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。 {1li3K&0s
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一、基础 'e_^s+l)a
1、说明:创建数据库 L,*2tJcC<
CREATE DATABASE database-name tPIT+1. ]z
2、说明:删除数据库 xgn@1.}G
drop database dbname ~J^Gzl
3、说明:备份sql server !FX0Nx=oi
--- 创建 备份数据的 device 7pH(_-TF
USE master |&`NB|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' }]$%aMxy T
--- 开始 备份 fNPHc_?Ybj
BACKUP DATABASE pubs TO testBack kngkG|du
4、说明:创建新表 K??%Qh5l+C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lCLz!k2di
根据已有的表创建新表: v!27q*;8H
A:create table tab_new like tab_old (使用旧表创建新表) V0q./NuO
B:create table tab_new as select col1,col2... from tab_old definition only RMUR@o5N
5、说明:删除新表 YHAhF@&
drop table tabname S9S8T+
6、说明:增加一个列 .0k ltnB
Alter table tabname add column col type tsVQXvo
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 /k qW
7、说明:添加主键: Alter table tabname add primary key(col) GGo)k1T|)
说明:删除主键: Alter table tabname drop primary key(col) /)sA{q
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8、说明:创建索引:create [unique] index idxname on tabname(col....) mnZ/rb
删除索引:drop index idxname }&BE*U8_
注:索引是不可更改的,想更改必须删除重新建。 rCR?]1*Z
9、说明:创建视图:create view viewname as select statement \W=~@k
删除视图:drop view viewname ) (unL`y
10、说明:几个简单的基本的sql语句 CE]0OY
选择:select * from table1 where 范围 6My=GByC
插入:insert into table1(field1,field2) values(value1,value2) xy)Y)yp
删除:delete from table1 where 范围 u&yAMWl
更新:update table1 set field1=value1 where 范围 qgg/_H:;w
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! nd*9vxM
排序:select * from table1 order by field1,field2 [desc] 92!1I$zi
总数:select count as totalcount from table1 Wjc1 EW!2x
求和:select sum(field1) as sumvalue from table1 bRT1~)
平均:select avg(field1) as avgvalue from table1 {XH!`\
最大:select max(field1) as maxvalue from table1 @8E mY,{;
最小:select min(field1) as minvalue from table1 =Ryh@X&
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11、说明:几个高级查询运算词 4Xi
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A: UNION 运算符 (jd)sf6Tj[
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。 (7^5jo[D
B: EXCEPT 运算符 1"?3l`i
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。 Sm(X/P=z
C: INTERSECT 运算符 &6<>hqR^
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。 1)yEx1
注:使用运算词的几个查询结果行必须是一致的。 4XpW#>
12、说明:使用外连接 BOClMeA4
A、left outer join: -9TNU7^
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。 \H|tc#::{
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 'X_8j` ]#
B:right outer join: >]K:lJ]l
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。 Z^ynw8k"
C:full outer join: )d5Hv2/0
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。 Lf0Y|^!S_u
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二、提升 UJ0fYTeuI
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) %\Dvng6$
法一:select * into b from a where 1<>1 Gu[G_^>
法二:select top 0 * into b from a C#{s[l \]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) QY2/mtI
insert into b(a, b, c) select d,e,f from b; 29 {Ep
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) 0,$eiY)u$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ~2u~}v5m7
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1AMxZ (e
4、说明:子查询(表名1:a 表名2:b) K"4m)B~@Y
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) QJiU"1
5、说明:显示文章、提交人和最后回复时间 Y3@\uM`2#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Xi"+{6
6、说明:外连接查询(表名1:a 表名2:b) 0'8_:|5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '-C%?*ku
7、说明:在线视图查询(表名1:a ) zURxXo/\V
select * from (SELECT a,b,c FROM a) T where t.a > 1; c1 aCN
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 "Kky|(EQ$$
select * from table1 where time between time1 and time2 wJ#fmQXKJ5
select a,b,c, from table1 where a not between 数值1 and 数值2 WqQAt{W/<
9、说明:in 的使用方法 &j=FxF9o
select * from table1 where a [not] in ('值1','值2','值4','值6') n7-|\p!xP6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 YZ>L\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) jZwv!-:
11、说明:四表联查问题: ffyDi 1Q
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 ..... OBrbWXp@
12、说明:日程安排提前五分钟提醒 KFQ 4vavNh
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %]NaHf
13、说明:一条sql 语句搞定数据库分页 6{Y3-Pxg
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 .}IxZM[}D
14、说明:前10条记录 ^6R
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select top 10 * form table1 where 范围 @
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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.) -M=#U\D
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7|$cM7_r
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 5?6U@??]
