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。 2NF#mWZ(s
`aL4YH-v
iza.' Mm~
一、基础 FTh/1"a
1、说明:创建数据库 /t04}+,e^
CREATE DATABASE database-name YR.f`-<Z
2、说明:删除数据库 Mb+CtI_'
drop database dbname ]Z>zf]<
3、说明:备份sql server :@,UPc-+
--- 创建 备份数据的 device ui&^ m,
USE master )QB9zl:
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ogJ>`0 +J
--- 开始 备份 72sBx3 ;
BACKUP DATABASE pubs TO testBack t+aE*Q
4、说明:创建新表 Fv3:J~Yf
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L{u1_
根据已有的表创建新表: "v+%F
A:create table tab_new like tab_old (使用旧表创建新表) !}J19]\
B:create table tab_new as select col1,col2... from tab_old definition only 84c[ Z
5、说明:删除新表 }/VSIS@Z
drop table tabname M(.]?+
6、说明:增加一个列 R]y9>5 'U
Alter table tabname add column col type 89fl\18%
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。 v]m#+E
7、说明:添加主键: Alter table tabname add primary key(col) (h27SLYm
说明:删除主键: Alter table tabname drop primary key(col) t_iZ\_8
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7VA6J-T
删除索引:drop index idxname rm!.J0
X
注:索引是不可更改的,想更改必须删除重新建。 9|2LuHQu+
9、说明:创建视图:create view viewname as select statement ~c'R7E&Bfa
删除视图:drop view viewname A[ N>T\
10、说明:几个简单的基本的sql语句 F
<.} q|b
选择:select * from table1 where 范围 m@y_Wt
插入:insert into table1(field1,field2) values(value1,value2) .KxE>lJbqM
删除:delete from table1 where 范围 sX#7;,Ft7
更新:update table1 set field1=value1 where 范围 % ^&D,
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! C72btS
排序:select * from table1 order by field1,field2 [desc] P"k,[ZQ
总数:select count as totalcount from table1 1#jvr_ ga
求和:select sum(field1) as sumvalue from table1 Ts3(,Y
平均:select avg(field1) as avgvalue from table1 qR8 BS4q_p
最大:select max(field1) as maxvalue from table1 33w(Pw
最小:select min(field1) as minvalue from table1 eo'C)j# U
Eq'oy~.oV
!Nno@SP@
fc9gi4y9
11、说明:几个高级查询运算词 ]]_H|tO
{-,^3PI\
@-BgPDi.Z
A: UNION 运算符 f2FGod<CzN
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。 ,E8~^\HV
B: EXCEPT 运算符 <P<^,aC/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。 E3E$_<^
C: INTERSECT 运算符 Lz;E/a}s
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。
g<PdiVp+
注:使用运算词的几个查询结果行必须是一致的。 P8;f^3V(+/
12、说明:使用外连接 ot.R Gpg%
A、left outer join: :]-? l4(%
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。 AV?<D.<
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 }S>:!9f
B:right outer join: z,/y2H2
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。 M^~
C:full outer join: l%9nA.M'
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。 b}jLI_R{
V39)[FH}
^1NtvQe@Y\
二、提升 |cq%eN
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0Z>oiBr4
法一:select * into b from a where 1<>1 (r )fx
法二:select top 0 * into b from a cRC)99HP
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >zWVM1\\j
insert into b(a, b, c) select d,e,f from b; 9TILrK
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) "ktC1y1
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 *oz=k
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0!,)7
4、说明:子查询(表名1:a 表名2:b) .j 0]hn]
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) R7!^ M
5、说明:显示文章、提交人和最后回复时间 rCO:39L-
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "rIBy
6、说明:外连接查询(表名1:a 表名2:b) o'nrLI(t
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =AJ I3'x
7、说明:在线视图查询(表名1:a ) 2-M]!x)
select * from (SELECT a,b,c FROM a) T where t.a > 1; JPT VZ
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 AAt<{
select * from table1 where time between time1 and time2 ld*RL:G
select a,b,c, from table1 where a not between 数值1 and 数值2 Rd.[8#7VE
9、说明:in 的使用方法 !T3Esv
select * from table1 where a [not] in ('值1','值2','值4','值6') g_w4}!|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 s%~p?_P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) U[8Cg
11、说明:四表联查问题: ()+;KF8
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 ..... 5-pz/%,
12、说明:日程安排提前五分钟提醒 er0ClvB
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n"{oj7E0a
13、说明:一条sql 语句搞定数据库分页 :}18G}B
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 U%na^Wu
14、说明:前10条记录 [{B1~D-
select top 10 * form table1 where 范围 q3E_.{t
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.) kV Z5>D$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ywV8s|o
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 c/57_fOK
(select a from tableA ) except (select a from tableB) except (select a from tableC) P'6(HT>F?
