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。 A:yHClmn
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一、基础 qv& Bai[
1、说明:创建数据库 :of(wZa3Q
CREATE DATABASE database-name 8Cs;.>75[
2、说明:删除数据库 w 5 yOSz
drop database dbname Z1#u&oX
3、说明:备份sql server X NgcBSD
--- 创建 备份数据的 device >-w(P/
USE master 8~tX>q<@q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Jsl2RdI
--- 开始 备份 JIhEkY
BACKUP DATABASE pubs TO testBack `78Bv>[A
4、说明:创建新表 wBcoh~
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) oNZ_7tU
根据已有的表创建新表: Z\?2"4H
A:create table tab_new like tab_old (使用旧表创建新表) q.p.$)
B:create table tab_new as select col1,col2... from tab_old definition only D"J',YN$
5、说明:删除新表 ,DZvBS
drop table tabname S=(<m%f
6、说明:增加一个列 8l_M 0F,
Alter table tabname add column col type DmpT<SI+!
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。 zcKQD )]
7、说明:添加主键: Alter table tabname add primary key(col) w9{C"K?u=
说明:删除主键: Alter table tabname drop primary key(col) W#S8 2
8、说明:创建索引:create [unique] index idxname on tabname(col....) jMgXIK\
删除索引:drop index idxname J91[w?,
注:索引是不可更改的,想更改必须删除重新建。 +? h}e
9、说明:创建视图:create view viewname as select statement /TyGZ@S>m
删除视图:drop view viewname CJ*
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10、说明:几个简单的基本的sql语句 } vmRm*8z
选择:select * from table1 where 范围 )\|+G5#`
插入:insert into table1(field1,field2) values(value1,value2) MfP)Pk5
删除:delete from table1 where 范围 Xx"<^FS[zC
更新:update table1 set field1=value1 where 范围 )P$|9<_q7x
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! < cvh1~>(
排序:select * from table1 order by field1,field2 [desc] CuWJai:nQ;
总数:select count as totalcount from table1 HR}O:2'
求和:select sum(field1) as sumvalue from table1 H+4j.eVzZU
平均:select avg(field1) as avgvalue from table1 ]3rVULU"K-
最大:select max(field1) as maxvalue from table1 xSm;~')g
最小:select min(field1) as minvalue from table1 hW~.F
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11、说明:几个高级查询运算词 Snx!^4+MF
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A: UNION 运算符 %up?70
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 K]hp-QK<
B: EXCEPT 运算符 9af.t
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ,~1"50 Hp@
C: INTERSECT 运算符 Y()"2CCV
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 FQ]/c#J
注:使用运算词的几个查询结果行必须是一致的。 iRzFA!wH
12、说明:使用外连接 ,%M[$S'
A、left outer join: k, HC"?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。 wDJ`#"5p{
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 x4oWZEd
B:right outer join: WMSJU/-P
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。 K#0TD("
C:full outer join: ffZ~r%25{
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。 XBQt:7[<
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二、提升 *m~-8_ >;
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9}(w*>_L
法一:select * into b from a where 1<>1 R4m{D
法二:select top 0 * into b from a M|WBJ'#x0
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) i[v4[C=WB!
