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。 |`wJ
{-
3PzF^ 8KJ
@*T8>
一、基础 3e;K5qSeo/
1、说明:创建数据库 (|6!pQ7
CREATE DATABASE database-name 7S&O{Q7)
2、说明:删除数据库 v"sU87+
drop database dbname MS|1Q@S9
3、说明:备份sql server s5d[sx
--- 创建 备份数据的 device tUfze9m
USE master odcrP\S
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8fWnKWbbjw
--- 开始 备份 blbzh';0}
BACKUP DATABASE pubs TO testBack 'i/"D8
4、说明:创建新表 nM$-L.dG
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {;UBW7{
根据已有的表创建新表: OH+2)X
A:create table tab_new like tab_old (使用旧表创建新表) z"sv,W
B:create table tab_new as select col1,col2... from tab_old definition only 3@;24X
5、说明:删除新表 aI\>=*HF
drop table tabname ok&v+A
6、说明:增加一个列 .$x822
Alter table tabname add column col type Si#XF[/
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。 _{i-.;K
7、说明:添加主键: Alter table tabname add primary key(col) OJcI0(G
说明:删除主键: Alter table tabname drop primary key(col) g;3<oI/P
8、说明:创建索引:create [unique] index idxname on tabname(col....) &19z|Id
删除索引:drop index idxname ON_GD"
注:索引是不可更改的,想更改必须删除重新建。 kA 4kQ}q
9、说明:创建视图:create view viewname as select statement '_=XfTF
删除视图:drop view viewname !Nhq)i
10、说明:几个简单的基本的sql语句 'aZAWY d
选择:select * from table1 where 范围 97!VH>MX
插入:insert into table1(field1,field2) values(value1,value2) 5i3nz=~o
删除:delete from table1 where 范围 T:j!a{_|
更新:update table1 set field1=value1 where 范围 pHDPj,lu
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uUpOa+t
排序:select * from table1 order by field1,field2 [desc] ~65lDFY/
总数:select count as totalcount from table1 );F
/P0P
求和:select sum(field1) as sumvalue from table1 9VTE?,
平均:select avg(field1) as avgvalue from table1 3o__tU)B
最大:select max(field1) as maxvalue from table1 8\Z/mU*4
最小:select min(field1) as minvalue from table1 O~#OVFJ9=
g5&,l
dI8y}EbE~
f9E.X\"
11、说明:几个高级查询运算词 j7&0ckN&G
MdNV3:[ \
w+ibY
A: UNION 运算符 YC~kq?
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。 p7)b@,
B: EXCEPT 运算符 +Mh 9Jf
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。 Tq.%_/@M<
C: INTERSECT 运算符 iuq%Q\0@w
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。 b{JxTT}03
注:使用运算词的几个查询结果行必须是一致的。 Sh5SOYLz
12、说明:使用外连接 0l %|2}a
A、left outer join: ] yXrD`J!
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。 G Q+g.{c
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 {I_I$x_
B:right outer join: m`ab5<%Gn
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。 (V~PYf%
C:full outer join: |a Ht6F
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。 Wr;?t!
p>]2o\["
&5wM`
二、提升 o[eIwGxZ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) j]_"MMwk$<
法一:select * into b from a where 1<>1 %8GY`T:^
法二:select top 0 * into b from a s%qK<U4@;Q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ut^^,w{o>
insert into b(a, b, c) select d,e,f from b; ViT$]Nv
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) VlFDMw.4.+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 QI2T G,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Bx&wS|-) D
4、说明:子查询(表名1:a 表名2:b) ?_c*(2i&^
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) |[lM2
5、说明:显示文章、提交人和最后回复时间 ddD $ 4+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Z)zmT%t
6、说明:外连接查询(表名1:a 表名2:b) [HhdeLOX
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c gobqS+c
7、说明:在线视图查询(表名1:a ) Z66@@?`
select * from (SELECT a,b,c FROM a) T where t.a > 1; S}*%l)vfR
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 @=[SsS
select * from table1 where time between time1 and time2 ^E8eW
select a,b,c, from table1 where a not between 数值1 and 数值2 ~\m|pxcj
9、说明:in 的使用方法 NLxsxomj
select * from table1 where a [not] in ('值1','值2','值4','值6') $.@)4Nu!_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 jlZW!$Iq
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ot}
E
11、说明:四表联查问题: sj @'C@oK
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 ..... xcYYo'U
12、说明:日程安排提前五分钟提醒 ^m:?6y_uw
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ~m56t5+uw
13、说明:一条sql 语句搞定数据库分页 aTy&"
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 P}QuGy[
14、说明:前10条记录 uB:utg
select top 10 * form table1 where 范围 J5Tl62}
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.) COK7 i^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) u{ .UZTn
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 x~tG[Y2F?
