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。 ]Qh[%GD
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一、基础 u<x[5xH+
1、说明:创建数据库 ex{)mE4Cd
CREATE DATABASE database-name Fka1]|j9
2、说明:删除数据库 k>7gy?Y!K<
drop database dbname u}^a^B$
3、说明:备份sql server hkkF1
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--- 创建 备份数据的 device o7m99(
USE master 7ZL,p:f
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Q S5dP
--- 开始 备份 P)a("XnJ`
BACKUP DATABASE pubs TO testBack <WO&$&
4、说明:创建新表 ?a*fy}A|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) MX"A@p~H
根据已有的表创建新表: cb\jrbj6
A:create table tab_new like tab_old (使用旧表创建新表) ^-
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B:create table tab_new as select col1,col2... from tab_old definition only =PI^X\if88
5、说明:删除新表 Uf=vs(
drop table tabname 3| GNi~
6、说明:增加一个列 ,w,ENU0~f
Alter table tabname add column col type ^qE<yn
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。 #(m`2Z`H
7、说明:添加主键: Alter table tabname add primary key(col) [lmHXf@1C
说明:删除主键: Alter table tabname drop primary key(col) vx({N?
8、说明:创建索引:create [unique] index idxname on tabname(col....) d4b 9rtM
删除索引:drop index idxname #9URVq,
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement MtMvpHk
删除视图:drop view viewname xC=
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10、说明:几个简单的基本的sql语句 Y{+zg9L*
选择:select * from table1 where 范围 7qCJ]%)b6
插入:insert into table1(field1,field2) values(value1,value2) !#}v:~[A
删除:delete from table1 where 范围 1EKcD^U,
更新:update table1 set field1=value1 where 范围 aeN}hG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9:bh3@r/
排序:select * from table1 order by field1,field2 [desc] nF|#@O`1
总数:select count as totalcount from table1 #j(q/
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求和:select sum(field1) as sumvalue from table1 tI/mE[W
平均:select avg(field1) as avgvalue from table1 x.j Yip
最大:select max(field1) as maxvalue from table1 K0d-MC
最小:select min(field1) as minvalue from table1 9^6|ta0;0
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11、说明:几个高级查询运算词 o[5=S,'
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A: UNION 运算符 !=8L.^5c
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。 V+4k!
B: EXCEPT 运算符 }qgqb
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。 L8,H9T#e
C: INTERSECT 运算符 U08<V:~
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。 9}K(Q=
注:使用运算词的几个查询结果行必须是一致的。 xiOv$.@q
12、说明:使用外连接 |G`4"``]k
A、left outer join: *7:u-}c!
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。 [TiTff&LV
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 w>H%[\Qs
B:right outer join: /K2.V@T
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。 ;o~+2Fir
C:full outer join: ~frPV8^DP
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。 `dG.L
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二、提升 .ruz l(6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) rw}5nv
法一:select * into b from a where 1<>1 qv
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法二:select top 0 * into b from a rR),~ @]sL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) eR#gG^o8
insert into b(a, b, c) select d,e,f from b; N\CEocU
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) f)u*Q!BDD
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 %x cM_|AyR
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. zm;*:]S
4、说明:子查询(表名1:a 表名2:b)
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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) (Fbm9(q$d
5、说明:显示文章、提交人和最后回复时间 } K+Q9<~u
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [9YlLL@
6、说明:外连接查询(表名1:a 表名2:b) E :'
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c dy8In%
7、说明:在线视图查询(表名1:a ) L.I}-n
select * from (SELECT a,b,c FROM a) T where t.a > 1; 34++Rr [G
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 Mc#O+'](f
select * from table1 where time between time1 and time2 vV:MS O'r
select a,b,c, from table1 where a not between 数值1 and 数值2 WwCK K
9、说明:in 的使用方法 LX(iuf+l
select * from table1 where a [not] in ('值1','值2','值4','值6') 4z-,M7iP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @'F8 |I 6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Oo3qiw
11、说明:四表联查问题: `a/PIc"
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 ..... <'o 'H
12、说明:日程安排提前五分钟提醒 %z!d4J75
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 5tgILxSK
13、说明:一条sql 语句搞定数据库分页 x3Dg%=R
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 }v'PY/d.