insert into b(a, b, c) select d,e,f from b; CM;b_E)9)f
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) JvpGxj
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 E
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `(e :H
4、说明:子查询(表名1:a 表名2:b) S+ kq1R
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) Cn{Hk)6
5、说明:显示文章、提交人和最后回复时间 gcJ!_KZK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Nep4J;
6、说明:外连接查询(表名1:a 表名2:b) mdj%zJ8/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c eb62(:=N6
7、说明:在线视图查询(表名1:a ) Zf'*pp T&q
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6':iW~iI
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 jD:
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select * from table1 where time between time1 and time2 +yGQt3U
select a,b,c, from table1 where a not between 数值1 and 数值2 0MG>77
9、说明:in 的使用方法 1Kg0y71"
select * from table1 where a [not] in ('值1','值2','值4','值6') YW7W6mWspS
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L, JQ\!c
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) LdPLC':}x|
11、说明:四表联查问题: s]arNaaA
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 ..... @60D@Y
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 uDf<D.+5Ze
13、说明:一条sql 语句搞定数据库分页 =BJe)!b
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 #36QO
14、说明:前10条记录 OQVrg2A%(
select top 10 * form table1 where 范围 Sc)^k
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.) ]c.w+<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7]ieBUfS
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 U7r8FL l
(select a from tableA ) except (select a from tableB) except (select a from tableC) Vwkvu&4
17、说明:随机取出10条数据 ARk(\,h
select top 10 * from tablename order by newid() +vBi7#&
18、说明:随机选择记录 dmFn0J-\
select newid() !"<[&
19、说明:删除重复记录 5KCB^`|b>t
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) p>6`jr
20、说明:列出数据库里所有的表名 0RUk^
select name from sysobjects where type='U'
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21、说明:列出表里的所有的 x#rgFY,TY
select name from syscolumns where id=object_id('TableName') 9&6j uL
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。 9t`;~)o
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 3DU1c?M:
显示结果: ?jx]%n fV
type vender pcs 04a
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电脑 A 1 80xr zv
电脑 A 1 u-_r2U
光盘 B 2 pLMt2G
光盘 A 2 'ofj1%c
手机 B 3 _fAgp_)
手机 C 3 $=aO*i
23、说明:初始化表table1 v2T2/y%
TRUNCATE TABLE table1 tne_]+
24、说明:选择从10到15的记录 RNg?o[S
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @^{Hq6_`
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三、技巧 X{9^$/XsJ
1、1=1,1=2的使用,在SQL语句组合时用的较多 rK3kg2H
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如:
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if @strWhere !='' [ks_wvY:'
begin *~rj!N?;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere \pmS*Dt
end UaT%tv>}8#
else 2HbnE&
begin tgRj8
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' bO~y=Pa\
end aDlp>p^E>
我们可以直接写成 R@e'=z[%1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4kOO3[r
2、收缩数据库 %mI0*YRma
--重建索引 k.J%rRneN
DBCC REINDEX
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DBCC INDEXDEFRAG `L1,JE`
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--收缩数据和日志 i'tMpS3
DBCC SHRINKDB XS<>0YM
DBCC SHRINKFILE Qg> NJ\*Q
3、压缩数据库 ~.a"jYb7A}
dbcc shrinkdatabase(dbname) I-#H+\S
4、转移数据库给新用户以已存在用户权限 FO{=^I5YA
exec sp_change_users_login 'update_one','newname','oldname' }=R]<`Sj.j
go t)SZ2G1r
5、检查备份集 q0sf\|'<}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' JK,MK|
6、修复数据库 X>(1fra4
ALTER DATABASE [dvbbs] SET SINGLE_USER _nGx[1G( 5
GO WMbkKC.{J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `/|
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GO awLvLkQb{
ALTER DATABASE [dvbbs] SET MULTI_USER =lacfPS
GO P^Hgm
7、日志清除 _,3ljf?WQM
SET NOCOUNT ON ULx:2jz
DECLARE @LogicalFileName sysname, \!KE_7HRu
@MaxMinutes INT, GwWK'F'2
@NewSize INT mh+T!v$[n)
USE tablename -- 要操作的数据库名 xC76jE4
