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。 ^W}(]jL
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一、基础 ZmM/YPy
1、说明:创建数据库 ~m4{GzB
CREATE DATABASE database-name 5k /Y7+*?E
2、说明:删除数据库 =Yd{PZ*fR
drop database dbname RE*;_DF
3、说明:备份sql server l]:nncpns
--- 创建 备份数据的 device ,LD[R1TU8
USE master 7-p9IFcA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 3RSiu}
--- 开始 备份 =}SH*xi6
BACKUP DATABASE pubs TO testBack 0M[O(.x
4、说明:创建新表 {[Bo"a>%
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h%2;B;p]
根据已有的表创建新表: kH&KE5
A:create table tab_new like tab_old (使用旧表创建新表) e15_$M;RW
B:create table tab_new as select col1,col2... from tab_old definition only iA=QK
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5、说明:删除新表 /HlLfW
drop table tabname 2@&|/O6_\h
6、说明:增加一个列 q#}#A@Rg
Alter table tabname add column col type (+M]C]
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。 d#Hl3]wT
7、说明:添加主键: Alter table tabname add primary key(col) H83Gx;
说明:删除主键: Alter table tabname drop primary key(col) \U(;%V
8、说明:创建索引:create [unique] index idxname on tabname(col....) 2.xA' \M
删除索引:drop index idxname 6p;G~,bd~
注:索引是不可更改的,想更改必须删除重新建。 CJn{tP
9、说明:创建视图:create view viewname as select statement ^T^l3B[
删除视图:drop view viewname `>.^/SGu>?
10、说明:几个简单的基本的sql语句 "4`i]vy8
选择:select * from table1 where 范围 "'#18&N
插入:insert into table1(field1,field2) values(value1,value2) g>L4N.ZH_v
删除:delete from table1 where 范围 R&lJ& SgC
更新:update table1 set field1=value1 where 范围 LIm{Y`XU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! H>zX8qP+
排序:select * from table1 order by field1,field2 [desc] . 5cL+G1k#
总数:select count as totalcount from table1 U%<E9G594
求和:select sum(field1) as sumvalue from table1 REEs}88);'
平均:select avg(field1) as avgvalue from table1 &?(<6v7
最大:select max(field1) as maxvalue from table1 q:}Q5gzZ
最小:select min(field1) as minvalue from table1 3I}(as{Rp
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11、说明:几个高级查询运算词 [9hslk
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A: UNION 运算符 fN!ci']
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。 &3@{?K
B: EXCEPT 运算符 ||xiKg
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。 <l#|I'hP
C: INTERSECT 运算符 -VC
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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。 *VP-fyJp
注:使用运算词的几个查询结果行必须是一致的。 :!'!V>#g
12、说明:使用外连接 BXzn-S
A、left outer join: y}\d]*5
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。 Q+i
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 7I#<w[l>k
B:right outer join: d ynq)lf
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。 ryC7O'j_P
C:full outer join: Ba8 s
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。 5 R*
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二、提升 XCo3pB
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) d~|/LR5
法一:select * into b from a where 1<>1 ;Xr|['\'
法二:select top 0 * into b from a PLV-De
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Ic<J]+Xq
insert into b(a, b, c) select d,e,f from b; ?D\6@G:,#@
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) "p"M9P'
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 X2PyFe
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~MpcVI_K
4、说明:子查询(表名1:a 表名2:b) c}-WK*v
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) aAi"
5、说明:显示文章、提交人和最后回复时间 qQ{i2D%)?f
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b *7JsmN?
