DeZY97p%
更新:update table1 set field1=value1 where 范围 khjW9Aa8t
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! T(J&v|FK
排序:select * from table1 order by field1,field2 [desc] gbXzD`WQ
总数:select count as totalcount from table1 BCsW03sQ
求和:select sum(field1) as sumvalue from table1 #V4_. t#
平均:select avg(field1) as avgvalue from table1 &&_W,id`
最大:select max(field1) as maxvalue from table1 =qIJXV
最小:select min(field1) as minvalue from table1 A' dt
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11、说明:几个高级查询运算词 M~ynJ@q
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A: UNION 运算符 D'uzH|z8
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 sx`C<c~u
B: EXCEPT 运算符 4;w_o9o
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 L_ 8C=MS
C: INTERSECT 运算符 5#QB&A>
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 4V43(G
注:使用运算词的几个查询结果行必须是一致的。 #G)ZhgB^
12、说明:使用外连接 `S$BBF;
A、left outer join: 8I@=?
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。 'hU&$lgMF
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c a l#yc
B:right outer join: *(D_g!a
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 -PEpy3dMY
C:full outer join: 9)l[$X
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。 >qcir~ &
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二、提升 KZ/}Iy>As
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) T3'dfe U
法一:select * into b from a where 1<>1 A3Ltk 2<
法二:select top 0 * into b from a ``>WFLWTn
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) JK[7&C-O
insert into b(a, b, c) select d,e,f from b; t?YGGu^
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) olK%TM[Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /oe="/y6
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. b*?="%eE(
4、说明:子查询(表名1:a 表名2:b) sNS!/
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) '=%vf
5、说明:显示文章、提交人和最后回复时间 $Iqt
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b T][\wyLx1
6、说明:外连接查询(表名1:a 表名2:b) Q\ro )r
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 33"{"2==`
7、说明:在线视图查询(表名1:a ) 2&Wc4,O!i
select * from (SELECT a,b,c FROM a) T where t.a > 1; qI5/ME(}
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -!wm]kx
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select * from table1 where time between time1 and time2 {#>@h7
select a,b,c, from table1 where a not between 数值1 and 数值2 JMO"(?
9、说明:in 的使用方法 V,
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select * from table1 where a [not] in ('值1','值2','值4','值6') Z{u*vUC&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @kI^6(.
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Jw;J$
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11、说明:四表联查问题: i1|-
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 ..... ffuV$#
12、说明:日程安排提前五分钟提醒 h2h$UZIv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 V1#/+~
13、说明:一条sql 语句搞定数据库分页 t=A|
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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 Wc-P= J*m
14、说明:前10条记录 mIl^
select top 10 * form table1 where 范围 bLaD1rnGi
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.) l3l[jDa, 2
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q0ev*MS9Z
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 i aP+Vab
(select a from tableA ) except (select a from tableB) except (select a from tableC) %<I0-o
17、说明:随机取出10条数据 4y%N(^
select top 10 * from tablename order by newid() mxP{"6
18、说明:随机选择记录 vV"TTzs!
select newid() 2 B5kpmH:
19、说明:删除重复记录 @f{)]I +f
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [4t_ 83
20、说明:列出数据库里所有的表名 KWN0$*4
select name from sysobjects where type='U' w7w$z_P
21、说明:列出表里的所有的 I:AlM?
select name from syscolumns where id=object_id('TableName') NWX~@Rg
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。 BD,~M*%z
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 {7B$%G'
显示结果: Z*s/%4On
type vender pcs _3hCu/BV
电脑 A 1 kTs)u\r.
电脑 A 1 :~U1JAs$
光盘 B 2 .:_dS=ut
光盘 A 2 F;`of
手机 B 3 qXP)R/~OZ
手机 C 3 ,ulTZV
23、说明:初始化表table1 X o{Ce%L
TRUNCATE TABLE table1 q'q'v
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24、说明:选择从10到15的记录 %Ljc#AVg
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc CF =#?+x
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三、技巧 OuS{ve
1、1=1,1=2的使用,在SQL语句组合时用的较多 IExQ}I
"where 1=1" 是表示选择全部 "where 1=2"全部不选, l|j&w[c[Q0
如: L-G186B$r
if @strWhere !='' P{rJG
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begin LFV;Y.-(h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere HHa7Kh|-H
end +(UrqK4Av
else C=%go1! $
begin 8m-jU
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ruF+X)
end od?Q&'A
我们可以直接写成 lKH"PH7*_w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere u+th?KO`
2、收缩数据库 |WubIj*\{
--重建索引 "0zMx`Dh
DBCC REINDEX D.R5-
DBCC INDEXDEFRAG [9aaHf@'
--收缩数据和日志 /KlA7MH 6
DBCC SHRINKDB .- c3f1i
DBCC SHRINKFILE ,iiWVA"
3、压缩数据库 +S0A`rL
dbcc shrinkdatabase(dbname) x1mxM#ql
4、转移数据库给新用户以已存在用户权限 G}D?+MWY
exec sp_change_users_login 'update_one','newname','oldname' >D<nfG<s Z
go fB;'U
5、检查备份集 5
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' J6NQ5S\
6、修复数据库 >i@gR
ALTER DATABASE [dvbbs] SET SINGLE_USER k 2;m"F
GO Fk=_Q
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK e0>@Yp[Kd
GO ][wS}~):
ALTER DATABASE [dvbbs] SET MULTI_USER AVNB)K"
GO 2MB\!fh
7、日志清除 vk;>#yoox
SET NOCOUNT ON !Me%W3
DECLARE @LogicalFileName sysname, 3]xnKb|W
@MaxMinutes INT, +=u*!6S
@NewSize INT pPG!{:YT
USE tablename -- 要操作的数据库名 fBw+Y4nCO7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _[XEL+.
