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。 YPxM<Gfa8
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一、基础 AIZ]jq
1、说明:创建数据库 .[_L=_.
CREATE DATABASE database-name &q9T9AOS
2、说明:删除数据库 v/ _
drop database dbname c
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3、说明:备份sql server r]6C
--- 创建 备份数据的 device |:gf lseE
USE master nR*ryv
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' m;,N)<~
--- 开始 备份 mHRiugb!
BACKUP DATABASE pubs TO testBack PpzP 7
4、说明:创建新表 'tH_p
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) s%W C/ZK
根据已有的表创建新表: ,y#Kv|R
A:create table tab_new like tab_old (使用旧表创建新表) o2F)%T DY
B:create table tab_new as select col1,col2... from tab_old definition only NCDvobYJ
5、说明:删除新表 {z{bY\
drop table tabname A6thXs2
6、说明:增加一个列 A*\.NTM
Alter table tabname add column col type z:wutqru
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。 :;9F>?VN>0
7、说明:添加主键: Alter table tabname add primary key(col) r 8RoE`/T
说明:删除主键: Alter table tabname drop primary key(col) ,>%}B3O:Y=
8、说明:创建索引:create [unique] index idxname on tabname(col....) %$.3V#?
删除索引:drop index idxname K|[*t~59
注:索引是不可更改的,想更改必须删除重新建。 NPp;78O0[
9、说明:创建视图:create view viewname as select statement 'd9INz.
删除视图:drop view viewname %#kg#@z_`e
10、说明:几个简单的基本的sql语句 %lGl,me H
选择:select * from table1 where 范围 gDpVeBd[
插入:insert into table1(field1,field2) values(value1,value2) 1ukTA@Rj&
删除:delete from table1 where 范围 EFM5,gB.m
更新:update table1 set field1=value1 where 范围 YpVD2.jy
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! T{-CkHf9Q
排序:select * from table1 order by field1,field2 [desc] ~UP[A'9jJ
总数:select count as totalcount from table1 A
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求和:select sum(field1) as sumvalue from table1 C&(N
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平均:select avg(field1) as avgvalue from table1 Tw-;7Ae
最大:select max(field1) as maxvalue from table1 GBPo8L"9
最小:select min(field1) as minvalue from table1 FOE4>zE
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11、说明:几个高级查询运算词 NXrJfp
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A: UNION 运算符 _9F9W{'
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 a.k.n<
B: EXCEPT 运算符
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 iP7(tnlW$
C: INTERSECT 运算符 rX2.i7i,
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。 yPb" V
注:使用运算词的几个查询结果行必须是一致的。 !$gR{XH$]
12、说明:使用外连接 GjvOM y
A、left outer join: N5lDS
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。 Pd_U7&w,5
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 9y"@(
B:right outer join: i9,geQ7d
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。 p8Qk'F=h
C:full outer join: 8;JWK3Gv
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。 '-Vt|O_Q
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二、提升 t.i 8
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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) ;DfY#-
法一:select * into b from a where 1<>1 _@
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法二:select top 0 * into b from a 286jI7 T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ,l\-xSM
insert into b(a, b, c) select d,e,f from b; L>Fa^jq5
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) w;4<h8Wn5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 <L8'! q}
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TNe l/
4、说明:子查询(表名1:a 表名2:b) KJ)k =mJ
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) ,is3&9
5、说明:显示文章、提交人和最后回复时间 S%Uutj\/W
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X^wt3<Kbf
6、说明:外连接查询(表名1:a 表名2:b) 2} /aFR
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%JuC2
7、说明:在线视图查询(表名1:a ) f<d`B]$(
select * from (SELECT a,b,c FROM a) T where t.a > 1; s<<ooycBrQ
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 ];[}:f
select * from table1 where time between time1 and time2 dO!
