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。 ;N4b~k)
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一、基础 is%qG?,P
1、说明:创建数据库 L\8tqy.
CREATE DATABASE database-name ~\c]!%)o
2、说明:删除数据库 iO;q]
drop database dbname DT_HG|
3、说明:备份sql server (yduU
--- 创建 备份数据的 device uuzDu]Gwu
USE master \Clz#k8l1
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0sq1SHI{
--- 开始 备份 `J^J_s
BACKUP DATABASE pubs TO testBack 9KVeFl
4、说明:创建新表 =j 6amk-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AAkdwo
根据已有的表创建新表: @ba5iIt
A:create table tab_new like tab_old (使用旧表创建新表) s%Q
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B:create table tab_new as select col1,col2... from tab_old definition only ^IuHc_
5、说明:删除新表 xNTO59Y-s
drop table tabname n`T
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6、说明:增加一个列 2jf-vWV_
Alter table tabname add column col type (u-i{<
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。 nn"!x|c
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) :2?J#/o
8、说明:创建索引:create [unique] index idxname on tabname(col....) inavi5.
删除索引:drop index idxname 9)Y]05us
注:索引是不可更改的,想更改必须删除重新建。 }> k9]Y
9、说明:创建视图:create view viewname as select statement 3_2(L"S2
删除视图:drop view viewname |,j6cFNw
10、说明:几个简单的基本的sql语句 .!Kdi| a)
选择:select * from table1 where 范围 h[%`'(
插入:insert into table1(field1,field2) values(value1,value2) *usfJ-
删除:delete from table1 where 范围 P@:#NU[
更新:update table1 set field1=value1 where 范围 +I#5?
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! KP7bU9odJ
排序:select * from table1 order by field1,field2 [desc] |n3PznV
总数:select count as totalcount from table1 Re('7m h~
求和:select sum(field1) as sumvalue from table1 Xd>4n7nb$`
平均:select avg(field1) as avgvalue from table1 lNQ t
最大:select max(field1) as maxvalue from table1 n*%<!\gJ
最小:select min(field1) as minvalue from table1 34
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11、说明:几个高级查询运算词 mCe,(/>l+
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A: UNION 运算符 oYnA 3
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。 _/ZIDIn
B: EXCEPT 运算符 nbMnqkNb
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。 VcT(n7
C: INTERSECT 运算符 {j[[E/8N!y
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.X?wyg5
注:使用运算词的几个查询结果行必须是一致的。 $BG4M?Y
12、说明:使用外连接 y@'8vOh`
A、left outer join: &F[/@
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 3x9O<H}
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c V<
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B:right outer join: [a\:K2*'
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Lw?4xerLsb
C:full outer join: =L9sb!
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 8Vv"'CU#
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二、提升 H^p?t=Y
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) F'W{\4
法一:select * into b from a where 1<>1 oL#^=vid"
法二:select top 0 * into b from a ~;,]/'O
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 1b
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insert into b(a, b, c) select d,e,f from b; Z:09]r1
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) JJ q= {;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;_M .(8L
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. n[CESo%[
4、说明:子查询(表名1:a 表名2:b) p-UACMN&c
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) W+&ZYN'E
5、说明:显示文章、提交人和最后回复时间 ]x?9lQ1&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b D|,d_W
6、说明:外连接查询(表名1:a 表名2:b) |:`f#H
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c BKIAc6
7、说明:在线视图查询(表名1:a ) x
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select * from (SELECT a,b,c FROM a) T where t.a > 1; eP|:b &
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 FD*`$.e3\
select * from table1 where time between time1 and time2 ouK&H|'
select a,b,c, from table1 where a not between 数值1 and 数值2 bT*MJ7VVm
9、说明:in 的使用方法 S&8gZ~B
select * from table1 where a [not] in ('值1','值2','值4','值6') ]<A|GY0q1
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Z,qo
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [ECSJc&i
11、说明:四表联查问题: U2=5Nt5
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 ..... wt[MzpR P
12、说明:日程安排提前五分钟提醒 %F9%t
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 g}@_
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13、说明:一条sql 语句搞定数据库分页 |!i3Y=X
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 RO=[Rr!
