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。 d<HO~+9
f1elzANy
,=c(P9}^
一、基础 Gr)G-zE
1、说明:创建数据库 1;i|GXY:h
CREATE DATABASE database-name 4GG>n
2、说明:删除数据库 #n15_cd
drop database dbname =n_z `I
3、说明:备份sql server ,oSn<$%/q
--- 创建 备份数据的 device qN9 ?$\
USE master YktZXc?iI<
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' x >tm[k
--- 开始 备份 jt: *Y
BACKUP DATABASE pubs TO testBack 4<)*a]\c5M
4、说明:创建新表 gy~2LY !}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `-R&4%t%
根据已有的表创建新表: v}D0t]
A:create table tab_new like tab_old (使用旧表创建新表) .X"&kO>G
B:create table tab_new as select col1,col2... from tab_old definition only I&gd"F _v}
5、说明:删除新表 b!Nr
drop table tabname 1LhZmv
6、说明:增加一个列 h(J$-SUs
Alter table tabname add column col type ?D_iib7
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 o:"(\$
7、说明:添加主键: Alter table tabname add primary key(col) }bdoJ5
说明:删除主键: Alter table tabname drop primary key(col) 9V&+xbR&
8、说明:创建索引:create [unique] index idxname on tabname(col....) m,62'
删除索引:drop index idxname 6A|XB3
注:索引是不可更改的,想更改必须删除重新建。 yGrnzB6|
9、说明:创建视图:create view viewname as select statement 6gO(
8
删除视图:drop view viewname GO@<?>K
10、说明:几个简单的基本的sql语句
?*r%*CL
选择:select * from table1 where 范围 'irwecd8
插入:insert into table1(field1,field2) values(value1,value2) `
"-P g5
删除:delete from table1 where 范围 4GeN<9~YS
更新:update table1 set field1=value1 where 范围 r$'.$k\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ]@Z
nP,8
排序:select * from table1 order by field1,field2 [desc] &(l.jgqg&
总数:select count as totalcount from table1 1ah,Zth2
求和:select sum(field1) as sumvalue from table1 ,Shzew+
平均:select avg(field1) as avgvalue from table1 wq!9wk9
最大:select max(field1) as maxvalue from table1 :hW(2=%
最小:select min(field1) as minvalue from table1 tX@y ]"
_T~&kwe
MU2kA&LH
PYs0w6o
11、说明:几个高级查询运算词 1>Vq<z
A-_M=\
rz-61A) _
A: UNION 运算符 K`uPPyv
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。 Nq\)o{<1
B: EXCEPT 运算符 <Kr`R+Q$DN
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ADB)-!$xoi
C: INTERSECT 运算符 O;McPw<&\:
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。 2@pEiq3
注:使用运算词的几个查询结果行必须是一致的。 E_[a|N"D
12、说明:使用外连接 z8%qCq
A、left outer join: zSk`Ou8M
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。 * a1q M?
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 `k8j FB C
B:right outer join: }NGP!
