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。 ]Kp -2KW
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一、基础 cW\Y1=Gv|
1、说明:创建数据库 q|N4d9/b
CREATE DATABASE database-name u#v];6N
2、说明:删除数据库 S+//g+e|f
drop database dbname 9c=`Q5
3、说明:备份sql server 2"L a}Vx2
--- 创建 备份数据的 device Mg=R**s1x%
USE master /3CdP'c
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 6ragRS/'x
--- 开始 备份 5:X^Q.f;
BACKUP DATABASE pubs TO testBack y'U-y"7y
4、说明:创建新表 IyGW>g6_.
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 84M*)cKR~
根据已有的表创建新表: oD~q/04!
A:create table tab_new like tab_old (使用旧表创建新表) $1;@@LSw
B:create table tab_new as select col1,col2... from tab_old definition only 9Gk#2
5、说明:删除新表 -v62 s
drop table tabname '7>Yrzq
6、说明:增加一个列 OiMr,
Alter table tabname add column col type zr[|~-
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 DO9_o9'
7、说明:添加主键: Alter table tabname add primary key(col) |bv7N@?e
说明:删除主键: Alter table tabname drop primary key(col) \-R\xL
8、说明:创建索引:create [unique] index idxname on tabname(col....) Z6_E/S
删除索引:drop index idxname EMMp4KKOx+
注:索引是不可更改的,想更改必须删除重新建。 CGJ>j}C
9、说明:创建视图:create view viewname as select statement Tlz~o[`&
删除视图:drop view viewname r>x>aJ
10、说明:几个简单的基本的sql语句 be:=-B7!
选择:select * from table1 where 范围 )dZ1$MC[
插入:insert into table1(field1,field2) values(value1,value2) 3C(V<R?
删除:delete from table1 where 范围 jinXK
更新:update table1 set field1=value1 where 范围 .+dego:
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =z
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排序:select * from table1 order by field1,field2 [desc] Q@? {|7:
总数:select count as totalcount from table1 #tlhH\Pr[
求和:select sum(field1) as sumvalue from table1 q;H5S<]/
平均:select avg(field1) as avgvalue from table1 }X^CH2,R
最大:select max(field1) as maxvalue from table1 O(YvE
最小:select min(field1) as minvalue from table1 s!\Gi5b
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11、说明:几个高级查询运算词 3pI)
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A: UNION 运算符 "c0Nv8_G
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。 +}.S:w_xQ
B: EXCEPT 运算符 [p&2k&.XYe
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。 PBp+(o-
C: INTERSECT 运算符 _cD-E.E%
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。 #i}:CI>2
注:使用运算词的几个查询结果行必须是一致的。 OA{PKC
12、说明:使用外连接 d}(b!q9
A、left outer join: fGMuml?[ e
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。 `ls^fnJTpf
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 )b;}]C
B:right outer join: so@wUxF
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。 /H<tv5mXJ
C:full outer join: ps@{1Rn1
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。 -%6Y&_5VK
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二、提升 W``
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) /D
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法一:select * into b from a where 1<>1 } {<L<
法二:select top 0 * into b from a `*HM5 1U
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) (`FY{]Wz!
insert into b(a, b, c) select d,e,f from b; - {|
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) &Y|AX2KUC
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 i@hW" [A
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ?D S|vCae
4、说明:子查询(表名1:a 表名2:b) 6HR^q
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) 1i:Q
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5、说明:显示文章、提交人和最后回复时间 dEG1[QG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b TC^fyxq
6、说明:外连接查询(表名1:a 表名2:b) T +~
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mM)d`br
7、说明:在线视图查询(表名1:a ) YKG}4{T
select * from (SELECT a,b,c FROM a) T where t.a > 1; !S5_+.U#
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 R\,qL-Br
select * from table1 where time between time1 and time2 6T ,'Oz
select a,b,c, from table1 where a not between 数值1 and 数值2 w>uo-88
9、说明:in 的使用方法 ZRLS3*`
select * from table1 where a [not] in ('值1','值2','值4','值6') '?dT<w=Y&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 w@&(=C
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) AG(Gtvw
11、说明:四表联查问题: i+eDBg6
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 ..... 1h#UM6
12、说明:日程安排提前五分钟提醒 MgUjB~)Y
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "?#O*x
13、说明:一条sql 语句搞定数据库分页 Q9NKQuSu
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 1QJB4|5R#
14、说明:前10条记录 @86?!0bt
select top 10 * form table1 where 范围 Vf] ;hm
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.) g.d~`R@v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) qhqqCVrsW
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 %hH@< <b(s
(select a from tableA ) except (select a from tableB) except (select a from tableC) $V2.@X
17、说明:随机取出10条数据 h;S?