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d'Gv \i&e
@NewSize = 1 -- 你想设定的日志文件的大小(M) z?1GJ8
-- Setup / initialize |byB7f
DECLARE @OriginalSize int $_)YrqSo~
SELECT @OriginalSize = size If!0w
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FROM sysfiles >fs-_>1d
WHERE name = @LogicalFileName _mXq]r0
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \mWXr*;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + B;W=61d
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' e/@udau
FROM sysfiles Yn1 U@!
WHERE name = @LogicalFileName !j YV,:'
CREATE TABLE DummyTrans h`3;^T
(DummyColumn char (8000) not null) )-9|3`
DECLARE @Counter INT, uVOpg]8d
@StartTime DATETIME, ZpI _/
@TruncLog VARCHAR(255) TSHp.ABf
SELECT @StartTime = GETDATE(), ] ^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' D8[&}D4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) |nU:
EXEC (@TruncLog) GXJ3E"_.
-- Wrap the log if necessary. `Rj
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Qyd3e O_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) L[TL~@T
AND (@OriginalSize * 8 /1024) > @NewSize f()^^ +
BEGIN -- Outer loop. =7Tbu'O;
SELECT @Counter = 0 dVe3h.,[v
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) K7e<hdP_#
BEGIN -- update %qja:'k
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans o~es>;
SELECT @Counter = @Counter + 1 z{!wQ~
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END tEP^w
EXEC (@TruncLog) Kau*e8
END hh: )"<[
SELECT 'Final Size of ' + db_name() + ' LOG is ' + WxO*{`T!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
]
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Q&M(wnl5
FROM sysfiles /0SPRf}p
WHERE name = @LogicalFileName |U7{!yy%MF
DROP TABLE DummyTrans 3P-#NL
SET NOCOUNT OFF i1aS2gFi_
8、说明:更改某个表 %$sWNn
exec sp_changeobjectowner 'tablename','dbo' 3t%uUkXl
9、存储更改全部表 o2Pj|u*X
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *jA%.F
@OldOwner as NVARCHAR(128), Hyee#fB
@NewOwner as NVARCHAR(128) 1egryp
AS -P'>~W,~
DECLARE @Name as NVARCHAR(128) 39~fP)
DECLARE @Owner as NVARCHAR(128) ]]d@jj
DECLARE @OwnerName as NVARCHAR(128) {'r(P&
DECLARE curObject CURSOR FOR 8oA6'%.e
select 'Name' = name, WNL3+
'Owner' = user_name(uid) }[i35f[w
from sysobjects y)(SS8JR
where user_name(uid)=@OldOwner A 9tQb:
order by name \N"K^kR4
OPEN curObject rt~X(S
FETCH NEXT FROM curObject INTO @Name, @Owner pF"z)E|^
WHILE(@@FETCH_STATUS=0) by8d18:it
BEGIN xYwbbFGrG
if @Owner=@OldOwner )]qFI"B7
begin G9VzVx#T#
set @OwnerName = @OldOwner + '.' + rtrim(@Name) {bc<0
exec sp_changeobjectowner @OwnerName, @NewOwner .v;2Q7X
end h)A+5^:^
-- select @name,@NewOwner,@OldOwner }T(|\
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FETCH NEXT FROM curObject INTO @Name, @Owner 70KXBu<6
END {v]>sn;P1
close curObject tbOe,-U-@
deallocate curObject (!Ml2
GO P<2yCovn`
10、SQL SERVER中直接循环写入数据 xsAF<:S\
declare @i int 09x\i/nb
set @i=1 5l)p5Bb48c
while @i<30 ih~c(&n0
begin (G$m}ng
insert into test (userid) values(@i) 4r5,kOFWb
set @i=@i+1 z':>nw
end %o{vD&7\
小记存储过程中经常用到的本周,本月,本年函数 \
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Dateadd(wk,datediff(wk,0,getdate()),-1) 2]4R`[#
Dateadd(wk,datediff(wk,0,getdate()),6) Po^2+s(fY
Dateadd(mm,datediff(mm,0,getdate()),0) n\cP17dr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 88G[XkL$2
Dateadd(yy,datediff(yy,0,getdate()),0) 0s<o5`v
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \LM'KD pP_
上面的SQL代码只是一个时间段 4>5%SzZT\3
Dateadd(wk,datediff(wk,0,getdate()),-1) -,5g cD
Dateadd(wk,datediff(wk,0,getdate()),6) x$s #';*
就是表示本周时间段. _=}Y
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下面的SQL的条件部分,就是查询时间段在本周范围内的: H56e#:[$
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) qw_qGgbl
而在存储过程中 _n{N3da
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) j83p[qR7o
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1p8E!c{}j