(select a from tableA ) except (select a from tableB) except (select a from tableC) r'q9N
17、说明:随机取出10条数据 ,2%> e"%
select top 10 * from tablename order by newid() )rs);Pl
18、说明:随机选择记录 ~T[m{8uh
select newid() "syf@[tz7
19、说明:删除重复记录 /\KB*dX
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) GxGZxf*(
20、说明:列出数据库里所有的表名 %h%^i
select name from sysobjects where type='U' s^$zOp9
21、说明:列出表里的所有的 <3>Ou(F
select name from syscolumns where id=object_id('TableName') xCV3HnZ
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 =ITMAC\
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type <zK9J?ZQW>
显示结果: oY{r83h{
type vender pcs h&vq}
电脑 A 1 "+ji`{
电脑 A 1 #9Z*.
光盘 B 2 3y?ig2
光盘 A 2 E:&ga}h
手机 B 3 %o+VZEH3
手机 C 3 ;
. c]0
23、说明:初始化表table1 Hdh'!|w
TRUNCATE TABLE table1 .;n<k
24、说明:选择从10到15的记录 T%xB|^lf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc zRJopcE<
:R<n{%~
iCIu]6
zrt8ze=Su
三、技巧 a-,BBM 8|
1、1=1,1=2的使用,在SQL语句组合时用的较多 C/+8lA6NV
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?K/z`E!xhN
如:
xxm1Nog6
if @strWhere !='' 3L4lk8Dd
begin #{l+I(M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere , c/\'k\K)
end _Ucj)Ud k
else !_cT_
WHty
begin *"Ipu"G5?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' dQt*/]{q
end LRv-q{jP;
我们可以直接写成 o=2y`Eq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere !G#3jh:kiY
2、收缩数据库 J+LFzl07q
--重建索引 }9Z?UtS
DBCC REINDEX %
j7lLSusX
DBCC INDEXDEFRAG r
8,6qP[
--收缩数据和日志 EpCUL@+
DBCC SHRINKDB Mnaoh:z
DBCC SHRINKFILE 81/Bn!
3、压缩数据库 2`l$uEI3oJ
dbcc shrinkdatabase(dbname) F#Oqa^$(
4、转移数据库给新用户以已存在用户权限 1HBch]J
exec sp_change_users_login 'update_one','newname','oldname' '@Y@H,
go 5_nkN`x
5、检查备份集 /cr.}D2O
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' g R(*lXm5w
6、修复数据库 M,PZ|=V6a
ALTER DATABASE [dvbbs] SET SINGLE_USER Vcl"qz@Fj
GO Fp06a!7<
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >b |l6#%
GO ){")RrD(
ALTER DATABASE [dvbbs] SET MULTI_USER y8wOJZ<K
GO ^Yn{Vi2.
7、日志清除 h8O[xca/~
SET NOCOUNT ON {JzX`Z30l
DECLARE @LogicalFileName sysname, z$`=7 afp
@MaxMinutes INT, s&M6DFlA
@NewSize INT HlY4%M5q/
USE tablename -- 要操作的数据库名 >0 i?}
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Tfgx>2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }
CJQC
@NewSize = 1 -- 你想设定的日志文件的大小(M) d"nE+pgE
-- Setup / initialize z_<
7T4
DECLARE @OriginalSize int w-|i8%X
SELECT @OriginalSize = size aIZ@5w"7
FROM sysfiles z8= Gc$w!
WHERE name = @LogicalFileName &|26x
>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + U\
y?P:yy
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L$@^EENS
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6$b"tdP
FROM sysfiles p(~>u'c
WHERE name = @LogicalFileName oyJ/Oe
{
CREATE TABLE DummyTrans rGRxofi.