14、说明:前10条记录 a@S4IoBg%
select top 10 * form table1 where 范围 #(26t _a
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.) ?hry=I(7r
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) k^'d@1z;C
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 gN!E*@7
(select a from tableA ) except (select a from tableB) except (select a from tableC) :#Ex3H7
17、说明:随机取出10条数据 @kCD.
select top 10 * from tablename order by newid() ]"2 v7)e
18、说明:随机选择记录 E{+c*sz
select newid() 98b9%Z'2f
19、说明:删除重复记录 Z+`{JE#
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ZB_16&2Ow
20、说明:列出数据库里所有的表名 **w*hd]
select name from sysobjects where type='U' W O+?gu
21、说明:列出表里的所有的 #<WyId(
select name from syscolumns where id=object_id('TableName') "M5ro$qZ}
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。 @3expC
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 o?Tp=Ge
显示结果: -UD~>s
type vender pcs JQbMw>Y
电脑 A 1 bHWvKv+
电脑 A 1 xj00eL
光盘 B 2 &=6cz$]z
光盘 A 2 3q.[-.q
手机 B 3 _?(hWC"0
手机 C 3 }Nd`;d
23、说明:初始化表table1 Q
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TRUNCATE TABLE table1 n[MIa]dK
24、说明:选择从10到15的记录 o,''f_tRQ|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc $jm>tW&;
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三、技巧 ad3z]dUZ9
1、1=1,1=2的使用,在SQL语句组合时用的较多 q$u\
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, beHCEwh
如: G(|(y=ck
if @strWhere !='' EkB6- nz
begin `S/1U87
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere eM1;Nl
end ncw?;
else I$6
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begin a m k42
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ubN"(F:!-S
end SU#P.y18%
我们可以直接写成 <
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .^`a6>EQ)|
2、收缩数据库 ,d [b"]Zy
--重建索引 T>uWf#&pjs
DBCC REINDEX 7p>-oR"
DBCC INDEXDEFRAG %6c*dy
--收缩数据和日志 W|-N>,G
DBCC SHRINKDB )r6SGlE[Y
DBCC SHRINKFILE {, *Y
3、压缩数据库 p`l[cVQ<
dbcc shrinkdatabase(dbname) XdIVMXLL\
4、转移数据库给新用户以已存在用户权限 ^s(X VVA
exec sp_change_users_login 'update_one','newname','oldname' B 1ZHV^
go 4M<JfD
5、检查备份集 m|cWX"#g
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b\|p
6、修复数据库 "/K&qj
ALTER DATABASE [dvbbs] SET SINGLE_USER w<F;&';@h
GO )zLS,/pk^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK f w>Gx9
GO M_.,c Vk
ALTER DATABASE [dvbbs] SET MULTI_USER }$k`[ivBx(
GO eze(>0\f
7、日志清除 fe9& V2Uu
SET NOCOUNT ON t1{%FJ0F
DECLARE @LogicalFileName sysname, Qpv}N*v^
@MaxMinutes INT, f$S
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@NewSize INT +8vzkfr3It
USE tablename -- 要操作的数据库名 7Ae,|k
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 g$-D?~(Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =*>4Gh
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@NewSize = 1 -- 你想设定的日志文件的大小(M) F6GZZKj
-- Setup / initialize m[Ac'la
DECLARE @OriginalSize int !wb~A0m
SELECT @OriginalSize = size xdBZ^Q
FROM sysfiles 5bznM[%xO
WHERE name = @LogicalFileName Gv+Tg/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?VN]0{JSp
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (#l_YI
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' G$kwc
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FROM sysfiles NUNn[c
WHERE name = @LogicalFileName UE#Ni 5
CREATE TABLE DummyTrans aaD$'Y,<>B
(DummyColumn char (8000) not null) JQh s=Xg
DECLARE @Counter INT, Jx
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@StartTime DATETIME, ):\{n8~
@TruncLog VARCHAR(255) RW PdS
SELECT @StartTime = GETDATE(), )w
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,vdP
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) s$\8)V52
EXEC (@TruncLog) B[_b J
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-- Wrap the log if necessary. >0+|0ba
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired v7OV;ea$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) .fh?=B[o#
AND (@OriginalSize * 8 /1024) > @NewSize M^JZ]W(
BEGIN -- Outer loop. dVGUhXN6
SELECT @Counter = 0 *=If1qZs
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) sriq(A
BEGIN -- update nh&<fnh
INSERT DummyTrans VALUES ('Fill Log') >dm._*M
DELETE DummyTrans '%RK KA
SELECT @Counter = @Counter + 1 <VxpMF
END MJ/%$
EXEC (@TruncLog) _NqT8C4C
END *_K-T#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + GuY5 %wr
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <w2NJ~M^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6.7Kp
FROM sysfiles |{LaZXU &
WHERE name = @LogicalFileName XM@i|AK
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DROP TABLE DummyTrans P$
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SET NOCOUNT OFF 9-iB?a7{.