14、说明:前10条记录 AQU4~g
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select top 10 * form table1 where 范围 /d9I2~}B
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.) kWc%u-_
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .B{3=z^
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 QQ!%lbMK]
(select a from tableA ) except (select a from tableB) except (select a from tableC) hAHl+q)w?
17、说明:随机取出10条数据 bKYLBu:
select top 10 * from tablename order by newid() uI@:\Rss
18、说明:随机选择记录 FEw51a+V
select newid() _+N*4
19、说明:删除重复记录 Ku*@4#<L6h
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !]&a/$U
20、说明:列出数据库里所有的表名 OljUK,I]
select name from sysobjects where type='U' 69ia #
21、说明:列出表里的所有的 U_m<W$"HF
select name from syscolumns where id=object_id('TableName') 4Z"DF)+}
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。 !m^;Apuy
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\1h=V)!H
显示结果: 7gfNe kr~W
type vender pcs :h=];^/E
电脑 A 1 2)h
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电脑 A 1 v$s3f|Y
光盘 B 2 F:x" RbbF
光盘 A 2 rXuhd [!(P
手机 B 3 )\l}i%L:
手机 C 3 $SRpFz5y$
23、说明:初始化表table1 Yvs)H'n=
TRUNCATE TABLE table1 *oL?R2#7
24、说明:选择从10到15的记录 vXLiYWo
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 63QMv[`,
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三、技巧 ,>V|%tD'
1、1=1,1=2的使用,在SQL语句组合时用的较多 ++-HdSHY
"where 1=1" 是表示选择全部 "where 1=2"全部不选, nZ>qM]">u
如: /+.Bc(`
if @strWhere !='' ]Vo;ZY_\
begin 4 FW~Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %N7b
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end v*<hE>J0
else jxL}tS{j
begin |sMRIW,P
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' SGre[+m~m
end U8-#W(tRR
我们可以直接写成 /jaTH_Q),:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )~v`dwKj;
2、收缩数据库 ;"-(QE?Mv
--重建索引 K>l$Y#x}k
DBCC REINDEX F?\XhoJ3G
DBCC INDEXDEFRAG 4Pe%*WTX
--收缩数据和日志 x5YW6R.<t
DBCC SHRINKDB $[T^S
DBCC SHRINKFILE ' 7+x,TszI
3、压缩数据库 t*m04* }
dbcc shrinkdatabase(dbname) %/"I.\%d
4、转移数据库给新用户以已存在用户权限 2Hw&}8
exec sp_change_users_login 'update_one','newname','oldname' vP`Sz}FU
go a$yAF4HR<
5、检查备份集 aTuD|s
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9u ^PM
6、修复数据库 ~m8".Z"
ALTER DATABASE [dvbbs] SET SINGLE_USER 0f&B;?)!
GO .LhIB?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK u)Y~+ [Q
GO O`Er*-O
ALTER DATABASE [dvbbs] SET MULTI_USER :f
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GO LQ`s> q
7、日志清除 #( F/P!qk
SET NOCOUNT ON JS<S?j?*/
DECLARE @LogicalFileName sysname, <qT[
@MaxMinutes INT, ?1*Ka
@NewSize INT 0_q8t!<xJw
USE tablename -- 要操作的数据库名 y^zII5|s
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 U>w#`Sy[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;{EIx*<d
@NewSize = 1 -- 你想设定的日志文件的大小(M) }(A`aB_
-- Setup / initialize yG)xsY V
DECLARE @OriginalSize int n^B9Mh@
SELECT @OriginalSize = size >h1 3i@`r
FROM sysfiles 1K?RA*aj
WHERE name = @LogicalFileName ;>np2K<`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %V71W3>6WS
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !TvNT}4 Z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' H )hO/1m
FROM sysfiles _8A
WHERE name = @LogicalFileName z`$jxSLm
CREATE TABLE DummyTrans (-Cxv`7
(DummyColumn char (8000) not null) nNz1gV:0X
DECLARE @Counter INT, ]6L;
@StartTime DATETIME, {L~j;p_G&
@TruncLog VARCHAR(255) +wc8rE6+W
SELECT @StartTime = GETDATE(), 0gO_dyB
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Swz{5 J2C
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0b6jGa
EXEC (@TruncLog) |a4cER.'2^
-- Wrap the log if necessary. a?jUm.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |0ATH`{
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 6D|[3rXr
AND (@OriginalSize * 8 /1024) > @NewSize pMB!I9q
BEGIN -- Outer loop. 9uR+
SELECT @Counter = 0 hb#Nm6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) LvtHWt
BEGIN -- update vF@hg)A
INSERT DummyTrans VALUES ('Fill Log') Wip@MGtJ
DELETE DummyTrans (VDY]Q)
SELECT @Counter = @Counter + 1 SW5V:|/
END uonCD8
EXEC (@TruncLog) #(swVo:+E
END T<yAfnTb`
SELECT 'Final Size of ' + db_name() + ' LOG is ' + X-LCIT|1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /By:S/[1pL
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 'yxN1JF
FROM sysfiles O+x"c3@Z)D
WHERE name = @LogicalFileName $`j%z@[g
DROP TABLE DummyTrans WX
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SET NOCOUNT OFF Zc 9@G-
8、说明:更改某个表 oC
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exec sp_changeobjectowner 'tablename','dbo' } I>6 8dS[
9、存储更改全部表 !C\$=\$
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 9d&@;&al
@OldOwner as NVARCHAR(128), -p.c8B
@NewOwner as NVARCHAR(128) ypU-/}Cf,
AS Y`F) UwKK
DECLARE @Name as NVARCHAR(128) $B%wK`J
DECLARE @Owner as NVARCHAR(128) }Q$}LR@
DECLARE @OwnerName as NVARCHAR(128) (xpt_]Q!H
DECLARE curObject CURSOR FOR J^<Gi/:*^
select 'Name' = name, fF6bEJl3
'Owner' = user_name(uid) /]j^a:#"6t
from sysobjects ~,ZU+
where user_name(uid)=@OldOwner :I_p4S.)
order by name r$[`A_
OPEN curObject e}dGK=`
FETCH NEXT FROM curObject INTO @Name, @Owner r1<dZtb
WHILE(@@FETCH_STATUS=0) i>z_6Gax*[
BEGIN m)AF9#aT2
if @Owner=@OldOwner F>Pr`T?>
begin OfG/7pw5%B
set @OwnerName = @OldOwner + '.' + rtrim(@Name) lXtsnQOOK
exec sp_changeobjectowner @OwnerName, @NewOwner riR(CJ}Ff
end LMKhtOZ?
-- select @name,@NewOwner,@OldOwner 5aj%<r
FETCH NEXT FROM curObject INTO @Name, @Owner I3gl+)Q
END hL4T7`
close curObject Hg&.U;n
deallocate curObject U!d|5W.{Q
GO
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10、SQL SERVER中直接循环写入数据 n%|og^\0
declare @i int >{6U1ft):
set @i=1 nuKcq!L
while @i<30 "@z X{^:
begin Emy=q5ryl
insert into test (userid) values(@i) r>: ~!o*
set @i=@i+1 Su/8P[q_
end {W+IUvn
小记存储过程中经常用到的本周,本月,本年函数 vf&_
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Dateadd(wk,datediff(wk,0,getdate()),-1) KH$|wv
Dateadd(wk,datediff(wk,0,getdate()),6) s&hJ[$i
Dateadd(mm,datediff(mm,0,getdate()),0) E1r-$gf_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) k5M5bH',
Dateadd(yy,datediff(yy,0,getdate()),0) dx@|M{jz'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Mj&G5R~_
上面的SQL代码只是一个时间段 s$% t2UaV
Dateadd(wk,datediff(wk,0,getdate()),-1) Hr_5N,
Dateadd(wk,datediff(wk,0,getdate()),6) `j1oxJm
就是表示本周时间段. azz=,^U#
下面的SQL的条件部分,就是查询时间段在本周范围内的: |\zzOfaO
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) *\.8*6*$!
而在存储过程中 rJZR8bo
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) lArKfs/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) +7\d78U