6、说明:外连接查询(表名1:a 表名2:b) *"HA=-Z;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c n N_Ylw
7、说明:在线视图查询(表名1:a ) N!Q~?/!d
select * from (SELECT a,b,c FROM a) T where t.a > 1; QnZ7e#@UP
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 &tjv.t
select * from table1 where time between time1 and time2 \*
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select a,b,c, from table1 where a not between 数值1 and 数值2 Cqra\
9、说明:in 的使用方法 9 aacW
select * from table1 where a [not] in ('值1','值2','值4','值6') {L#+v~d^'n
10、说明:两张关联表,删除主表中已经在副表中没有的信息 [
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) w vnuE<o8
11、说明:四表联查问题: 3
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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 ..... LP{@r ic
12、说明:日程安排提前五分钟提醒 l`b%imX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *?`<Ea
13、说明:一条sql 语句搞定数据库分页 O={
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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 ,UA-Pq3}
14、说明:前10条记录 U 6`E\?d`
select top 10 * form table1 where 范围 'VQ
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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.) 713)D4y}
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _yu_Ev}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 V.?Oly
(select a from tableA ) except (select a from tableB) except (select a from tableC) %gbvX^E?
17、说明:随机取出10条数据 Cu,#w3JR
select top 10 * from tablename order by newid() 2+'4 m#@)
18、说明:随机选择记录 >$/PfyY7@#
select newid() |WUm;o4E`U
19、说明:删除重复记录 9`|
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) g+zfa.wQ
20、说明:列出数据库里所有的表名 AfaoFn+
select name from sysobjects where type='U' %AV[vr,
21、说明:列出表里的所有的 ;#+Se,)
select name from syscolumns where id=object_id('TableName') {[tx^b
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。 iqAME%m
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 AZ'"Ua
显示结果: UPr8Q^wm
type vender pcs g>&b&X&Y_
电脑 A 1 J.g4I|{
电脑 A 1 ,>vI|p,/G*
光盘 B 2 :h!&.FB
光盘 A 2 Dxx`<=&g
手机 B 3 JZom#A.
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手机 C 3 eI:;l];G9
23、说明:初始化表table1 5a^b{=#Y
TRUNCATE TABLE table1 --'!5)U
24、说明:选择从10到15的记录 bKb}VP
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ;z3w#fNMv
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三、技巧 #
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1、1=1,1=2的使用,在SQL语句组合时用的较多 C0#"U f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, X ^\kI1
如: cfrvx^,2&
if @strWhere !='' "i1r9TLc
begin NkYU3[m$v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >}|Vmy[/
end ,K 1X/),
else 'H|=]n0
begin !3JYG
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?T\_"G
end xZ.c@u6:
我们可以直接写成 t^KoqJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere G&f~A;'7k
2、收缩数据库 go[(N6hN
--重建索引 X{-[
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DBCC REINDEX Vv<Tjr
DBCC INDEXDEFRAG hnp-x3
--收缩数据和日志 =0gfGwD{
DBCC SHRINKDB D@
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DBCC SHRINKFILE 7$/%c{o
3、压缩数据库 idLCq^jnJ
dbcc shrinkdatabase(dbname) *5Aq\g,n
4、转移数据库给新用户以已存在用户权限 ~K-_]*[x
exec sp_change_users_login 'update_one','newname','oldname' 4Px
go Q?7:XbN
5、检查备份集 +~] :oj
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' GT(nW|v
6、修复数据库 jn/
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ALTER DATABASE [dvbbs] SET SINGLE_USER f6O5k8n
GO VsTa!V^~
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,^d!K(xb
GO yG%<LP2p@f
ALTER DATABASE [dvbbs] SET MULTI_USER W%.ou\GN^t
GO %@4/W N
7、日志清除 ;~
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SET NOCOUNT ON >~)IsQ*%
DECLARE @LogicalFileName sysname, \8HLQly|@
@MaxMinutes INT, 'V-_3WWxU
@NewSize INT 7Ew.6!s#n1
USE tablename -- 要操作的数据库名 r1o_i;rg
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 I,0Z* rw
@MaxMinutes = 10, -- Limit on time allowed to wrap log. = m6yH_`@
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1p]Z9$Y
-- Setup / initialize IP
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DECLARE @OriginalSize int wg0hm#X
SELECT @OriginalSize = size WymBjDos:
FROM sysfiles wO&2S-;_K
WHERE name = @LogicalFileName !v`C-1}70
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Zv8I`/4?