17、说明:随机取出10条数据 !S',V&Yb
select top 10 * from tablename order by newid() 'E,Bl]8C5
18、说明:随机选择记录 `N"fsE ma
select newid() tEl4 !vA
19、说明:删除重复记录 lYu1m
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ;DKwv}
20、说明:列出数据库里所有的表名 'yM )>]u"
select name from sysobjects where type='U' mckrR$>
21、说明:列出表里的所有的 8}W06k>)%
select name from syscolumns where id=object_id('TableName') :1wMGk
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。 ?y{C"w!
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 s:/.:e_PU
显示结果: , eZL&n
type vender pcs @kKmkVhu*
电脑 A 1 ]-aeoa#
电脑 A 1 oa?eK
光盘 B 2 $V)LGu2(m
光盘 A 2 [y T4n.f
手机 B 3 bMD'teJ
手机 C 3 VQvl,'z
23、说明:初始化表table1 >9g` 9hB
TRUNCATE TABLE table1 pTK|u!fs
24、说明:选择从10到15的记录 5yQv(<~*G
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc , &HZvU&
^"%SHs
[@= [<
_r
r\"O8\
三、技巧 RfwTqw4@
1、1=1,1=2的使用,在SQL语句组合时用的较多 9Yowz]')
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `8TM<az-L
如: $E4W{ad2jW
if @strWhere !='' %6"b<
MAO
begin 1a90S*M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R6Cm:4m}I
end ^F~e?^s
else [,a O*7N
begin UG>OL2m>5
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' |Tz4 xTK
end q$`:/ ehw
我们可以直接写成 !DCJ2h%E[_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m=S[Y^tR
2、收缩数据库 u
hP0Zwn
--重建索引 HJ5m5':a
DBCC REINDEX lq_W;L
DBCC INDEXDEFRAG T}[W')[s
--收缩数据和日志 As (C8C<
DBCC SHRINKDB Hk\+;'PrN
DBCC SHRINKFILE r<O^uz?Di
3、压缩数据库 H+3I[`v
dbcc shrinkdatabase(dbname) <'
%g $"
4、转移数据库给新用户以已存在用户权限 *ftJ(
exec sp_change_users_login 'update_one','newname','oldname' *<U&DOYV:
go EBM\p+x&
5、检查备份集 (`18W1f5W
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' c`X'Q)c&K
6、修复数据库 z>i D
ALTER DATABASE [dvbbs] SET SINGLE_USER x[}e1sXXs
GO uPV,-rm[F_
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $_Qo
GO Oyq<y~}
ALTER DATABASE [dvbbs] SET MULTI_USER ;.W0Aa
GO "\BP+AF
7、日志清除 n/8Kb.Vf
SET NOCOUNT ON Xx|&%b{{r
DECLARE @LogicalFileName sysname, s80_e
@MaxMinutes INT, %1VMwqC]E
@NewSize INT MQY1he2M
USE tablename -- 要操作的数据库名 W'XMC"
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ,mYoxEB kl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !Y]}&pUP
@NewSize = 1 -- 你想设定的日志文件的大小(M) (4 {49b
-- Setup / initialize <\^X,,WtO
DECLARE @OriginalSize int @?Y^=0
SELECT @OriginalSize = size
OV8b~k4=
FROM sysfiles R/^JyL
WHERE name = @LogicalFileName {u.V8%8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0uU%jN$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4&ea*w
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' MmWJYF=
FROM sysfiles &OhKx
WHERE name = @LogicalFileName
o@LjSQ5!