select top 10 * from tablename order by newid() l fJ
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18、说明:随机选择记录 BhCOT+i;c
select newid() Y[Kpd[)[v
19、说明:删除重复记录 ]d -U
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) G
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20、说明:列出数据库里所有的表名 `as6IMqJD
select name from sysobjects where type='U' Z}s56{!.
21、说明:列出表里的所有的 %:/?eZ
select name from syscolumns where id=object_id('TableName') 1@{qPmf^
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!@`tR-
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 4+'d">+|
显示结果: u:GDM
type vender pcs 6R+EG{`
电脑 A 1 /w2jlu}yt
电脑 A 1 2<33BBlWA
光盘 B 2 WDq~mi
光盘 A 2 QTT2P(Pz
手机 B 3 $61j_;WF`
手机 C 3 A~%h*nZc%I
23、说明:初始化表table1 m.2=,,r<Fq
TRUNCATE TABLE table1 %Tm8sQ)1
24、说明:选择从10到15的记录 JPGEE1!B{b
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 1_0\_|
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三、技巧 :Wl`8p4]
1、1=1,1=2的使用,在SQL语句组合时用的较多 rw]7Lr_>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;/=6~%
如: HlC[Nu^6U
if @strWhere !='' 6UnWtLE
begin m(eR Wx&pZ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Bl!R
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end DfV'1s4y
else >{@:p`*
begin Ab/KVB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ZtH{2j0
end `d6,]'
我们可以直接写成 )9'Zb`n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PWbi`qF)r
2、收缩数据库 N,~"8YSo
--重建索引 %"g; K
DBCC REINDEX 3?:?dy(3z
DBCC INDEXDEFRAG z((9vi W
--收缩数据和日志 )h,-zAnZ
DBCC SHRINKDB T f;:C]
DBCC SHRINKFILE 3}25=%;[
3、压缩数据库 sTChbks
dbcc shrinkdatabase(dbname) \>nY%*
4、转移数据库给新用户以已存在用户权限 yi@mf$A|
exec sp_change_users_login 'update_one','newname','oldname' TDR2){I
go (Q~(t
5、检查备份集 6*tbil_G+
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' >a$b4
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6、修复数据库 ,J ZM%f
ALTER DATABASE [dvbbs] SET SINGLE_USER i$W
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GO KmE<+/x~?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o]O
GO sm96Ye{O{
ALTER DATABASE [dvbbs] SET MULTI_USER 1G62Qu$O
GO 4oywP^I
7、日志清除 VH2/
SET NOCOUNT ON ^dCSk==
DECLARE @LogicalFileName sysname, m0_B[dw
@MaxMinutes INT, FErKr)
@NewSize INT 3E]IEf
USE tablename -- 要操作的数据库名 $G@^!(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9G"-~C"e3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. z1`z
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@NewSize = 1 -- 你想设定的日志文件的大小(M) )*I%rN8b
-- Setup / initialize f+W8Gszi
DECLARE @OriginalSize int ruTj#tWSo
SELECT @OriginalSize = size #uillSV
FROM sysfiles DY6ra% T
WHERE name = @LogicalFileName PHHX)xK
SELECT 'Original Size of ' + db_name() + ' LOG is ' + r,-9]?i
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + gt{$G|bi
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 'W]oQLD^R
FROM sysfiles -e(,>9Q
WHERE name = @LogicalFileName /!HFi>
CREATE TABLE DummyTrans 4,P!D3SH
(DummyColumn char (8000) not null) BLQD=?Q
DECLARE @Counter INT, h(H b+7g
@StartTime DATETIME, FST}:*dOe5
@TruncLog VARCHAR(255) 9a;8^?Ld%S
SELECT @StartTime = GETDATE(), OJ2I (8P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' bJ6@