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + TP-<Lhy
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' H.R7,'9
FROM sysfiles 2B<0|EGtzw
WHERE name = @LogicalFileName jh3XG
CREATE TABLE DummyTrans SK&? s`
(DummyColumn char (8000) not null) YLO/J2['
DECLARE @Counter INT, JRT,%;*,
@StartTime DATETIME, irRe}
@TruncLog VARCHAR(255) e9e7_QG_-
SELECT @StartTime = GETDATE(), $GcVI;a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v*UJ4r
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LsGu-Y5^
EXEC (@TruncLog) _8;)J
-- Wrap the log if necessary. 1E'/! |
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >QJfTkD$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 3Q-[)Z )
AND (@OriginalSize * 8 /1024) > @NewSize gJv;{;%
BEGIN -- Outer loop. |DZ3=eWZ
SELECT @Counter = 0 w6w'Jx
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cHO8%xu`
BEGIN -- update ! !9l@
INSERT DummyTrans VALUES ('Fill Log') V`;$Ua;y
DELETE DummyTrans {?zbrgQ<Z
SELECT @Counter = @Counter + 1 7=gv4arRwt
END rt5eN:'qY
EXEC (@TruncLog) P
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END RXDPT
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5f'<0D;K
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + C1YG=!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xU5+"t~
FROM sysfiles PiTe/
WHERE name = @LogicalFileName _o-lNt+
DROP TABLE DummyTrans c'8a)j$$+
SET NOCOUNT OFF 1FO T
8、说明:更改某个表 <y30t[.E6
exec sp_changeobjectowner 'tablename','dbo' XA%a7Xtni
9、存储更改全部表 iH#b"h{w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch z%pD3J?>
@OldOwner as NVARCHAR(128), 9^5D28y
@NewOwner as NVARCHAR(128) aTx*6;-PH
AS `AO<r
DECLARE @Name as NVARCHAR(128) /j0zb&
DECLARE @Owner as NVARCHAR(128) zJJ6"9sl
DECLARE @OwnerName as NVARCHAR(128) :y!%GJW
DECLARE curObject CURSOR FOR ]|y]?7
select 'Name' = name, tgX},OU^
'Owner' = user_name(uid) H^e0fm
from sysobjects kQY+D1
where user_name(uid)=@OldOwner 6uAo0+-k
order by name 4\6-sL?rW
OPEN curObject W6>SYa
FETCH NEXT FROM curObject INTO @Name, @Owner .;'3Roi
WHILE(@@FETCH_STATUS=0) ;C+g)BW
BEGIN nHB=*Mj DV
if @Owner=@OldOwner ;N FTdP
begin =b* Is,R/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) \f AL:mJ
exec sp_changeobjectowner @OwnerName, @NewOwner U=G^wL
end ps*dO
-- select @name,@NewOwner,@OldOwner Qf}^x9'
FETCH NEXT FROM curObject INTO @Name, @Owner j+>#.22+
END sMikTwR/^
close curObject O73 /2=1V
deallocate curObject c T!L+zg
GO S24wv2Uw i
10、SQL SERVER中直接循环写入数据 ZPISclSA+
declare @i int \\WIu?
set @i=1 i{$h]D_fD
while @i<30 ,z1fiq
begin >,JA=s
insert into test (userid) values(@i) kZ0|wML8
set @i=@i+1 -a}d
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end UW%.G
小记存储过程中经常用到的本周,本月,本年函数 HcrI3v|6
Dateadd(wk,datediff(wk,0,getdate()),-1) 8] BOq:
Dateadd(wk,datediff(wk,0,getdate()),6) 1;4]
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Dateadd(mm,datediff(mm,0,getdate()),0) #''q :^EQ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) rU{E}
Dateadd(yy,datediff(yy,0,getdate()),0) VTQxg5P c
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) y@L-qO+{&
上面的SQL代码只是一个时间段 TyCMZsvM,
Dateadd(wk,datediff(wk,0,getdate()),-1) d/57;6I_
Dateadd(wk,datediff(wk,0,getdate()),6) tv+H4/
就是表示本周时间段. N~%F/`Z<+
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~alC5|wCUQ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) g`skmHS89
而在存储过程中 r9a?Y!(
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) t1I` n(]n
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) +6xEz67A<