(select a from tableA ) except (select a from tableB) except (select a from tableC) D<=x<.
17、说明:随机取出10条数据 R>Q&Ax
select top 10 * from tablename order by newid() Ja1[vO"YgP
18、说明:随机选择记录 EJC{!06L'/
select newid() bu[PQsT
19、说明:删除重复记录 2?vjj:P+h
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ^3~+| A98M
20、说明:列出数据库里所有的表名 2J7=
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select name from sysobjects where type='U' bm/pLC6%.
21、说明:列出表里的所有的 cyYsz'i m
select name from syscolumns where id=object_id('TableName') X S:W{tL!
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。 X}"Ic@8
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 D*7JE
显示结果: Y)~Y; ;/G
type vender pcs Y:o\qr!Y
电脑 A 1 >4I,9TO
电脑 A 1 3B *b d
光盘 B 2 5Bwr\]%$P
光盘 A 2 /~sNx
手机 B 3 !~sgFR8W
手机 C 3 k55s-%Ayr
23、说明:初始化表table1 ^eF%4DUC;
TRUNCATE TABLE table1 VN3"$@-POK
24、说明:选择从10到15的记录 B=<>OYH
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^:krfXT
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三、技巧 5(9SIj^O
1、1=1,1=2的使用,在SQL语句组合时用的较多 8{0=tOXx{
"where 1=1" 是表示选择全部 "where 1=2"全部不选, FYwMmb
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如: Tt;h?
if @strWhere !='' l]g
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begin \\ZR~f!<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Rgstk/1
end TRLz>m Q
else -4 *94<
begin 8x)&4o@
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' dUt$kB
end Bqcih$`BVU
我们可以直接写成 k4n4BL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere CBkI!
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2、收缩数据库 cj[a^ ZH
--重建索引 EN,PI~~F
DBCC REINDEX c >O>|*I
DBCC INDEXDEFRAG kdgU1T@y.
--收缩数据和日志 0f_+h %%=
DBCC SHRINKDB ]n \Qa
DBCC SHRINKFILE EWb'#+BP
3、压缩数据库 7lLh4__;`6
dbcc shrinkdatabase(dbname) A{Kc"s4fO
4、转移数据库给新用户以已存在用户权限 :.VI*X:aQh
exec sp_change_users_login 'update_one','newname','oldname' V
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go z`}<mY
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5、检查备份集 %>];F~z
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 0 _n
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6、修复数据库 )a7nr<)aU
ALTER DATABASE [dvbbs] SET SINGLE_USER c*m7'\
GO )7aUDsu>4
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK *\-$.w)k
GO CI#6r8u
ALTER DATABASE [dvbbs] SET MULTI_USER JJQS7,vG
GO ]NEr]sc-"F
7、日志清除 h]+UK14m
SET NOCOUNT ON *jf%Wj)0M
DECLARE @LogicalFileName sysname, 21T#NYfew
@MaxMinutes INT, gR\z#Sg
@NewSize INT VxP cC+
USE tablename -- 要操作的数据库名 t6,bA1*5y
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 8mm]>u$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =K\xE"
@NewSize = 1 -- 你想设定的日志文件的大小(M) Yy 8?X9r.