CREATE TABLE DummyTrans qqzQKN
(DummyColumn char (8000) not null) : 6>H\
DECLARE @Counter INT, {C]M]b*F6(
@StartTime DATETIME, 4rM77Uw>
@TruncLog VARCHAR(255) I9F[b#'Pn
SELECT @StartTime = GETDATE(), DJQ]NY|
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;@d%<yMf@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) XFu@XUk!K
EXEC (@TruncLog) N0vd>b
-- Wrap the log if necessary. ;7`<.y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired g=Qga09
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) z{#F9'\&
AND (@OriginalSize * 8 /1024) > @NewSize Y[~6f,?^
BEGIN -- Outer loop. zW0AB8l
SELECT @Counter = 0 &vMH
AZd
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) INbjk;k
BEGIN -- update m]-8?B1`Y
INSERT DummyTrans VALUES ('Fill Log') Y6L+3*Qt
DELETE DummyTrans l IFt/
SELECT @Counter = @Counter + 1 km c9P&
END u=E?N:I~F
EXEC (@TruncLog) [V)sCAW
END h{* O9O<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + p fBO5Ys
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + "ZyHt HAK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' P/I{q s
FROM sysfiles ^CK)q2K>[
WHERE name = @LogicalFileName )b%c]!
DROP TABLE DummyTrans "{x~j\<
SET NOCOUNT OFF 7 $9fGo
8、说明:更改某个表 "}OFwes
exec sp_changeobjectowner 'tablename','dbo' .897Z|$VB
9、存储更改全部表 2 !;4mij,
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g
Go
@OldOwner as NVARCHAR(128), rp'fli?0e
@NewOwner as NVARCHAR(128) 4{vd6T}V!
AS Eq8OAuN
DECLARE @Name as NVARCHAR(128) ?J~JQe42
DECLARE @Owner as NVARCHAR(128)
l#~FeD
DECLARE @OwnerName as NVARCHAR(128) /5x`TT
DECLARE curObject CURSOR FOR T),:8/
select 'Name' = name, o`77gkLO
'Owner' = user_name(uid) z'qVEHc)
from sysobjects 7%E1F)%
where user_name(uid)=@OldOwner *(vq-IE\$
order by name -YuvEm#f
OPEN curObject sRZ:9de+
FETCH NEXT FROM curObject INTO @Name, @Owner YjX=@
WHILE(@@FETCH_STATUS=0) 42wcpSp
BEGIN MtYP3:
if @Owner=@OldOwner ^X&9"x)4
begin \W}EyA
set @OwnerName = @OldOwner + '.' + rtrim(@Name) lTB!yF.r|
exec sp_changeobjectowner @OwnerName, @NewOwner Pj.~|5gnf
end ,#E5 /'c`
-- select @name,@NewOwner,@OldOwner oba*w;
FETCH NEXT FROM curObject INTO @Name, @Owner okcl-q
END =wj~6:Bf
close curObject FvJSJ.;E,
deallocate curObject Wl#^Eu\g1W
GO {;4PP463
10、SQL SERVER中直接循环写入数据 q9
;\B&
declare @i int xF/D YXC{8
set @i=1 .HQ<6k:
while @i<30 4 P;O8KA5y
begin ~d8>#v=Q`
insert into test (userid) values(@i) 9/$P_Q:3
set @i=@i+1 >o} ati
end ^97ZH)Ww
小记存储过程中经常用到的本周,本月,本年函数 jkP70Is
Dateadd(wk,datediff(wk,0,getdate()),-1) KNg5Ptk
Dateadd(wk,datediff(wk,0,getdate()),6) 5qr!OEF2
Dateadd(mm,datediff(mm,0,getdate()),0) vf yva
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fv_wK_.
%:
Dateadd(yy,datediff(yy,0,getdate()),0) Q$vr`yV#=6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) YW{V4yW
上面的SQL代码只是一个时间段 ? g{,MP5
Dateadd(wk,datediff(wk,0,getdate()),-1) >Y+KL
Dateadd(wk,datediff(wk,0,getdate()),6) &JlR70gdHi
就是表示本周时间段. .zAafi0
下面的SQL的条件部分,就是查询时间段在本周范围内的: ziycyf.d
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,j nRt%W
而在存储过程中 Uu
X"AFy~\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) s4$m<"~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4sj%: