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。 +W\f(/ q0
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一、基础 Z2='o_c
1、说明:创建数据库 ac.Ms (D
CREATE DATABASE database-name j|%HIF25
2、说明:删除数据库 }J1tdko#
drop database dbname yo)%J
3、说明:备份sql server NchXt6$i9
--- 创建 备份数据的 device (+3Wgl+]/
USE master ;)e2@'Agl
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9;Ox;;w
--- 开始 备份 [4C:r!
BACKUP DATABASE pubs TO testBack !@'6)/
4、说明:创建新表 %r6y
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kO{s^_qR^c
根据已有的表创建新表: C
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A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only ICkp$u^
5、说明:删除新表 q51Uf_\/
drop table tabname p2udm! )J
6、说明:增加一个列 EC8b=B<DE
Alter table tabname add column col type OYmR<x5y/
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。 i35=Y~P-
7、说明:添加主键: Alter table tabname add primary key(col) `Ru3L#@
说明:删除主键: Alter table tabname drop primary key(col) '-b*EZU8t
8、说明:创建索引:create [unique] index idxname on tabname(col....) 5~WGZc
删除索引:drop index idxname Y=n4K<
注:索引是不可更改的,想更改必须删除重新建。 C[Dav&=^F
9、说明:创建视图:create view viewname as select statement lBFMwJU)
删除视图:drop view viewname )Ocl=H|=
10、说明:几个简单的基本的sql语句 xD[Gq%
选择:select * from table1 where 范围 5
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插入:insert into table1(field1,field2) values(value1,value2) ql?=(b;D
删除:delete from table1 where 范围 jR#~I@q^
更新:update table1 set field1=value1 where 范围 tl'9IGlc
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7C2&NyWJ
排序:select * from table1 order by field1,field2 [desc] | j a-
总数:select count as totalcount from table1 9n5<]Q(
求和:select sum(field1) as sumvalue from table1 Bk\Gj`"7
平均:select avg(field1) as avgvalue from table1 &0(
最大:select max(field1) as maxvalue from table1 Y.U[wL>
最小:select min(field1) as minvalue from table1 z2hc.29t
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11、说明:几个高级查询运算词 ,qrQ"r9
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A: UNION 运算符 ]$\|ktY!
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。
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B: EXCEPT 运算符 ~~,rp) )
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 &gE 75B
C: INTERSECT 运算符 WJ9cZL
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 FwZ>{~?3
注:使用运算词的几个查询结果行必须是一致的。 13&0rLS
12、说明:使用外连接 LtKI3ou
A、left outer join: d@G}~&.|
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 t"YNgC ^
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {E0z@D)U-
B:right outer join: ?cEskafb>
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 rJInj>|{=
C:full outer join: 'vaLUy9]
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 D\YE^8/
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二、提升 fQ=MJ7l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9A7@
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法一:select * into b from a where 1<>1 wB{;bB{
法二:select top 0 * into b from a zn@N'R/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ,mL
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insert into b(a, b, c) select d,e,f from b; oejfU;+$
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) EK$Kee}~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `O8b1-1q~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Y05P'Q
4、说明:子查询(表名1:a 表名2:b) [J0v&{)?
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) oq_6L\
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5、说明:显示文章、提交人和最后回复时间 P0-Fc@&Y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b l@hjP1o
6、说明:外连接查询(表名1:a 表名2:b) sW^a`VM
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;u" <KG?