-- Setup / initialize n%S%a>IQj
DECLARE @OriginalSize int >fq]c
SELECT @OriginalSize = size sQ}E4Iq1#S
FROM sysfiles ;_K3/:
WHERE name = @LogicalFileName Xf YbWR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MwuRxeRO-
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WR.>?IG2E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >iV2>o _
FROM sysfiles +QW|8b
WHERE name = @LogicalFileName '=WPi_Z5:C
CREATE TABLE DummyTrans FUO 9jX
(DummyColumn char (8000) not null) w-j^jU><3
DECLARE @Counter INT, L-9AJk>V
@StartTime DATETIME, c%+_~iBUN
@TruncLog VARCHAR(255) o#Viz:
SELECT @StartTime = GETDATE(), u]z87#4
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' PY@BgL=/
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Dq~\U&U\$
EXEC (@TruncLog) '% if< /
-- Wrap the log if necessary. /prR;'ks
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w7%.EA{N
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1RgERj
AND (@OriginalSize * 8 /1024) > @NewSize jhJ'fI
BEGIN -- Outer loop. FX
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SELECT @Counter = 0 v;sWI"Fv!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |muZv!,E
BEGIN -- update vf@toYc[E
INSERT DummyTrans VALUES ('Fill Log') iAr]Ed"9|
DELETE DummyTrans yno X=#`
SELECT @Counter = @Counter + 1 5-RA<d#
END %HD0N&
EXEC (@TruncLog) W]oILL"d
END 8+,I(+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 47=YP0r?>T
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6QYHPz
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ujf]@L?
FROM sysfiles 8Q(A1U
WHERE name = @LogicalFileName :\]qB&
DROP TABLE DummyTrans u_=^Bd
SET NOCOUNT OFF _u9bZ'
8、说明:更改某个表 rU
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exec sp_changeobjectowner 'tablename','dbo' 3^,p$D<T:,
9、存储更改全部表 0aqq*e'c
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch YD,<]q%
@OldOwner as NVARCHAR(128), 0JXXJ:d B
@NewOwner as NVARCHAR(128)
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AS -y'tz,En.
DECLARE @Name as NVARCHAR(128) w+Y_TJ%
DECLARE @Owner as NVARCHAR(128) dAr=X4LE
DECLARE @OwnerName as NVARCHAR(128) {
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DECLARE curObject CURSOR FOR
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select 'Name' = name, s>I~%+V.?:
'Owner' = user_name(uid) W) ?s''WE;
from sysobjects F|&%Z(@a
where user_name(uid)=@OldOwner 4d8}g25C
order by name +&4@HHU{G
OPEN curObject &U_T1-UR2
FETCH NEXT FROM curObject INTO @Name, @Owner mM2DZ^"j(
WHILE(@@FETCH_STATUS=0) FM"[:&>
BEGIN 1l s 8 h
if @Owner=@OldOwner ~hb;kc3
begin 8
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) &e3pmHp'
exec sp_changeobjectowner @OwnerName, @NewOwner T`2a)
end A\})H
-- select @name,@NewOwner,@OldOwner 7?ILmYBw
FETCH NEXT FROM curObject INTO @Name, @Owner 0C4Os p
END AbL(F#{
close curObject }p>l,HD
deallocate curObject s[;1?+EI
GO "9IR|
10、SQL SERVER中直接循环写入数据 X2mZ~RB(p
declare @i int pD]2.O
set @i=1 )S9}uOG#
while @i<30 `4,]Mr1b
begin mYFc53B
insert into test (userid) values(@i) $wcTUl
set @i=@i+1 ;o?o92d
end ui80}%
小记存储过程中经常用到的本周,本月,本年函数 JYnyo$m/
Dateadd(wk,datediff(wk,0,getdate()),-1) wAo6:)
Dateadd(wk,datediff(wk,0,getdate()),6) qGi\*sc>x
Dateadd(mm,datediff(mm,0,getdate()),0) d~KTUgH'<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) GA"vJFQ
Dateadd(yy,datediff(yy,0,getdate()),0) kyf(V)APPu
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) U45-R-
上面的SQL代码只是一个时间段 } x
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Dateadd(wk,datediff(wk,0,getdate()),-1) w{riXOjS4
Dateadd(wk,datediff(wk,0,getdate()),6) p\}!uS4 (
就是表示本周时间段. lNMJcl3
下面的SQL的条件部分,就是查询时间段在本周范围内的: S`& yVzv
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %reW/;)l{
而在存储过程中 | Pqs)Mb]
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ZU`HaL$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9hgIQl