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。 7DJEx~"!2-
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一、基础 Q38+`EhLA
1、说明:创建数据库 SG)Fk *1
CREATE DATABASE database-name ~^1y(-cw
2、说明:删除数据库 e'.BTt58Y
drop database dbname `/PBZnj
3、说明:备份sql server G0UaE1n
--- 创建 备份数据的 device %6320 x
USE master lH4Nbluc^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]ub"OsXC
--- 开始 备份 -U /)y:k!%
BACKUP DATABASE pubs TO testBack ,2fi`9=\
4、说明:创建新表 CW+kKN
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) .jCGtR )%
根据已有的表创建新表: _d@YLd78P
A:create table tab_new like tab_old (使用旧表创建新表) Wlhh0uy
B:create table tab_new as select col1,col2... from tab_old definition only V1]GOmXz
5、说明:删除新表 >J7slDRo
drop table tabname <-v
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6、说明:增加一个列 eP @#I^_
Alter table tabname add column col type rE+B}O
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。 [[ie
7、说明:添加主键: Alter table tabname add primary key(col) uCDe>Q4@/
说明:删除主键: Alter table tabname drop primary key(col) 8gP1]xD
8、说明:创建索引:create [unique] index idxname on tabname(col....) '5BD%#[
删除索引:drop index idxname @:}c(j
注:索引是不可更改的,想更改必须删除重新建。 ?XHQdN3e
9、说明:创建视图:create view viewname as select statement Fa%1]R
删除视图:drop view viewname ]@#9B>v=
10、说明:几个简单的基本的sql语句 kkq1:\pZ]a
选择:select * from table1 where 范围 >9{?]x
插入:insert into table1(field1,field2) values(value1,value2) e'K~WNT
删除:delete from table1 where 范围 g{Hgs
更新:update table1 set field1=value1 where 范围 N(7 XILC
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "U}kp#)
排序:select * from table1 order by field1,field2 [desc] ^O_Z5NbC3
总数:select count as totalcount from table1 lp
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求和:select sum(field1) as sumvalue from table1 3=.YQE0!dx
平均:select avg(field1) as avgvalue from table1 u"HGT=Nl
最大:select max(field1) as maxvalue from table1 L!cOg8Z
最小:select min(field1) as minvalue from table1 -!PJHCLd
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11、说明:几个高级查询运算词 eN=jWUoCh
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A: UNION 运算符 }p~2lOI
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。 "#~>q(4^
B: EXCEPT 运算符 "W7|Xp
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。 UGO#o`.G}
C: INTERSECT 运算符 .TGw+E1k
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。 <8:h%%$?
注:使用运算词的几个查询结果行必须是一致的。 aD: #AmbJ
12、说明:使用外连接 QF>T)1&J[7
A、left outer join: >jI.$%L$
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。 O&l4/RtQ\)
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 sSW'SE?,<
B:right outer join: sycAAmH<
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。 %>m.Z#R(
C:full outer join: pQiC#4b
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。 q_b!+Y
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二、提升 ;XN|dq
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o Xm
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法一:select * into b from a where 1<>1 QC+
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法二:select top 0 * into b from a 0>{ ]*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Jy(G
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insert into b(a, b, c) select d,e,f from b; r)^sHpK:`
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) <X)\P}"L4
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ? "I %K%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4LTm&+(5
4、说明:子查询(表名1:a 表名2:b) ~IhM(Q*mO!