7、说明:在线视图查询(表名1:a ) yRYWch
select * from (SELECT a,b,c FROM a) T where t.a > 1; {A o,t+j
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 LN_OD5gZ
select * from table1 where time between time1 and time2 $8BE[u|H2
select a,b,c, from table1 where a not between 数值1 and 数值2 y9|K|xO[
9、说明:in 的使用方法 M}hrO-C
select * from table1 where a [not] in ('值1','值2','值4','值6') 9=/N|m8.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .6pOvGKb
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -n? g~(/P
11、说明:四表联查问题: 1SV^ ){5I
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ,s^<X85gp\
12、说明:日程安排提前五分钟提醒 i$KpDXP\
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^ 2u/n
13、说明:一条sql 语句搞定数据库分页 jAsO8
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 -6Mm#sX
14、说明:前10条记录 D["MUB4l
select top 10 * form table1 where 范围 HZ*0QgW\(5
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.) 0%;146.p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =BZ?- mIU
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 vY*\R0/a
(select a from tableA ) except (select a from tableB) except (select a from tableC) qOG}[%<^n7
17、说明:随机取出10条数据 dy>|cj
select top 10 * from tablename order by newid() K$REZe
18、说明:随机选择记录 fH8!YQG8$
select newid() ]PNowS\
19、说明:删除重复记录 ~L+]n0*
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) NgB 7?]vu
20、说明:列出数据库里所有的表名 G7* h{nE
select name from sysobjects where type='U' &}`K^5K|O:
21、说明:列出表里的所有的 v&MU=Tcqi
select name from syscolumns where id=object_id('TableName') y02u?wJ
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。 5GAy "Xd
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 8Vt4HD 08
显示结果: $X+u={]
type vender pcs ad`_>lA4Lp
电脑 A 1 }1%r%TikY
电脑 A 1 [D'Gr*5~{
光盘 B 2 q3'o|pp
光盘 A 2 /axTh
手机 B 3 i!MwBYk
手机 C 3 P?3{z="LzJ
23、说明:初始化表table1 uiBTnG"
TRUNCATE TABLE table1 wh~sZ
24、说明:选择从10到15的记录 RFG$X-.e
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc DPJh5d
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三、技巧 $ehg@WK}.
1、1=1,1=2的使用,在SQL语句组合时用的较多 ->yeJTsE9
"where 1=1" 是表示选择全部 "where 1=2"全部不选, N5q725zJ
如: ZxS&4>.
if @strWhere !='' )45_]tk>
begin (Imp
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere vg5NY =O
end [a8+(
else d]M[C[TOX
begin bx(w:]2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "oE* 9J?e
end U4wpjHg
我们可以直接写成 xtJAMo>g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere =FBIrw{w
2、收缩数据库 {of]/3=
--重建索引 ]M4NpUM
DBCC REINDEX vbn>mg5
DBCC INDEXDEFRAG cjg=nTsBA
--收缩数据和日志 `Ei"_W
DBCC SHRINKDB &] 3:D
DBCC SHRINKFILE `45d"B
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3、压缩数据库 *:QXz<_x+
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 qWB%),`j>
exec sp_change_users_login 'update_one','newname','oldname' !Y%D
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go deM~[1e[
5、检查备份集 $j
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' #'NY}6cb$
6、修复数据库 d8.ajeN]o
ALTER DATABASE [dvbbs] SET SINGLE_USER ]7F)bIG[
GO WLy7'3@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK )[DpK=[N^p
GO |Q u_E
ALTER DATABASE [dvbbs] SET MULTI_USER /'Bdq?!B&
GO 6 ">oo-
7、日志清除 3*\8p6G
SET NOCOUNT ON O<a3DyUa;
DECLARE @LogicalFileName sysname, *eoq=,O
@MaxMinutes INT, -wIM0YJ
@NewSize INT F`D9Zfd
USE tablename -- 要操作的数据库名 B'/Icg.T
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 v|To+P6b
@MaxMinutes = 10, -- Limit on time allowed to wrap log. D'?]yyrf
@NewSize = 1 -- 你想设定的日志文件的大小(M) ./)j5M
-- Setup / initialize w#d} TY
DECLARE @OriginalSize int 7NUenCdc
SELECT @OriginalSize = size Dtt\~m;AR
FROM sysfiles &"O_wd[+:
WHERE name = @LogicalFileName [+7"{UvT
SELECT 'Original Size of ' + db_name() + ' LOG is ' + cqHw^{'8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + d'q;+jnP
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Qf~| S9,
FROM sysfiles 7rPLnB]
WHERE name = @LogicalFileName ujNt(7Cz
CREATE TABLE DummyTrans Wb'*lT0=
(DummyColumn char (8000) not null) EUXV/QV{
DECLARE @Counter INT, K5+!(5V~
@StartTime DATETIME, A<;0L . J
@TruncLog VARCHAR(255) 7ozYq_ $
SELECT @StartTime = GETDATE(), u-1@~Z
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @ p"NJx"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) e)br`CD%
EXEC (@TruncLog) &?v#| qIh
-- Wrap the log if necessary. {!g?d<*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired f!^)!~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ZG!x$yi$
AND (@OriginalSize * 8 /1024) > @NewSize _i.({s&_9
BEGIN -- Outer loop. Fv;u1Atiw
SELECT @Counter = 0 S{Rh'x\B
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) d[yrNB6|
BEGIN -- update @<VG8{
INSERT DummyTrans VALUES ('Fill Log') UVnrDhd!0
DELETE DummyTrans M$gvq:}kt
SELECT @Counter = @Counter + 1 8R
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END ]C+eJ0"A
EXEC (@TruncLog) !OV|I
END q^u6f?B
SELECT 'Final Size of ' + db_name() + ' LOG is ' + G|<] Ma9x
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + O5c_\yv=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' '/n\Tg+
FROM sysfiles a =9vS{
WHERE name = @LogicalFileName GsR-#tV@
DROP TABLE DummyTrans nz}]C04:-
SET NOCOUNT OFF q`h7H][(A
8、说明:更改某个表 9 Zs#Ky/
exec sp_changeobjectowner 'tablename','dbo' I4A;
9、存储更改全部表 _QD/!~O
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |>M-+@gj
@OldOwner as NVARCHAR(128), p, !1 3X
@NewOwner as NVARCHAR(128) ;>cLbjD
AS "[FCQ
DECLARE @Name as NVARCHAR(128) 1VRqz5
DECLARE @Owner as NVARCHAR(128) YmdsI+DbIu
DECLARE @OwnerName as NVARCHAR(128) oM/B.U2a
DECLARE curObject CURSOR FOR o:p{^D@#k
select 'Name' = name, hQ\#Fhu7
'Owner' = user_name(uid) +>n.T
from sysobjects "4J?JR
where user_name(uid)=@OldOwner kO
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order by name ,^UcRZ8.H
OPEN curObject bkJwP s
FETCH NEXT FROM curObject INTO @Name, @Owner ke{DFqh
WHILE(@@FETCH_STATUS=0) )G}sb*+v?
BEGIN *g}vT8w'}
if @Owner=@OldOwner [~zE,!
begin s0x@
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) M'pY-/.
exec sp_changeobjectowner @OwnerName, @NewOwner ]W89.><%14
end B3ohHxHu
-- select @name,@NewOwner,@OldOwner ,C5@P+A
FETCH NEXT FROM curObject INTO @Name, @Owner H620vlC}V
END Yb,G^+;
close curObject THegPD67J
deallocate curObject C?_t8G./_
GO ]9!Gg
10、SQL SERVER中直接循环写入数据 W$x K^}
declare @i int ?S;et2f
set @i=1 7$E2/@f
while @i<30 tSw~_s_V
begin A5(kOtgiT
insert into test (userid) values(@i) XFLjVrX[
set @i=@i+1 )wyu+_:
end %'K+$
小记存储过程中经常用到的本周,本月,本年函数 55u^u F
Dateadd(wk,datediff(wk,0,getdate()),-1) NK*:w *SOI
Dateadd(wk,datediff(wk,0,getdate()),6) dja9XWOg
Dateadd(mm,datediff(mm,0,getdate()),0) J:M<9W
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) z.Ve#~\
Dateadd(yy,datediff(yy,0,getdate()),0) C/grrw
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) M[&.kH
上面的SQL代码只是一个时间段 $n_sGr
Dateadd(wk,datediff(wk,0,getdate()),-1) $)WH^Ir~
Dateadd(wk,datediff(wk,0,getdate()),6) 8.
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就是表示本周时间段. qrORP3D@
下面的SQL的条件部分,就是查询时间段在本周范围内的: @i1 .5z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 3 8ls 4v3
而在存储过程中 /eI,]CB'z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "1pZzad
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xq#]n^