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。 KuE
2a,E4
9(ANhG
C37KvLQ
一、基础 fLct!H3
1、说明:创建数据库 f=g/_R2$xN
CREATE DATABASE database-name ^<[oKi;>
2、说明:删除数据库 u|O5ZV-cd
drop database dbname b\dBt#mB!
3、说明:备份sql server Qighvei
--- 创建 备份数据的 device ,R ]]]7)+
USE master X: @nROL^7
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'S E%9
--- 开始 备份 1ciP+->$
BACKUP DATABASE pubs TO testBack w*$nG$
4、说明:创建新表 sqj8c)6
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )uZ<?bkQ
根据已有的表创建新表: h^?[:XBeav
A:create table tab_new like tab_old (使用旧表创建新表) u{tjB/K&
B:create table tab_new as select col1,col2... from tab_old definition only .2[>SI
5、说明:删除新表 `!>zYcmT
drop table tabname :=UeYm
@
6、说明:增加一个列 Lt|k}p@]
Alter table tabname add column col type UH.M)br
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。 !|!:MYn
7、说明:添加主键: Alter table tabname add primary key(col) }oj$w?Ex
说明:删除主键: Alter table tabname drop primary key(col) .+|G`*1<i
8、说明:创建索引:create [unique] index idxname on tabname(col....) &6r".\;^
删除索引:drop index idxname H_vOZ0
注:索引是不可更改的,想更改必须删除重新建。 p\b:uy6#
9、说明:创建视图:create view viewname as select statement #CHsH{d
删除视图:drop view viewname u23^* -
10、说明:几个简单的基本的sql语句 6>SP5|GG
选择:select * from table1 where 范围 lmQ!q>N
插入:insert into table1(field1,field2) values(value1,value2)
VG q'
删除:delete from table1 where 范围 y<8)mw
更新:update table1 set field1=value1 where 范围 L8/o9N1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! j}#48{
排序:select * from table1 order by field1,field2 [desc] 3Ki`W!C
总数:select count as totalcount from table1 i1\xZ<|0
求和:select sum(field1) as sumvalue from table1 |Tf}8e
平均:select avg(field1) as avgvalue from table1 Yf7n0Etd,
最大:select max(field1) as maxvalue from table1 T"dX)~E;
最小:select min(field1) as minvalue from table1 +:mj]`=
bX=ht^e[
eIg '
!8h?
)=[K$>0k
11、说明:几个高级查询运算词 (s,Nq~O
bx!Sy0PUJ
ZRsDn
A: UNION 运算符 $9M>B<]
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 6V*@
{
B: EXCEPT 运算符 4US8B=jk
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 V0c*M>V
C: INTERSECT 运算符 3)EslBA7i
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 v^HDR 3I
注:使用运算词的几个查询结果行必须是一致的。 ?K|PM<A
12、说明:使用外连接 K>w}(td
A、left outer join: ,#`gwtFG
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 D>VI{p
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2JUX29rER
B:right outer join: qs\
&C
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 #:DDx5%x<b
C:full outer join: .G?7t6A
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 fn&gM\<-+(
1;080|,s
xXp\U'Ad~~
二、提升 * j:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
&5O
法一:select * into b from a where 1<>1 hy3[MOD$G
法二:select top 0 * into b from a Lk4&&5q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rcOpOoU|
insert into b(a, b, c) select d,e,f from b; JrOp-ug
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) f(|qE(
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /^P^K
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ;!Ojb
4、说明:子查询(表名1:a 表名2:b) T,`'qZ>
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) MDGcK/$')f
5、说明:显示文章、提交人和最后回复时间 --Dw8FR9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0A9x9l9Wd
6、说明:外连接查询(表名1:a 表名2:b) "n7rbh3VW
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c OzX\s=
7、说明:在线视图查询(表名1:a ) `P)1RTVx
select * from (SELECT a,b,c FROM a) T where t.a > 1; w`c9_V
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 p! zC
select * from table1 where time between time1 and time2 D$YAi%*H
select a,b,c, from table1 where a not between 数值1 and 数值2 HC?yodp^
9、说明:in 的使用方法 h34|v=8d
select * from table1 where a [not] in ('值1','值2','值4','值6') /-8v]nRB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 DN&ZRA
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5R{
{FD`h
11、说明:四表联查问题: >Y1?`
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 ..... 7h&$^
12、说明:日程安排提前五分钟提醒 818</b<yn
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )j',e$m
13、说明:一条sql 语句搞定数据库分页 i>7f9D7
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 `$nMTx]Y
14、说明:前10条记录 Ys+Dw-
select top 10 * form table1 where 范围 c<y.Y0
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ~Rs|W;
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 9hmCvQgtf
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ^G~W}z?-
(select a from tableA ) except (select a from tableB) except (select a from tableC) % 95:yyH 0
17、说明:随机取出10条数据 3wX{U8mrg
select top 10 * from tablename order by newid() ,B5Ptf#
18、说明:随机选择记录 0{BPT>'
select newid() ^ B=x-G.