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) _*o<<C\E
5、说明:显示文章、提交人和最后回复时间 yT7$6x
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0/GBs~P
6、说明:外连接查询(表名1:a 表名2:b)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ray3gM%JLj
7、说明:在线视图查询(表名1:a ) wK(]E%\
select * from (SELECT a,b,c FROM a) T where t.a > 1; pAy4%|(
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 '[#y|
select * from table1 where time between time1 and time2 h3@tZL#g
select a,b,c, from table1 where a not between 数值1 and 数值2 s47R,K$
9、说明:in 的使用方法 jqaX|)8|$
select * from table1 where a [not] in ('值1','值2','值4','值6') gzs\C{4D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 _LaG%* R6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7"(Zpu
11、说明:四表联查问题: ~(R=3
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 ..... a3yNd
12、说明:日程安排提前五分钟提醒 -.h)CM@L
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Jpapl%7v
13、说明:一条sql 语句搞定数据库分页 KL_/f
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 A)U"F&tvm
14、说明:前10条记录 Rt#QW*h\|i
select top 10 * form table1 where 范围 GB$`b'x@S
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) tW UI?\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) lUu0AZQmG
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 u}%OC43
(select a from tableA ) except (select a from tableB) except (select a from tableC) B'yjMY![
17、说明:随机取出10条数据 bWo
select top 10 * from tablename order by newid() :BPgDLL,
18、说明:随机选择记录 &Sd5]r@+
select newid() ?,pwYT0g
19、说明:删除重复记录 FOG{dio
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) A$@;Q5/2
20、说明:列出数据库里所有的表名 ({E,}x
select name from sysobjects where type='U' g7zl5^o3j
21、说明:列出表里的所有的 3'uXU<W!
select name from syscolumns where id=object_id('TableName') Xe_ <]|
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。 !{-W%=Kf
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 }h^
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显示结果: xrg"/?84
type vender pcs FDl/7P`b(
电脑 A 1 @6"MhF
电脑 A 1 ?,$:~O*w
光盘 B 2 N?qETp -:
光盘 A 2 rnK]3Ust
手机 B 3 0T`Qoo>u
手机 C 3 *ak0(yLn)
23、说明:初始化表table1 M+&~sX*a
TRUNCATE TABLE table1 O!"K'Bm
24、说明:选择从10到15的记录 'UX^]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc D|zuj]
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三、技巧 ?6_]^:s
1、1=1,1=2的使用,在SQL语句组合时用的较多 !}6'vq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, V(TtOuv
如: G u`xJ
if @strWhere !='' "bej#'M#
begin kqeEm{I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 11l=zv
end :P-H8*n""
else 5X^\AW
begin x@Gg fH<l
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8U@f/P
end Vs"b
我们可以直接写成 ;}Jv4Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +k6`
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2、收缩数据库 tpSgbGzp
--重建索引 CNRSc4Le
DBCC REINDEX {mU%.5
DBCC INDEXDEFRAG %i?
--收缩数据和日志 HW[&q
DBCC SHRINKDB .M:&Aj)x16
DBCC SHRINKFILE +j: &_
3、压缩数据库 _EMXx4J
dbcc shrinkdatabase(dbname) le^Fik
4、转移数据库给新用户以已存在用户权限 ]ttF''lH
exec sp_change_users_login 'update_one','newname','oldname' <7y/)b@
go \Hb!<mrp
5、检查备份集 ;\th.!'rn
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' YAXd
6、修复数据库 \L>XF'o
ALTER DATABASE [dvbbs] SET SINGLE_USER |~A*?6:@
GO % (h6m${j
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 3sV$#l P
GO L/fXP@u
ALTER DATABASE [dvbbs] SET MULTI_USER 1R_@C.I
GO yPmo1|'X>d
7、日志清除 \:h7,[e
SET NOCOUNT ON npeL1zO-$
DECLARE @LogicalFileName sysname, t!wbT79/
@MaxMinutes INT, G>pedE\
@NewSize INT 1o5kP,)
USE tablename -- 要操作的数据库名 f IV"U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &DGqY5=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #TUm&2 +V
@NewSize = 1 -- 你想设定的日志文件的大小(M) \@PMj"p|:
-- Setup / initialize Zs^zD;zU
DECLARE @OriginalSize int pej-W/R&
