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。 T
-p~8=I
Y|!m
"wR1=&gk
一、基础 8l l}"
1、说明:创建数据库 q o6~)Aws
CREATE DATABASE database-name &_$0lIDQ
2、说明:删除数据库 r_hs_n!6
drop database dbname >ZwDcuJ~Lz
3、说明:备份sql server *djVOC
--- 创建 备份数据的 device )^`V{iD
USE master G]n_RP$G
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Al1}Ir
--- 开始 备份 tbXl5x0
BACKUP DATABASE pubs TO testBack _)S['[
4、说明:创建新表 ()Q#@?c~
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %M,^)lRP
根据已有的表创建新表: 6z5wFzJv?q
A:create table tab_new like tab_old (使用旧表创建新表) F};T<#
B:create table tab_new as select col1,col2... from tab_old definition only P84=.*>
5、说明:删除新表 %-KgR
drop table tabname w `nm}4M
6、说明:增加一个列 T'ei>]y]
Alter table tabname add column col type TD sjNFe3
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。 [XhG7Ly
7、说明:添加主键: Alter table tabname add primary key(col) 60G(jO14
说明:删除主键: Alter table tabname drop primary key(col) cTBUj
8、说明:创建索引:create [unique] index idxname on tabname(col....) tR\cS)
删除索引:drop index idxname ZmDM=qN
注:索引是不可更改的,想更改必须删除重新建。 D(WdI
9、说明:创建视图:create view viewname as select statement 9~J#> C0}
删除视图:drop view viewname %Jji<M]
10、说明:几个简单的基本的sql语句 fuU
3?SG
选择:select * from table1 where 范围 Z*+y?5+L"P
插入:insert into table1(field1,field2) values(value1,value2) Z<iK(?@O
删除:delete from table1 where 范围 .L~
NX/V
更新:update table1 set field1=value1 where 范围 dsn(h5,Q'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ,<BV5~T.|
排序:select * from table1 order by field1,field2 [desc] -W{ !`<8D
总数:select count as totalcount from table1 6j Rewj
求和:select sum(field1) as sumvalue from table1 q 2P_37
平均:select avg(field1) as avgvalue from table1 PJO.^OsM
最大:select max(field1) as maxvalue from table1 tlM >=s'T
最小:select min(field1) as minvalue from table1 TkR#Kzv380
zZW5M^z8
0g2rajS
\UP=pT@
11、说明:几个高级查询运算词 2fgYcQ8`
Zb7%$1)L~
p}Um+I=1
A: UNION 运算符 H;seT XL
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Qv<p$Up6
B: EXCEPT 运算符 `MHixQ;j
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。 Q@uWh:
C: INTERSECT 运算符 Ob/i_
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。 R7 rO7M!
注:使用运算词的几个查询结果行必须是一致的。 =M6{{lI/
12、说明:使用外连接 "A*;V
A、left outer join: {"2Hv;x
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。 Mh2Zj
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 TBIr^n>Z<k
B:right outer join: DX^8w?t
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。 Xf[;^?]X
C:full outer join: r PTfwhs
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。 $Xh5N3
0 ;].q*|#
<MKXFV
二、提升 !>N+a3
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) kC ALJRf~d
法一:select * into b from a where 1<>1 azzG
法二:select top 0 * into b from a V|TD+7.`QB
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jNI9 .45y
insert into b(a, b, c) select d,e,f from b; w9StW94p
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) +k
h
Tl:
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P:WxhO/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 9 ^8_^F
4、说明:子查询(表名1:a 表名2:b) ->*~e~T
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) ]T{v~]7:{
5、说明:显示文章、提交人和最后回复时间 =
c1>ja
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2*< PmKI
6、说明:外连接查询(表名1:a 表名2:b) dV{mmHL
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H&
$M/`
7、说明:在线视图查询(表名1:a ) 6HPuCP
select * from (SELECT a,b,c FROM a) T where t.a > 1; LLFQ5py{
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 * H~=dPC
select * from table1 where time between time1 and time2 [%P[ x]-
select a,b,c, from table1 where a not between 数值1 and 数值2 f1S%p
9、说明:in 的使用方法 B6j/"x6N15
select * from table1 where a [not] in ('值1','值2','值4','值6') p({Lp}'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 `H q*l"8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) j"jQiL_*
11、说明:四表联查问题: |S~$IFN4
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 ..... gb4$W@N7V
12、说明:日程安排提前五分钟提醒 M?=I{}!@Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 P+y XC^ ,
13、说明:一条sql 语句搞定数据库分页 \mTi@T!&
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 }]M'f:%b
14、说明:前10条记录 BnfuI
select top 10 * form table1 where 范围 %O!TS_~9
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) kT]jJbb"
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ]0O3kiVQ
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 !xBJJ/K+|
(select a from tableA ) except (select a from tableB) except (select a from tableC) Y78DYbU.
