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。 Ng;E]2"
WH'[~O
A\z[/3& RK
一、基础 %2qvK}
1、说明:创建数据库 )8LCmvQ
CREATE DATABASE database-name Zkxt>%20~
2、说明:删除数据库 x2K.5q>
drop database dbname hEEbH@b
3、说明:备份sql server *=r,V
--- 创建 备份数据的 device v?Y9z!M
USE master +gT?{;3[i
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -
d>)
--- 开始 备份 ZM4q@O)/
BACKUP DATABASE pubs TO testBack B23R9.FK
4、说明:创建新表 lm@<i4%$F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^#"!uCq]gM
根据已有的表创建新表: oOJN?97!k
A:create table tab_new like tab_old (使用旧表创建新表) E#_}y}7JY
B:create table tab_new as select col1,col2... from tab_old definition only >Wy@J]Y#
5、说明:删除新表 IURi90Ir
drop table tabname =DF7l<&km
6、说明:增加一个列 [n66ZY#U]
Alter table tabname add column col type +KD~/}C%-
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 4d6F4G4U
7、说明:添加主键: Alter table tabname add primary key(col) =u73AM}
说明:删除主键: Alter table tabname drop primary key(col) ZEHz/Y%
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7G2TT a
删除索引:drop index idxname l} h<2
注:索引是不可更改的,想更改必须删除重新建。 YMJjO0
9、说明:创建视图:create view viewname as select statement i mJ{wF
删除视图:drop view viewname mDj:w#q
10、说明:几个简单的基本的sql语句 dr:)+R
选择:select * from table1 where 范围 V&NOp
插入:insert into table1(field1,field2) values(value1,value2) ^$yr-p%-
删除:delete from table1 where 范围 [l'~>
更新:update table1 set field1=value1 where 范围 PsLuyGR.<
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =;c? 6{<1
排序:select * from table1 order by field1,field2 [desc] QbS w<V
总数:select count as totalcount from table1 S{J$[!F
求和:select sum(field1) as sumvalue from table1 %.<w8ag
平均:select avg(field1) as avgvalue from table1 aA0aW=R
最大:select max(field1) as maxvalue from table1 VJJw"4DJ
最小:select min(field1) as minvalue from table1 V^.~m;ETu]
~M43#E[oOF
G|X1c}zAL
%'t~+_
11、说明:几个高级查询运算词 :9K5zD
*gZ4Ub|O
o),i2
A: UNION 运算符 [O(78n$$
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。 }&;0:hw%
B: EXCEPT 运算符 >*Y~I0>
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。 ,?i#NN5p
C: INTERSECT 运算符 `EV[uj&1S
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。 k(hes3JV
注:使用运算词的几个查询结果行必须是一致的。 N6yqA)z?;
12、说明:使用外连接 (~/D*<A
A、left outer join: $NJi]g|<3
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 k,b(MAiQ0
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c O^oFH
OpFh
B:right outer join: m.S@ e8kS
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 &*L:4By)]
C:full outer join: #p*OLQ3~
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 hIPDJ1a
^K&&O{
t~X wF(";
二、提升 a<c % Xy/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) `^(6{p ?
法一:select * into b from a where 1<>1 UHweV:(|T
法二:select top 0 * into b from a 0.|tKetHq
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) sDWX} NV
insert into b(a, b, c) select d,e,f from b; _vvnxG!x&
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) h^34{pKDn
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 hRGK W
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. c9iCH~
4、说明:子查询(表名1:a 表名2:b) #).om*Xh
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) /3rt]h"
5、说明:显示文章、提交人和最后回复时间 Lj({
T'f(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;c<:"ad(
6、说明:外连接查询(表名1:a 表名2:b) JTl
37j
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,Ea.ts>
7、说明:在线视图查询(表名1:a )
0qZ{:}`3
select * from (SELECT a,b,c FROM a) T where t.a > 1; t'0r4&\
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 U}7$:hO"dX
select * from table1 where time between time1 and time2 ma?569Z8~0
select a,b,c, from table1 where a not between 数值1 and 数值2 pk(<],0]X
9、说明:in 的使用方法 g:e|
select * from table1 where a [not] in ('值1','值2','值4','值6') 42tD$S5^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #.a4}ya19
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =4+UX*&i?.