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。 x?u@
j7[
C:full outer join: S?a4IK
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。 ~)>.%`v&
ZGI<L
?p 4iXHE
二、提升 >"b\$",~6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) c93 Ok |
法一:select * into b from a where 1<>1 &`vThs[x
法二:select top 0 * into b from a :[f[-F
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +~of#
insert into b(a, b, c) select d,e,f from b; !+z^VcV
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) #Cy3x-!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 LjW32>B
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +|8.ymvm
4、说明:子查询(表名1:a 表名2:b) ,L~aa?Nb-
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) 8y_(Iu|:
5、说明:显示文章、提交人和最后回复时间 c9Cc%EK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -e_TJA
6、说明:外连接查询(表名1:a 表名2:b) =5fY3%^b{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c YO?o$Hv16
7、说明:在线视图查询(表名1:a ) ht>/7.p]
select * from (SELECT a,b,c FROM a) T where t.a > 1; x>BFK@#
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 )b=vBs`%
select * from table1 where time between time1 and time2 K7(k_4
select a,b,c, from table1 where a not between 数值1 and 数值2 >hq{:m
9、说明:in 的使用方法 O'#;Ge/,
select * from table1 where a [not] in ('值1','值2','值4','值6') &b*v7c=o
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0+SZ-]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *<SXzJ(
11、说明:四表联查问题: gGBRfq>
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ~UQ<8`@a
12、说明:日程安排提前五分钟提醒 5!$sQ@#}D
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +opym!\
13、说明:一条sql 语句搞定数据库分页 O7LJ-M
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 -b8SaLak
14、说明:前10条记录 VYh/URU>
select top 10 * form table1 where 范围 (4yXr|to}
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.) d7QUg6=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @(E6P;+{
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 GE=S.P;
(select a from tableA ) except (select a from tableB) except (select a from tableC) @"/H
er
17、说明:随机取出10条数据 '73}{" '
select top 10 * from tablename order by newid() Qy4Pw\
18、说明:随机选择记录 !v9`oL26
select newid() '/9MN;_
19、说明:删除重复记录 wxj}k7_(`A
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) QfPw50N;
20、说明:列出数据库里所有的表名 @W
@,8e]c
select name from sysobjects where type='U' zw$\d1-+h
21、说明:列出表里的所有的 I5g|)Y Q
select name from syscolumns where id=object_id('TableName') 3="vOSJ6&
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。
&0|Z FXPd
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type OK`^DIr5l
显示结果: PvjZoF["
type vender pcs PU1YR;[Fe
电脑 A 1 F6Q%<p a
电脑 A 1 8'TIDu
光盘 B 2 7P*\|Sxk%
光盘 A 2 fi ~@J`
手机 B 3 )t7MD(
手机 C 3 GVn'p
Wg
23、说明:初始化表table1 '/0e!x/8
TRUNCATE TABLE table1 "zTy_0[;
24、说明:选择从10到15的记录 h&d"| <
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7 H:y=?X6
F]>+pU
4@<wN \'
xE!0p EHd
三、技巧 8@S]P0lk
1、1=1,1=2的使用,在SQL语句组合时用的较多 4tUt"N
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U#iW1jPE2
如: ed_+bCNy
if @strWhere !='' l7VTuVGUJ
begin yIngenr$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere bT
T>
end 6biR5&Y5U&
else 8<C@I/
begin $9X?LGUz
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' vJVh%l+
end .v'`TD).6
我们可以直接写成 NYG!\u\Rm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere e 6>j
gy
2、收缩数据库 ^*B@=
--重建索引 X !0 7QKs
DBCC REINDEX |F<iu2\
DBCC INDEXDEFRAG mSZg;7DE3*
--收缩数据和日志 wS&D-!8v
DBCC SHRINKDB KECW~e`
DBCC SHRINKFILE di9OQ*6a7
3、压缩数据库 >JY\h1+ H
dbcc shrinkdatabase(dbname) \b!E"I_^
4、转移数据库给新用户以已存在用户权限 3#]II j`\
exec sp_change_users_login 'update_one','newname','oldname' >m<T+{`
go E?KPez
5、检查备份集 whP5u/857
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' B<qsa QG
6、修复数据库 L{)t(H>O
ALTER DATABASE [dvbbs] SET SINGLE_USER CRNi*u
GO 2g?q4e,
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK hm0A%Js
GO I} +up,B]o
ALTER DATABASE [dvbbs] SET MULTI_USER Y TY(Et1i
GO y3QS!3I
7、日志清除 !io1~GpKS
SET NOCOUNT ON ;C:|m7|
DECLARE @LogicalFileName sysname, a'Zw^g
@MaxMinutes INT, Wc!]X.|9*
@NewSize INT HyKA+7}
USE tablename -- 要操作的数据库名 .q4$)8[Pg
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9Hb|$/FD
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {.KD#W
$5
@NewSize = 1 -- 你想设定的日志文件的大小(M) p>3QW3<
-- Setup / initialize a;-%C{S9r
DECLARE @OriginalSize int I\c7V~^hnG
SELECT @OriginalSize = size QUvSeNSp
FROM sysfiles %N(>B_t\
WHERE name = @LogicalFileName #9.%>1{6Y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]SPuNBsy)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + +_bxza(ma{
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' JEWc{)4QD
FROM sysfiles aot2F60J,
WHERE name = @LogicalFileName @V5i
CREATE TABLE DummyTrans @H~oOf
(DummyColumn char (8000) not null) [UC_
DECLARE @Counter INT, Iu`S0#+
@StartTime DATETIME, g.%} +5
@TruncLog VARCHAR(255) s3Zt)xQ3
SELECT @StartTime = GETDATE(), cjO%X
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' .sM,U
DBCC SHRINKFILE (@LogicalFileName, @NewSize) x{K"z4xbI
EXEC (@TruncLog) xJU]py~o
-- Wrap the log if necessary. *_#2|96)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired M
l@F
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 6\I1J=
C
AND (@OriginalSize * 8 /1024) > @NewSize 6J}Yr5oD
BEGIN -- Outer loop. 6vps`k$,~
SELECT @Counter = 0 =>evkaj
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) mXS]SE
BEGIN -- update U/cj_}uX
INSERT DummyTrans VALUES ('Fill Log') jV%=YapF
DELETE DummyTrans )S`[ gK
SELECT @Counter = @Counter + 1 WvfM.D!