19、说明:删除重复记录 v"F.<Q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) dt',)i8D
20、说明:列出数据库里所有的表名 one^XYy1%
select name from sysobjects where type='U' _B8e1an
21、说明:列出表里的所有的 2t<
dCw
select name from syscolumns where id=object_id('TableName') f"k?Ix\
e
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 lqF{Y<l
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type o~NeS|a
显示结果: l(v$+
type vender pcs l#\z3"b
电脑 A 1 !6@xX08z
电脑 A 1 h$f/NSct2
光盘 B 2 wf=#w}f
光盘 A 2 f8#WT$Ewy
手机 B 3 YRG+I GX
手机 C 3 L`R,4mI.W
23、说明:初始化表table1 CbQ@l@d]
TRUNCATE TABLE table1 bv\V>s
24、说明:选择从10到15的记录 >QE^KtZ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 95T%n{rz
pnxjuDN7}x
YQ,IdWav
p0qQ(
三、技巧 L}XEROTR
1、1=1,1=2的使用,在SQL语句组合时用的较多 |Mo# +{~c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, w_KGn17
如: _a+0LTo".
if @strWhere !='' Jtd@8fVi
begin ?Ih24>:D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _xl#1>G^J
end C:
kl/9M@
else `eND3c
begin 6lT1X)
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l
YH={jJ
end UciWrwE
我们可以直接写成
CV]PCq!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere `DG6ollp{
2、收缩数据库 8kW9.
--重建索引 D8m?`^Zz
DBCC REINDEX smIZ:L%
DBCC INDEXDEFRAG ;FMK>%Zq
--收缩数据和日志 ZNOoyWYi5
DBCC SHRINKDB $C9<{zX
DBCC SHRINKFILE Co[[6pt~
3、压缩数据库 R:E6E@T
dbcc shrinkdatabase(dbname) 3 [SN[faS
4、转移数据库给新用户以已存在用户权限 ~-']Q0Z
exec sp_change_users_login 'update_one','newname','oldname' iV'-j,-i
go **! lV]/
5、检查备份集 +GP"9S2%R
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' X-:Ni_O\ty
6、修复数据库 AN^ ,
ALTER DATABASE [dvbbs] SET SINGLE_USER ])m",8d&T
GO Ef%8+_
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK iN`/pW/JE
GO eb9qg.9Z
ALTER DATABASE [dvbbs] SET MULTI_USER n 8AND0a1C
GO u%XFFt5
7、日志清除 *9j9=N?