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select a,b,c, from table1 where a not between 数值1 and 数值2 ^BikV
9、说明:in 的使用方法 *av<E
select * from table1 where a [not] in ('值1','值2','值4','值6') E Nhl&J
10、说明:两张关联表,删除主表中已经在副表中没有的信息 f@wquG'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) KQ!8ks]
11、说明:四表联查问题: <KL,G};0pm
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 ..... /[
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12、说明:日程安排提前五分钟提醒 PUMXOTu]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "c%0P"u
13、说明:一条sql 语句搞定数据库分页 Fo5FNNiID
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 _Xe>V0
14、说明:前10条记录 Tztu}t]N
select top 10 * form table1 where 范围 [
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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.) '}53f2%gKa
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J?"B%B5c
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 &N^9JxN?8
(select a from tableA ) except (select a from tableB) except (select a from tableC) aFX=C>M
17、说明:随机取出10条数据 7WLy:E"
select top 10 * from tablename order by newid() uP)'FI
18、说明:随机选择记录 _^Ubs>d=*
select newid() NvceYKp:
19、说明:删除重复记录 S6Q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -">;-3,K
20、说明:列出数据库里所有的表名 vxBgGl
select name from sysobjects where type='U' e:DCej^z
21、说明:列出表里的所有的 oM>l#><nq
select name from syscolumns where id=object_id('TableName') ~D j8z+^
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。 'urafE4M
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 we//|fA<
显示结果: [6Izlh+D
type vender pcs Y8~"vuIE5
电脑 A 1 QOGvC[*`<T
电脑 A 1 EU/C@B2*Dl
光盘 B 2 C_}]`[
光盘 A 2 {H>gtpVy
手机 B 3 mp1@|*Sn
手机 C 3 Uiw2oi&_
23、说明:初始化表table1 3wF;GG
TRUNCATE TABLE table1 nfbR
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24、说明:选择从10到15的记录 GY'%+\*tj
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #jvtUS \
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三、技巧 2`K=Hby
1、1=1,1=2的使用,在SQL语句组合时用的较多 gh]cXuph
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ZPLm]I\]
如: AofKw
if @strWhere !='' hE D}h![
begin g
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `r6 ,+&
end Q~
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else `g=J%p
begin 6xx ?A>:
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -$ls(oot
end 3qC}0CP*
我们可以直接写成 q"lSZ;
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere <dtGK~_
2、收缩数据库 6@5+m
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--重建索引 >1Ibc=}g
DBCC REINDEX )D7m,Wi+
DBCC INDEXDEFRAG D%pF;XY
--收缩数据和日志 L,/%f<wd
DBCC SHRINKDB D;*SnU(9L
DBCC SHRINKFILE b{&)6M)zo
3、压缩数据库 Dcgo%F-W
dbcc shrinkdatabase(dbname) ?dg[:1R}
4、转移数据库给新用户以已存在用户权限 Se}c[|8
exec sp_change_users_login 'update_one','newname','oldname' Czu9o;xr
go 194)QeoFw
5、检查备份集 CY5Z{qiX
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ITI)soa~
6、修复数据库 A}9`S6 @@
ALTER DATABASE [dvbbs] SET SINGLE_USER )*J^K?!S
GO -uG+BraI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK %J?xRv!
GO Q(?#'<.#
ALTER DATABASE [dvbbs] SET MULTI_USER JX;G<lev
GO FDs>m
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7、日志清除 )Nw8O{\
SET NOCOUNT ON YK'<NE3 4
DECLARE @LogicalFileName sysname, z>Y-fN`,
@MaxMinutes INT, rq].UCj
@NewSize INT Xc-'Y"}|`t
USE tablename -- 要操作的数据库名 #=A)XlZMd
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 G9cUD[GB
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *])
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@NewSize = 1 -- 你想设定的日志文件的大小(M) ]h+j)J}[A
-- Setup / initialize qR8Lh( "i
DECLARE @OriginalSize int FcU SE
SELECT @OriginalSize = size uw_Y\F-$
FROM sysfiles R&k<AZ
WHERE name = @LogicalFileName \ Gvm9M
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8Fu(Ft^9
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "<1{9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' eq;uO6[
FROM sysfiles }&J q}j
WHERE name = @LogicalFileName {4Cmu;u
CREATE TABLE DummyTrans 'zTLl8P
(DummyColumn char (8000) not null) '-~~-}= sJ
DECLARE @Counter INT, 1>h]{%I
@StartTime DATETIME, u&7[n_
@TruncLog VARCHAR(255) <\^8fn
SELECT @StartTime = GETDATE(), }Zn}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' aX'*pK/-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) sDlO#
EXEC (@TruncLog) aEeodA<(
-- Wrap the log if necessary. Z@!+v19^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired e*NnVys
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /nA{#HY
AND (@OriginalSize * 8 /1024) > @NewSize VpDbHAg
BEGIN -- Outer loop. BW4J> {
SELECT @Counter = 0 iqWQ!r^
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ggR.4&<
BEGIN -- update gjD Ho$
INSERT DummyTrans VALUES ('Fill Log') hz@bW2S.