17、说明:随机取出10条数据 j;qV+Rq]t
select top 10 * from tablename order by newid() 7PuYrJ
18、说明:随机选择记录 ESk:$`P
select newid() $E!f@L
19、说明:删除重复记录 LqO=wK~
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) c^cr_i
20、说明:列出数据库里所有的表名 `Z#':0Z
select name from sysobjects where type='U' k'*vG6!
21、说明:列出表里的所有的 ri-D#F)}
select name from syscolumns where id=object_id('TableName') I5Ty@J#
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。 pN_%>v"o
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 Pe-rwM
显示结果: 8_ascvs5
type vender pcs j/q&qrlL
电脑 A 1 ~W={"n?=
电脑 A 1 `DE_<l
光盘 B 2 +]( #!}oH
光盘 A 2 `mI5Z*]-
手机 B 3 8GRB6-.h
手机 C 3 \3]O?'
23、说明:初始化表table1 $BT[fJ'k
TRUNCATE TABLE table1 GIT"J}b}
24、说明:选择从10到15的记录 ]jPP]Z:y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {2QP6X sJ
[$uKI,l
B'mUDW8\D
:>0,MO.^~K
三、技巧 MBLDxsZ-
1、1=1,1=2的使用,在SQL语句组合时用的较多 6tjV^sjs
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }#;.b'`
如: H+5+;`;
if @strWhere !='' Q1{9>NI
begin FA\U4l-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _>aP5g?Ep
end ~{);Ab.9+
else -E3cS
begin ]5K(}95&'
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r&Qa;-4Pl
end #d<|_
我们可以直接写成 |H]0pbC)w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 1G67#L)USq
2、收缩数据库 #0Uz1[
--重建索引 o2hk!#5[4
DBCC REINDEX [c lwmx
DBCC INDEXDEFRAG A|]#b?-
--收缩数据和日志 'x<oILOG
DBCC SHRINKDB 2`%a[t@M.
DBCC SHRINKFILE
hSXJDT2
3、压缩数据库 a1Q%Gn@R
dbcc shrinkdatabase(dbname) >qOj^WO~
4、转移数据库给新用户以已存在用户权限 w (z=xO
exec sp_change_users_login 'update_one','newname','oldname' (+cZP&o
go BX6kn/i
5、检查备份集 \t/0Yh-'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e*}GQ
6、修复数据库 W'f"kM
ALTER DATABASE [dvbbs] SET SINGLE_USER hF5T9^8
GO {~j/sto-:
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ww\ WuaY
GO {IvA 5^
ALTER DATABASE [dvbbs] SET MULTI_USER |Ldvfd
GO qX; F+~
7、日志清除 l(-"rE
SET NOCOUNT ON `@WJ_-$#
DECLARE @LogicalFileName sysname, Y"r728T`K
@MaxMinutes INT, z]C=nXbk
@NewSize INT 3:8p="$F
USE tablename -- 要操作的数据库名 >p0,]-.J,r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 WC37=8mA
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <%`Rku
@NewSize = 1 -- 你想设定的日志文件的大小(M) :<k
(y?GB
-- Setup / initialize nHH
FHnFf
DECLARE @OriginalSize int 9$U4x|n
SELECT @OriginalSize = size ggitUQ+t;G
FROM sysfiles Y)$%-'=b+
WHERE name = @LogicalFileName Q$ Dx:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + E/wxX#]\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + FC6~V6R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' XJKns
FROM sysfiles NI.ROk1{+4
WHERE name = @LogicalFileName JZ*.;}"
CREATE TABLE DummyTrans ;UUgqX#
(DummyColumn char (8000) not null) sWMln:=
DECLARE @Counter INT, PB.'huu
@StartTime DATETIME, fH?A.JP=a
@TruncLog VARCHAR(255) HB$?}V
SELECT @StartTime = GETDATE(), 12hD*,A5j
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' XGbpH<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4\p%|G^hU
EXEC (@TruncLog) mk^,{D
-- Wrap the log if necessary. dKC*QHU
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7:Rt) EE2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <1Sj_HCT
AND (@OriginalSize * 8 /1024) > @NewSize /988K-5k
BEGIN -- Outer loop. '6e4rn{
SELECT @Counter = 0 Ycq )$7p
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 98O]tL+k/u
BEGIN -- update GCiG50Z=
INSERT DummyTrans VALUES ('Fill Log') u*W! !(P/
DELETE DummyTrans zJl;|E".