8、说明:更改某个表 E!~2\qKT
exec sp_changeobjectowner 'tablename','dbo' &b6@_C9
9、存储更改全部表 I\%Lb
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch >h( rd1
@OldOwner as NVARCHAR(128), `FB?cPR
@NewOwner as NVARCHAR(128) hSKH#NS
AS N u2]~W&
DECLARE @Name as NVARCHAR(128) #!&R7/
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DECLARE @Owner as NVARCHAR(128) |QTqa~~B
DECLARE @OwnerName as NVARCHAR(128) c@#zjJhW]
DECLARE curObject CURSOR FOR 0#{]!>R
select 'Name' = name, 7>@/*S{X
'Owner' = user_name(uid) N3c)ce7[
from sysobjects }=m?gF%3
where user_name(uid)=@OldOwner jMWwu+w
order by name =yhfL2`aw
OPEN curObject bnY8.Lpf|
FETCH NEXT FROM curObject INTO @Name, @Owner 4-rI4A<
WHILE(@@FETCH_STATUS=0) jLS]^|
BEGIN {ro!OuA
if @Owner=@OldOwner 7`<? fO
begin X6*y/KGN
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &r5%WRzpYT
exec sp_changeobjectowner @OwnerName, @NewOwner mL5f_Fb+
end wR+`("2{r
-- select @name,@NewOwner,@OldOwner PyxN _agf
FETCH NEXT FROM curObject INTO @Name, @Owner $5CY<,f
END [K@!JY
close curObject ~)IJE+e>}
deallocate curObject
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GO "v(]"L
10、SQL SERVER中直接循环写入数据 `/ReJj&~
declare @i int uWtS83i
set @i=1 2pNJWYW"
while @i<30 "_@+/Iy.
begin _"bvT?|
insert into test (userid) values(@i) $<%
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set @i=@i+1 -t'oW*kdL
end vk+%#w
小记存储过程中经常用到的本周,本月,本年函数 ZjW| qb
Dateadd(wk,datediff(wk,0,getdate()),-1) !enz05VW6.
Dateadd(wk,datediff(wk,0,getdate()),6) EjE`S_i=
Dateadd(mm,datediff(mm,0,getdate()),0) XTaWd0Y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) RW[<e
Dateadd(yy,datediff(yy,0,getdate()),0) %vYlu%c<
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #&KE_n
上面的SQL代码只是一个时间段 )mVYqlU"
Dateadd(wk,datediff(wk,0,getdate()),-1) >t2)Z|1
Dateadd(wk,datediff(wk,0,getdate()),6) rWpfAE)!
就是表示本周时间段. mf[79:90^
下面的SQL的条件部分,就是查询时间段在本周范围内的: o?
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9}$dwl(
而在存储过程中 D c.W vUM
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) j=% -b]
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 3Il/3\