11、说明:四表联查问题: Z4bN|\I
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 4$d|}ajH
12、说明:日程安排提前五分钟提醒 d/Fjs0pt
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `;5UlkVZ5
13、说明:一条sql 语句搞定数据库分页 :3{@LOil^
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 Og"50 -
14、说明:前10条记录 ObMsncn
select top 10 * form table1 where 范围 1wqCoDgkp
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.) fy9{W @E3p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) *sB=Ys?
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 qV8;;&8r
(select a from tableA ) except (select a from tableB) except (select a from tableC) eJ$?T7aUf
17、说明:随机取出10条数据 z15(8Y@2]
select top 10 * from tablename order by newid() $9Y2\'w<h6
18、说明:随机选择记录 ANn{*h
select newid() 7^as~5'&-
19、说明:删除重复记录 W"VN2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 44RZk|U1J{
20、说明:列出数据库里所有的表名 mmr>"`5.
select name from sysobjects where type='U' ,LWM}L
21、说明:列出表里的所有的 QRw306
select name from syscolumns where id=object_id('TableName') E9%xSMS8@
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。 {Am\%v\
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 "op1x to
显示结果: kH1l -mxz
type vender pcs ,N<;!6e
电脑 A 1 ~ $!eB/6ty
电脑 A 1 !);}zW!
光盘 B 2 &g.w~KWa
光盘 A 2 t<}'/
)
手机 B 3 ^=E4~22q
手机 C 3 u#la+/
23、说明:初始化表table1 9%kY8#%SV
TRUNCATE TABLE table1 mcS/-DaN?
24、说明:选择从10到15的记录 U|-4*l9Ed
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {eqUEdC
#B)/d?aa'
m{(D*Vuqd
ldanM>5
三、技巧 >sPu*8D40a
1、1=1,1=2的使用,在SQL语句组合时用的较多 tN";o\!}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 2,q^O3F
如: qPH]DabpI
if @strWhere !='' )0fQ(3oOg
begin peR=J7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .Eh~$wm
end 1Qhx$If~
else ;oWh Tj`
begin o9q%=/@,
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ~e,
end (3{'GX2c
我们可以直接写成 =u${2=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #e+%;5\
2、收缩数据库 bN<c5
--重建索引 Nd^9.6,JU
DBCC REINDEX T*-*U/
DBCC INDEXDEFRAG @\u)k
--收缩数据和日志 %jKR\f G
DBCC SHRINKDB @Eqc&v!O
DBCC SHRINKFILE g%1!YvS3v
3、压缩数据库 91mXv Q:u
dbcc shrinkdatabase(dbname) #x)G2T'?
4、转移数据库给新用户以已存在用户权限 V{ra,a*
exec sp_change_users_login 'update_one','newname','oldname' H<X4R
go P}DrUND
5、检查备份集 \C/`?"4w
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 5#$E4k:YV
6、修复数据库 S;i^ucAF
ALTER DATABASE [dvbbs] SET SINGLE_USER A<y3Tc?Q
GO J U}XSb
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK W4|1wd}.t
GO WI[6l6
ALTER DATABASE [dvbbs] SET MULTI_USER 92+({ fgW
GO iDp]lu
7、日志清除 zdU<]ge
SET NOCOUNT ON "MM7qV
DECLARE @LogicalFileName sysname, mK@\6GOMYP
@MaxMinutes INT, "&Q-'L!M'/
@NewSize INT 3vQ?vS|2
USE tablename -- 要操作的数据库名 ItC*[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 H,:Cg:E/^
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `$G7Ia_ $]
@NewSize = 1 -- 你想设定的日志文件的大小(M) o=q
N+-N
-- Setup / initialize R:0Fv9bwS
DECLARE @OriginalSize int qqS-0U2
SELECT @OriginalSize = size i ,4
FROM sysfiles L4
x
WHERE name = @LogicalFileName [q9TTJ@2
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f*2V
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #s(B,`?N
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <W|{zAyv
FROM sysfiles ]rZ"5y
WHERE name = @LogicalFileName uhQ3
CREATE TABLE DummyTrans e`<=&w
(DummyColumn char (8000) not null) vyN=X]p
DECLARE @Counter INT,
AN$}%t"
@StartTime DATETIME, qI:}3b;T
@TruncLog VARCHAR(255) :*1|ERGoay
SELECT @StartTime = GETDATE(), [~f%z(vI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' x%vt$dy*8
DBCC SHRINKFILE (@LogicalFileName, @NewSize) b0m1O.&I_
EXEC (@TruncLog) YAC=V?U-#
-- Wrap the log if necessary. _GI [SzD
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tG^Oj:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Ds&)0Iwf
AND (@OriginalSize * 8 /1024) > @NewSize `(W
V pP?