END g"kI1^[nj
EXEC (@TruncLog) UpE+WzY
END }' Y)"8AIA
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v'Ehr**]+
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e?B}^Dk0i
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' C8T0=o/-`
FROM sysfiles p8@&(+z
WHERE name = @LogicalFileName FkuD Gg~a
DROP TABLE DummyTrans >qr/1mW
SET NOCOUNT OFF mf{M-(6'
8、说明:更改某个表 ='4)E6ea?
exec sp_changeobjectowner 'tablename','dbo' d6JW"
9、存储更改全部表 qz3
Z'
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch chKEGosbF
@OldOwner as NVARCHAR(128), =jS$piw.
@NewOwner as NVARCHAR(128) _O'!C!K6
AS *x]*%
DECLARE @Name as NVARCHAR(128) ~x<?Pj
DECLARE @Owner as NVARCHAR(128) xLi3|^q
DECLARE @OwnerName as NVARCHAR(128) X/vyb^:U
DECLARE curObject CURSOR FOR $\/^O94-l
select 'Name' = name, 1ywdcg
'Owner' = user_name(uid) K*b* ]hf{
from sysobjects 3#dz6+
where user_name(uid)=@OldOwner C#yRop_d]o
order by name FBB<1( {A
OPEN curObject G}+@C]
FETCH NEXT FROM curObject INTO @Name, @Owner {I$iD
WHILE(@@FETCH_STATUS=0) hwL`9.w
BEGIN Z2})n
-
if @Owner=@OldOwner u7RlxA:
begin sP2Uj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZS(%!+ M
exec sp_changeobjectowner @OwnerName, @NewOwner +lVA$]d
end 'xG J;pY
-- select @name,@NewOwner,@OldOwner !5?_)
FETCH NEXT FROM curObject INTO @Name, @Owner _Z9d.-
END .s,04xW\
close curObject _xm<zy{`S
deallocate curObject }d>.Nj#zh
GO QKq4kAaJ!
10、SQL SERVER中直接循环写入数据 |%ZJN{!R
declare @i int :3D6OBkB
set @i=1 YG:^gi
while @i<30 (Sgsy^|N
begin 9s[
insert into test (userid) values(@i) 0!ZaR6
set @i=@i+1 `O0Qtq.
end c^pQitPv
小记存储过程中经常用到的本周,本月,本年函数 "Ueq
Dateadd(wk,datediff(wk,0,getdate()),-1) 9*K-d'm
Dateadd(wk,datediff(wk,0,getdate()),6) a@|H6:|
Dateadd(mm,datediff(mm,0,getdate()),0) ob2_=hQnC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6D2ot&5WW
Dateadd(yy,datediff(yy,0,getdate()),0) !m9hL>5vR
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) rEC
上面的SQL代码只是一个时间段 00dY?d{[D
Dateadd(wk,datediff(wk,0,getdate()),-1) ]cS(2hP7
Dateadd(wk,datediff(wk,0,getdate()),6) a)=|{QR>W
就是表示本周时间段. (?^ F }]
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^p9V5o
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Tsb}\
而在存储过程中 N wNxO
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \7*|u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) UF-'(