SELECT @OriginalSize = size VP< zOk7
FROM sysfiles ~98q1HgS]D
WHERE name = @LogicalFileName >W+,(kAS
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !_Y%+Rkp0
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' TS#1+f]9J<
FROM sysfiles )[Rwc#PA;
WHERE name = @LogicalFileName 2G|}ENC
CREATE TABLE DummyTrans euY+jc%
(DummyColumn char (8000) not null) 3K(/=
DECLARE @Counter INT, 6&+dpr&c~=
@StartTime DATETIME, 5<X"+`=9
@TruncLog VARCHAR(255) )j]f
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SELECT @StartTime = GETDATE(), ,h5 FX^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1V5N)ty
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $lB!Q8a$
EXEC (@TruncLog) FM3.z)>
-- Wrap the log if necessary. 4Tuh]5
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *#p}FB2H#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =Q;dYx%I5
AND (@OriginalSize * 8 /1024) > @NewSize =WF@S1
BEGIN -- Outer loop. W SvhC
SELECT @Counter = 0 c&#Q`m
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) r
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BEGIN -- update Q_/UC#I8
INSERT DummyTrans VALUES ('Fill Log') ^Gbcs
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DELETE DummyTrans Hj-n
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SELECT @Counter = @Counter + 1 %N\45nYU:
END S41S+#7t*
EXEC (@TruncLog) (CDh,ZN;|
END iMM9a;G+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + r
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + r"L:Mu
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' *` -
FROM sysfiles %7[d5[U~ZA
WHERE name = @LogicalFileName `j2|aX
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DROP TABLE DummyTrans v*y,PY1*
SET NOCOUNT OFF M;g"rpM
8、说明:更改某个表 , Sf:R4=
exec sp_changeobjectowner 'tablename','dbo' Ayw {I#"
9、存储更改全部表 4d`f?8vS
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |em_l$oGc
@OldOwner as NVARCHAR(128), &4t=Y`]SL
@NewOwner as NVARCHAR(128) zcV~)go6
AS 4fL>Ou[YuX
DECLARE @Name as NVARCHAR(128) w$qdV,s 7
DECLARE @Owner as NVARCHAR(128) dpdp0
DECLARE @OwnerName as NVARCHAR(128) ]7,0}q.
DECLARE curObject CURSOR FOR 9D5v0Qi
select 'Name' = name, fob.?ID-;
'Owner' = user_name(uid) 06af{FXsGb
from sysobjects %
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where user_name(uid)=@OldOwner BC%V<6JBu(
order by name :y~l?0b&8
OPEN curObject _P_R`A)"
FETCH NEXT FROM curObject INTO @Name, @Owner ~c,+)69"T
WHILE(@@FETCH_STATUS=0) 0;5qo~1
BEGIN Y4Jaw2b
if @Owner=@OldOwner |@D%y&
begin (Kkqyrb
set @OwnerName = @OldOwner + '.' + rtrim(@Name) + VhD]!
exec sp_changeobjectowner @OwnerName, @NewOwner GQ9H>Ssz
end 0$R}_Ok
-- select @name,@NewOwner,@OldOwner @oRo6Y<-
FETCH NEXT FROM curObject INTO @Name, @Owner F{17K$y
END 4n\O6$&.x
close curObject &K"qnng/y
deallocate curObject Cm6%wAzC
GO l\bgp3.+
10、SQL SERVER中直接循环写入数据 I(Q3YDdb
declare @i int F`f8q\Fc
set @i=1 r[&/*~xL
while @i<30 H3|x
begin V(!-xu1,
insert into test (userid) values(@i) T;Ra/H
set @i=@i+1 ?h-:,icR
end @3Mp>u/
小记存储过程中经常用到的本周,本月,本年函数 eBlB0P
Dateadd(wk,datediff(wk,0,getdate()),-1) Qvhy9Cr;
Dateadd(wk,datediff(wk,0,getdate()),6) X./7b{Pax
Dateadd(mm,datediff(mm,0,getdate()),0) d/I*$UC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 3B ;aoejHm
Dateadd(yy,datediff(yy,0,getdate()),0) \yo)oIi[p
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :8Ql(I
上面的SQL代码只是一个时间段 D]5cijO6
Dateadd(wk,datediff(wk,0,getdate()),-1) 5PT*b}g@
Dateadd(wk,datediff(wk,0,getdate()),6) OO?BN!
就是表示本周时间段. } |? W
下面的SQL的条件部分,就是查询时间段在本周范围内的: kKNrCv@64d
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) iriF'(1
而在存储过程中 \QMRuR.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %1PNP<3r0
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <.c#l':