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Bfb~<rs[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. D%>Bj>xQD
@NewSize = 1 -- 你想设定的日志文件的大小(M) W'G|sk
-- Setup / initialize Iu'9yb
DECLARE @OriginalSize int %-hSa~20
SELECT @OriginalSize = size kBUkE-~
FROM sysfiles [@$ SLl^Y
WHERE name = @LogicalFileName r[9m-#)>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + >t+ ENYb
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + e02Hf{eOfw
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' )@]%:m!ER
FROM sysfiles O>`k@X@9/
WHERE name = @LogicalFileName G?4@[m
CREATE TABLE DummyTrans Jb,54uN
(DummyColumn char (8000) not null) k@xinK%O{
DECLARE @Counter INT, z']6C9m}
@StartTime DATETIME, =<\22d5L
@TruncLog VARCHAR(255) fy+5i^{=
SELECT @StartTime = GETDATE(), XQ1]F{?/H
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' y_PA9#v7
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \p^V~fy7rU
EXEC (@TruncLog) fECV\Z
-- Wrap the log if necessary. Lf_Y4a#
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \((MoQ9Qk
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %:26v
AND (@OriginalSize * 8 /1024) > @NewSize *%uz LW0
BEGIN -- Outer loop. <ZT
C^=3
SELECT @Counter = 0 C-pR$WM:HN
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]($ \7+
BEGIN -- update !vX4_!%
INSERT DummyTrans VALUES ('Fill Log') w4L()eP#?=
DELETE DummyTrans T;M
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SELECT @Counter = @Counter + 1 bH+NRNI]
END k(H&Af+
EXEC (@TruncLog) TX)W.2u=
END .0dGS
SELECT 'Final Size of ' + db_name() + ' LOG is ' + c[2t,+O
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~+.=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' r8"2C#
FROM sysfiles f
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WHERE name = @LogicalFileName w!lk&7Q7Z
DROP TABLE DummyTrans NuOA'e+i
SET NOCOUNT OFF 0 u*a=f=
8、说明:更改某个表 @x `X|>&
exec sp_changeobjectowner 'tablename','dbo' j$T12
9、存储更改全部表 &mX_\w/%
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !B`z|#
@OldOwner as NVARCHAR(128), &JX<)JEB=<
@NewOwner as NVARCHAR(128) re*Zs}(N\
AS -!!]1\S*Y
DECLARE @Name as NVARCHAR(128) Tm^kZuT{
DECLARE @Owner as NVARCHAR(128) 2l?^\9&
DECLARE @OwnerName as NVARCHAR(128) SM~ ~:
DECLARE curObject CURSOR FOR h6k" D4o\
select 'Name' = name, )\yK61aX
'Owner' = user_name(uid) A=kOSq 4Q
from sysobjects +'8a>K^
where user_name(uid)=@OldOwner (IV\sY
order by name ZH~bY2^;
OPEN curObject Cl'$*h
FETCH NEXT FROM curObject INTO @Name, @Owner x[mz`0
WHILE(@@FETCH_STATUS=0) 7V%P
BEGIN #E+ybwA
if @Owner=@OldOwner Oj-\
begin l%}q&_
set @OwnerName = @OldOwner + '.' + rtrim(@Name) .B~}hjOZK
exec sp_changeobjectowner @OwnerName, @NewOwner he(K
end RP$u/x"b
-- select @name,@NewOwner,@OldOwner *AV%=
FETCH NEXT FROM curObject INTO @Name, @Owner 9mxg$P4
END )l9KDObis
close curObject '$Z)2fn7
deallocate curObject e-*@R#x8+
GO +a39 !j
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10、SQL SERVER中直接循环写入数据 o2dO\$'
declare @i int /"J 6``MV
set @i=1 UYxn?W.g
while @i<30 2d*bF.
begin Ck#e54gJX
insert into test (userid) values(@i) *%/O (ohs@
set @i=@i+1 2.WI".&y=
end n
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小记存储过程中经常用到的本周,本月,本年函数 ,c"J[$i$
Dateadd(wk,datediff(wk,0,getdate()),-1) j4,y+9U
Dateadd(wk,datediff(wk,0,getdate()),6) CNb(\]
Dateadd(mm,datediff(mm,0,getdate()),0) XB7*S*"!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) zg3kU65PJE
Dateadd(yy,datediff(yy,0,getdate()),0) U',C-56z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ^R:&c;&,
上面的SQL代码只是一个时间段 _yg;5#3
Dateadd(wk,datediff(wk,0,getdate()),-1) {@CQ
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Dateadd(wk,datediff(wk,0,getdate()),6) Btxtu"]nJo
就是表示本周时间段. ntLEk fK{
下面的SQL的条件部分,就是查询时间段在本周范围内的: I#xdksY
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6!>p<p"Ns
而在存储过程中 s.p>
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /pjl6dJ
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) }$z(?b