DELETE DummyTrans E ~<JC"]
SELECT @Counter = @Counter + 1 1oGw4kD^x
END )Ql%r?(F+
EXEC (@TruncLog) Vt#.eL)Ee
END e(t\g^X
SELECT 'Final Size of ' + db_name() + ' LOG is ' + E:nF$#<'N
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + s.C_Zf~3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' aqk!T%fg
FROM sysfiles b8 likP"T
WHERE name = @LogicalFileName M .mfw#*
DROP TABLE DummyTrans t'ql[
SET NOCOUNT OFF eeB{c.#
8、说明:更改某个表 uKHxe~
exec sp_changeobjectowner 'tablename','dbo' DB}eA N/
9、存储更改全部表 4H&+dRI"
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Rima;9.Y0
@OldOwner as NVARCHAR(128), +23xev
@NewOwner as NVARCHAR(128) U>N1Od4vTO
AS L4nYXW0y
DECLARE @Name as NVARCHAR(128) wbl&
DECLARE @Owner as NVARCHAR(128) ZD{LXJ{Vm
DECLARE @OwnerName as NVARCHAR(128) 6j}9V
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DECLARE curObject CURSOR FOR 4,DeHJjAlE
select 'Name' = name, t b}V5VH
'Owner' = user_name(uid) ( a#BV}=
from sysobjects v.qrz"98-
where user_name(uid)=@OldOwner 4.t-i5
order by name %EB/b
OPEN curObject T6=u P)!K
FETCH NEXT FROM curObject INTO @Name, @Owner a&? :P1$
WHILE(@@FETCH_STATUS=0) Q^")jPd
BEGIN Y}wyw8g/
if @Owner=@OldOwner oUlVI*~ND
begin ujpJ@OWj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 3^yK!-Wp(
exec sp_changeobjectowner @OwnerName, @NewOwner
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end jmZI7?<z
-- select @name,@NewOwner,@OldOwner o`-msz
FETCH NEXT FROM curObject INTO @Name, @Owner +
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END }N52$L0[
close curObject ^iV)MTT
deallocate curObject A.w.rVDD
GO 6D3B^.rj]
10、SQL SERVER中直接循环写入数据 X"%gQ.1|{j
declare @i int yJIscwF
set @i=1 o }m3y
while @i<30 vnuN6M{
begin ;RlxD 4p
insert into test (userid) values(@i) jmG~Un M
set @i=@i+1 CU!Dhm/U
end |vj/Wwr
小记存储过程中经常用到的本周,本月,本年函数 2D5StCF$O
Dateadd(wk,datediff(wk,0,getdate()),-1) La[V$+Y
Dateadd(wk,datediff(wk,0,getdate()),6) [Y `W
Dateadd(mm,datediff(mm,0,getdate()),0) `Urhy#LC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) < =IFcN
Dateadd(yy,datediff(yy,0,getdate()),0) ?}Y]|c^W
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5|)W.*Q
上面的SQL代码只是一个时间段 d&>^&>?$zh
Dateadd(wk,datediff(wk,0,getdate()),-1) cH2K )~
Dateadd(wk,datediff(wk,0,getdate()),6) -XG@'P_
就是表示本周时间段. 6_B]MN!(
下面的SQL的条件部分,就是查询时间段在本周范围内的: }^\oCR@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~a2}(]
而在存储过程中 8 LCb+^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) kyV8K#}%8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) "#g}ve,