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;$>wuc'L
EXEC (@TruncLog) ;_<K>r*
-- Wrap the log if necessary. Imm|5-qJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired [[8.Xb
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) sksop4gu5
AND (@OriginalSize * 8 /1024) > @NewSize elzKtVw
BEGIN -- Outer loop. `UH 1B/
SELECT @Counter = 0 X"p p l7o
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) P|{Et=R`1
BEGIN -- update `p{,C`g,R
INSERT DummyTrans VALUES ('Fill Log') GYM6 `
DELETE DummyTrans >h<bYk "9Q
SELECT @Counter = @Counter + 1 Isna
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END z3>oUq{
EXEC (@TruncLog) /'g"Ys?3
END UZ}>@0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + qc6eqE
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + EU@XLm6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 2W]y9)<c
FROM sysfiles qtLXdSc
WHERE name = @LogicalFileName vspub^;5\
DROP TABLE DummyTrans V-
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SET NOCOUNT OFF [osm\w49
8、说明:更改某个表 TDnbX_xC<
exec sp_changeobjectowner 'tablename','dbo' J 8""}7D
9、存储更改全部表 KIfR4,=Q|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch [H8QxJk
@OldOwner as NVARCHAR(128), I}{Xv#@o
@NewOwner as NVARCHAR(128) >iIUS
AS ":upo/xN
DECLARE @Name as NVARCHAR(128) L.M|o
DECLARE @Owner as NVARCHAR(128) BL Q&VI4
DECLARE @OwnerName as NVARCHAR(128) YMEI
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DECLARE curObject CURSOR FOR ,H+LE$=
select 'Name' = name, Z6XP ..
'Owner' = user_name(uid) )ls<"WTC.
from sysobjects v'zj<|2
where user_name(uid)=@OldOwner 2E
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order by name KB^i=+xr
OPEN curObject |L"!^Y#=D
FETCH NEXT FROM curObject INTO @Name, @Owner byUz
WHILE(@@FETCH_STATUS=0) [6Nw)r(a(
BEGIN m&X6a C'[
if @Owner=@OldOwner oI6o$C
begin 3x{2Dh i
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !j|93*
exec sp_changeobjectowner @OwnerName, @NewOwner |+0XO?,sZ
end F&I ;E i
-- select @name,@NewOwner,@OldOwner .0zNt
FETCH NEXT FROM curObject INTO @Name, @Owner sXaIQhZ
END %:
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close curObject Oor&1
deallocate curObject =z$XqT.'
GO fsDwfwil*
10、SQL SERVER中直接循环写入数据 >IzUn: 0F
declare @i int ugI9rxT]Kv
set @i=1 Xu8_ <%
while @i<30 h&4f9HhS=
begin }7H8Y}m
insert into test (userid) values(@i) fQB>0RR2
set @i=@i+1 bkgJz+u
end P5*~Wi`
小记存储过程中经常用到的本周,本月,本年函数 MXj7Z3
Dateadd(wk,datediff(wk,0,getdate()),-1) }`,}e 259
Dateadd(wk,datediff(wk,0,getdate()),6) oIP<7gz
Dateadd(mm,datediff(mm,0,getdate()),0) Lz9t9AoB
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) utvZ<zz`
Dateadd(yy,datediff(yy,0,getdate()),0) NHCdf*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -OS&(7
上面的SQL代码只是一个时间段 u0(PWCi2
Dateadd(wk,datediff(wk,0,getdate()),-1) '`*{ig
Dateadd(wk,datediff(wk,0,getdate()),6) Pkbx/\
就是表示本周时间段. F9Ag687w
下面的SQL的条件部分,就是查询时间段在本周范围内的: 9w=GB?/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) R""P01IZH
而在存储过程中 V~uH)IMkh7
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]$>O--
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) x{X(Y]*1S