(DummyColumn char (8000) not null) GOa](oD}
DECLARE @Counter INT, %dS7u$Rnh
@StartTime DATETIME, l0u6nGkh
@TruncLog VARCHAR(255) F1)Q#ThF\
SELECT @StartTime = GETDATE(), ^,b*.6t
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' l@<^V N@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) B.K"1o
EXEC (@TruncLog) ]ODC+q1
-- Wrap the log if necessary. Wb!%_1dER
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =6j
5,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [FC7+
Ey^
AND (@OriginalSize * 8 /1024) > @NewSize 1p23&\\~
BEGIN -- Outer loop. #d*mG =
SELECT @Counter = 0 hn.9j"
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) djPr 4Nog
BEGIN -- update iX.=8~3
INSERT DummyTrans VALUES ('Fill Log') 2sy{
DELETE DummyTrans zY\v|l<T
SELECT @Counter = @Counter + 1 Zo;@StN3}T
END Q9 kKk
EXEC (@TruncLog) )dJM
END e&7GW9FSg
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ).N }x^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + C\.? 3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \Q*3/_}G
FROM sysfiles t_3)}
WHERE name = @LogicalFileName =@binTC4
DROP TABLE DummyTrans U-3KuR+0
SET NOCOUNT OFF T6Ue\Sp'
8、说明:更改某个表 _xAdvr' W
exec sp_changeobjectowner 'tablename','dbo' mv SNKS
9、存储更改全部表 KHcfP7
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^P:9iu)+]~
@OldOwner as NVARCHAR(128), |vTirZP
@NewOwner as NVARCHAR(128) .-`7Av+7
AS K,|Gtaa~
DECLARE @Name as NVARCHAR(128) s3_i5,y
DECLARE @Owner as NVARCHAR(128) Z=R>7~H
DECLARE @OwnerName as NVARCHAR(128) Trbgg
DECLARE curObject CURSOR FOR =d7 lrx+z
select 'Name' = name, 11X-X
'Owner' = user_name(uid) y$*Tbzp
from sysobjects &>@nW!n
u
where user_name(uid)=@OldOwner @6
gA4h
order by name N^h,[
OPEN curObject 0$}+tq+
FETCH NEXT FROM curObject INTO @Name, @Owner uc=-+*D'I
WHILE(@@FETCH_STATUS=0) 0l.+yr}PE
BEGIN W5_t/_EWD
if @Owner=@OldOwner 4'Vuhqk
begin Nh]eZ3O
set @OwnerName = @OldOwner + '.' + rtrim(@Name) u~1[nH:
exec sp_changeobjectowner @OwnerName, @NewOwner -Qiay/tlu
end bW3e*O$V
-- select @name,@NewOwner,@OldOwner
HHWB_QaL
FETCH NEXT FROM curObject INTO @Name, @Owner ;'}1
END n|SsV
close curObject @w,-T@nAW
deallocate curObject vsqfvx
GO "]*0)h_
10、SQL SERVER中直接循环写入数据 &UbNp8h
declare @i int M `Y~IG}
set @i=1 WSi Utf|g
while @i<30
@5acTYQ
begin 9!_`HE+(XJ
insert into test (userid) values(@i) Z\(+awv
set @i=@i+1 Q++lgVh)E
end R7ZxS
小记存储过程中经常用到的本周,本月,本年函数 !(uyqplTk
Dateadd(wk,datediff(wk,0,getdate()),-1) -7'>Rw
Dateadd(wk,datediff(wk,0,getdate()),6) JT[|l-\zo
Dateadd(mm,datediff(mm,0,getdate()),0) '<>pz<c
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,U],Wu)
Dateadd(yy,datediff(yy,0,getdate()),0) 3UslVj1u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1f~unb\Gg
上面的SQL代码只是一个时间段 o`M7:8G
Dateadd(wk,datediff(wk,0,getdate()),-1) i)+@'!6
Dateadd(wk,datediff(wk,0,getdate()),6) ]*%0CDY6`N
就是表示本周时间段. wcsUb9(
下面的SQL的条件部分,就是查询时间段在本周范围内的: #
T$^{/J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Ls5|4%+&
而在存储过程中 3)atqM)i
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %:N5k+}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~-A5h(