SET NOCOUNT ON *uA?}XEfi
DECLARE @LogicalFileName sysname, <e/O"6='Z
@MaxMinutes INT, AU87cqq
@NewSize INT II>X6
USE tablename -- 要操作的数据库名 Y0s^9?*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1Y}gki^F
@MaxMinutes = 10, -- Limit on time allowed to wrap log. A'[A!NL%
@NewSize = 1 -- 你想设定的日志文件的大小(M) :vurU$\
-- Setup / initialize ^3=8*Xr
DECLARE @OriginalSize int ;2L=WR%
SELECT @OriginalSize = size )@R:$l86
FROM sysfiles }^`{YD
WHERE name = @LogicalFileName Zr}`W\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + pxI*vgfN7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (g7nMrE$j
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' JGj_{|=:
FROM sysfiles <(BA ws(X
WHERE name = @LogicalFileName
~{^AP
CREATE TABLE DummyTrans ei\X/Z*q%P
(DummyColumn char (8000) not null) Ql&P1|&
DECLARE @Counter INT, <>j,Q
@StartTime DATETIME, *zX<`E
@TruncLog VARCHAR(255) =_^g]?5i
SELECT @StartTime = GETDATE(), X){F^1CT{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' et9c<'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) hp,T(D|
EXEC (@TruncLog) HoRLy*nU
-- Wrap the log if necessary. 2mU}"gf[
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _xUhDu%
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]"/ *7NM
AND (@OriginalSize * 8 /1024) > @NewSize ,l0s(Cg
BEGIN -- Outer loop. GExG1n-
SELECT @Counter = 0 ,P auP~L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) NA/+bgyuT>
BEGIN -- update {F@;45)o
INSERT DummyTrans VALUES ('Fill Log') zh/+1
DELETE DummyTrans Bj@&c>
SELECT @Counter = @Counter + 1 QO#ZQ~
END l\$C)q6O
EXEC (@TruncLog) Y Nq<%i!>
END &v 5yo}s
SELECT 'Final Size of ' + db_name() + ' LOG is ' + y:2o-SJn
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 5)T{iPU%X
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^+GN8LUs
FROM sysfiles #(
kT
WHERE name = @LogicalFileName #e8CuS
DROP TABLE DummyTrans
K[?wP>s
SET NOCOUNT OFF ?[m5|ty#
8、说明:更改某个表 Llk`
exec sp_changeobjectowner 'tablename','dbo' HnY: gu
9、存储更改全部表 xFpJ#S&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^xqh!
@OldOwner as NVARCHAR(128), c#Y9L+O
@NewOwner as NVARCHAR(128) u{H_q&1
AS |ZZ3Qr+%S
DECLARE @Name as NVARCHAR(128) &Q&$J )0
DECLARE @Owner as NVARCHAR(128) )9<)mV*EB(
DECLARE @OwnerName as NVARCHAR(128) "UAW
DECLARE curObject CURSOR FOR IloHU6h'
select 'Name' = name, A@DIq/^xM
'Owner' = user_name(uid) Qz$.t>@V=
from sysobjects UI8M<
where user_name(uid)=@OldOwner uk\GAm@O
order by name niA{L:4
OPEN curObject 7s.sbP~
FETCH NEXT FROM curObject INTO @Name, @Owner gl!3pTC
WHILE(@@FETCH_STATUS=0) l;|1C[V
BEGIN Q2fa]*Z5
if @Owner=@OldOwner 5@v!wms
begin }'@*Ol j
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~?L. n:wu
exec sp_changeobjectowner @OwnerName, @NewOwner i,)kI
end w\@Anwj#L
-- select @name,@NewOwner,@OldOwner ^3r2Q?d\
FETCH NEXT FROM curObject INTO @Name, @Owner z ,ledTl
END l|uN-{w
close curObject MT&i5!Z
deallocate curObject SQz>e
GO ]I}'
[D
10、SQL SERVER中直接循环写入数据 L3kms6ch
declare @i int 99ZQlX
set @i=1 RKBtwZx>f
while @i<30 sF<4uy
begin zF{z_c#3@
insert into test (userid) values(@i) i\t4TdEx(
set @i=@i+1 nKHyq\
end ?VzST }
小记存储过程中经常用到的本周,本月,本年函数 z!F?#L5
Dateadd(wk,datediff(wk,0,getdate()),-1) t;4{l`dk
Dateadd(wk,datediff(wk,0,getdate()),6) |bBYJ
Dateadd(mm,datediff(mm,0,getdate()),0) ZAiQofQ:2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]0O pd9
Dateadd(yy,datediff(yy,0,getdate()),0) 0#yo\McZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 35,SP R
上面的SQL代码只是一个时间段 a]ftE\99
Dateadd(wk,datediff(wk,0,getdate()),-1) "urQUpF
Dateadd(wk,datediff(wk,0,getdate()),6) tZ6KU11O
就是表示本周时间段. ^c!Hur6)
下面的SQL的条件部分,就是查询时间段在本周范围内的: (>Tu~Vo
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) n\P{Mc
而在存储过程中 oR5`-
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "1l d4/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 7Y$p3]0e+