SELECT @Counter = @Counter + 1 ,EVPnH[F~
END 2<p@G#(
EXEC (@TruncLog) :dRC$?f4
END `Mbs6AJ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + WiB~sIp
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + d!}oS<6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' XEagN:
FROM sysfiles x-ue1
WHERE name = @LogicalFileName jpS$5Ct
DROP TABLE DummyTrans ]];pWlo!
SET NOCOUNT OFF frDMFEXXP
8、说明:更改某个表 <y~Ba@1u
exec sp_changeobjectowner 'tablename','dbo' :).NA
]
9、存储更改全部表 ,Wu$@jD/]
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ceD6q~)
@OldOwner as NVARCHAR(128), 'W4v>0
@NewOwner as NVARCHAR(128) }Y BuS3{
AS -sZ'<(3
DECLARE @Name as NVARCHAR(128) Fw{#4
DECLARE @Owner as NVARCHAR(128) p~=z)7%e'
DECLARE @OwnerName as NVARCHAR(128) ov H'_'
DECLARE curObject CURSOR FOR s]0 J'UN
select 'Name' = name, mCk_c
'Owner' = user_name(uid) @ <2y+_e
from sysobjects rPyjr(I"_
where user_name(uid)=@OldOwner iM;Btv[|
order by name GYiL}itD=3
OPEN curObject 3!/J!X3L
FETCH NEXT FROM curObject INTO @Name, @Owner $d])>4eQ
WHILE(@@FETCH_STATUS=0) 1%R${Qhr
BEGIN D.%%D%AdB
if @Owner=@OldOwner &!O?h/&X3
begin ZWGX*F#}P
set @OwnerName = @OldOwner + '.' + rtrim(@Name) MN5}}@
exec sp_changeobjectowner @OwnerName, @NewOwner k\;D;e{
end wbcip8<t
-- select @name,@NewOwner,@OldOwner n'{jc6&|
FETCH NEXT FROM curObject INTO @Name, @Owner Mp!1xx
END aXQAm$/
>
close curObject '0)`.
deallocate curObject 3)LS#=
GO a9.255
10、SQL SERVER中直接循环写入数据 [g<gu~
declare @i int ;<''oY
set @i=1 rP2h9Cb
while @i<30 X[H .t$w5A
begin 7-n HPDp'
insert into test (userid) values(@i) V9}\0joM
set @i=@i+1 eq8faC5
end km5gO|V>m
小记存储过程中经常用到的本周,本月,本年函数 ]3,
Dateadd(wk,datediff(wk,0,getdate()),-1) y=f.;
Dateadd(wk,datediff(wk,0,getdate()),6) a73VDQr I
Dateadd(mm,datediff(mm,0,getdate()),0) .m8l\h^3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) KnA BFH
Dateadd(yy,datediff(yy,0,getdate()),0) C;/ONF
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Qt{V&Z7
上面的SQL代码只是一个时间段 `AvK8Wh<+
Dateadd(wk,datediff(wk,0,getdate()),-1) 5
-|7I7(G$
Dateadd(wk,datediff(wk,0,getdate()),6) nvLdgu4P>
就是表示本周时间段. <pa-C2Ky
下面的SQL的条件部分,就是查询时间段在本周范围内的: d}Guj/cx,
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -AD`(b7q
而在存储过程中 '%ZKvZ-
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _Li.}g@Bd
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) He4HIZ