BEGIN -- Outer loop. pFGdm3pV
SELECT @Counter = 0 7:mM`0g!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ib/&8)Y+J
BEGIN -- update 5p
U(A6RtS
INSERT DummyTrans VALUES ('Fill Log') O0WzDD
DELETE DummyTrans &nZ=w#_
SELECT @Counter = @Counter + 1 F 3,hx
END Ndx.SOj
EXEC (@TruncLog) M\e%GJ0
END .F'Fk=N
SELECT 'Final Size of ' + db_name() + ' LOG is ' + O`OntYwa>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + u2 -%~Rlo
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N%_-5Q)so
FROM sysfiles \hv*`ukF
WHERE name = @LogicalFileName A~h.,<+"
DROP TABLE DummyTrans D
GOc!
SET NOCOUNT OFF 7KuTC%7
8、说明:更改某个表 '#u|RsZ
exec sp_changeobjectowner 'tablename','dbo' DWm$:M4z
9、存储更改全部表 qJ5Y}/r
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch w/h?, L|
@OldOwner as NVARCHAR(128), c 6E@+xU
@NewOwner as NVARCHAR(128) So bK<6
AS -;Cl0O%
DECLARE @Name as NVARCHAR(128) :Oa|&.0l?
DECLARE @Owner as NVARCHAR(128) Ct$e`H!;
DECLARE @OwnerName as NVARCHAR(128) rguC#Xt!4
DECLARE curObject CURSOR FOR #x':qBv#
select 'Name' = name, -.ha\ t0J
'Owner' = user_name(uid) HQQc<7c",
from sysobjects j9x}D;?n
where user_name(uid)=@OldOwner Maf!,/U4
order by name pYceMZ$
OPEN curObject bYgrKz@uK
FETCH NEXT FROM curObject INTO @Name, @Owner E"pq ZP =
WHILE(@@FETCH_STATUS=0) \qNj?;B
BEGIN ,F6i5128{
if @Owner=@OldOwner l')?w]|
begin kX+y2v(2++
set @OwnerName = @OldOwner + '.' + rtrim(@Name) wKXKc\r
exec sp_changeobjectowner @OwnerName, @NewOwner &"K74
end Z3~$"V*ZB{
-- select @name,@NewOwner,@OldOwner -'5:Cq
FETCH NEXT FROM curObject INTO @Name, @Owner f{^C+t{r
END 42ttmN1F
close curObject
Mf/zSQk+
deallocate curObject 0&2TeqsLh)
GO MFiX8zwhx+
10、SQL SERVER中直接循环写入数据 JV(|7Sk
declare @i int qD7#q]
set @i=1 `[VoW2CLH+
while @i<30 3xp%o5K
begin 1ncY"S/VO
insert into test (userid) values(@i) % ]r@vjeyd
set @i=@i+1 xo7H^!_
end d_1w
9FA
小记存储过程中经常用到的本周,本月,本年函数 EoIP#Cnd1
Dateadd(wk,datediff(wk,0,getdate()),-1) "Z& {
Dateadd(wk,datediff(wk,0,getdate()),6) fC&Egy
Dateadd(mm,datediff(mm,0,getdate()),0) {-7];e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +>44'M^Z|(
Dateadd(yy,datediff(yy,0,getdate()),0) 6_^u}me
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Nyow:7p
上面的SQL代码只是一个时间段 HGh`O\f8
Dateadd(wk,datediff(wk,0,getdate()),-1) |XLx6E2F
Dateadd(wk,datediff(wk,0,getdate()),6) ~y$B#.l
就是表示本周时间段. %RdCSQ9~
下面的SQL的条件部分,就是查询时间段在本周范围内的: -9.S?N'T>;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) tm#T8iF
而在存储过程中 NVcL9"ht*@
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %fJ*Ql4M
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) lRZt))3