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(Y3yyY
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一、基础 2OC dG
1、说明:创建数据库 n\>.T[$"
CREATE DATABASE database-name .^H1\p];Lw
2、说明:删除数据库 yJ J8"s~i
drop database dbname .@K#U52
3、说明:备份sql server o*_g$
--- 创建 备份数据的 device UK:M:9
USE master 9::YR;NY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' J/7u7_
--- 开始 备份
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BACKUP DATABASE pubs TO testBack `~E<Sf<M
4、说明:创建新表 W-XN4:,qI
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )"~=7)~<^
根据已有的表创建新表: M6x;BjrV
A:create table tab_new like tab_old (使用旧表创建新表) G5+]DogS
B:create table tab_new as select col1,col2... from tab_old definition only 4Q&mC"
5、说明:删除新表 W_D%|Ub2X
drop table tabname C~_q^fXJt
6、说明:增加一个列 hvcR.f)C>
Alter table tabname add column col type Cha?7F[xL
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<?X3&J
7、说明:添加主键: Alter table tabname add primary key(col) 6#-Z@fz%
说明:删除主键: Alter table tabname drop primary key(col) 1eF@_Y^a!
8、说明:创建索引:create [unique] index idxname on tabname(col....) ,whM22Af~{
删除索引:drop index idxname qAvvXs=5
注:索引是不可更改的,想更改必须删除重新建。 u2om5e:
9、说明:创建视图:create view viewname as select statement ]E..43
删除视图:drop view viewname l~{T#Q
10、说明:几个简单的基本的sql语句 qL~Pjr>cF
选择:select * from table1 where 范围 /0!$p[cjm
插入:insert into table1(field1,field2) values(value1,value2) FJlsWh4,6=
删除:delete from table1 where 范围 Xr)g
更新:update table1 set field1=value1 where 范围 W7]mfy^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i59k"pNm
排序:select * from table1 order by field1,field2 [desc] '%$-]~
总数:select count as totalcount from table1 %9.bu|`KK
求和:select sum(field1) as sumvalue from table1 h%|9]5(=
平均:select avg(field1) as avgvalue from table1 4Xr"d@2(
最大:select max(field1) as maxvalue from table1 l58l
最小:select min(field1) as minvalue from table1 nu(eLUU
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11、说明:几个高级查询运算词 m9cj7
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A: UNION 运算符 :.C)7( 8S
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。 N~0$x,bR
B: EXCEPT 运算符 GZ.?MnG
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。 $q.p$JQ:
C: INTERSECT 运算符 Q.uR<C6)v
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。 #Z#_!o
注:使用运算词的几个查询结果行必须是一致的。 ?({Pc F/
12、说明:使用外连接 B1HQz@^
A、left outer join: '>4+WZ1w5
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。 ^$6bs64FSm
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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B:right outer join: #d$d&W~gE
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。 F^[M
C:full outer join: ^>t-v
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。 YU*46 hA1B
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二、提升 _{3k+DQ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =+k&&vOAn
法一:select * into b from a where 1<>1 #{?m
法二:select top 0 * into b from a ^JiaR)#r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ByC1I.B`
insert into b(a, b, c) select d,e,f from b; hE9'F(87a
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) b^@`uDb6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 cRjL3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !~Ax
4、说明:子查询(表名1:a 表名2:b) |UABar b
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) av7q>NEZ!1
5、说明:显示文章、提交人和最后回复时间 ~4}*Dhsh
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b B/:>{2cm
6、说明:外连接查询(表名1:a 表名2:b) ~7KynE
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )sMAhk|
7、说明:在线视图查询(表名1:a ) AW]("pt
select * from (SELECT a,b,c FROM a) T where t.a > 1; IZzhJK M1V
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 wV]sGHu F}
select * from table1 where time between time1 and time2 Y^T-A}?`
select a,b,c, from table1 where a not between 数值1 and 数值2 k?z
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9、说明:in 的使用方法 X*43!\
select * from table1 where a [not] in ('值1','值2','值4','值6') /QM0.{Ypl
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8Q#t\$RY
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !tm|A`<g#<
11、说明:四表联查问题: ZY~zpC_
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 ..... _D!M
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12、说明:日程安排提前五分钟提醒 (mu{~@Hw
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 2M!+gk=+
13、说明:一条sql 语句搞定数据库分页 1nw$B[
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 iW1$!l>v
14、说明:前10条记录 uQXs>JuD
select top 10 * form table1 where 范围 \5j22L9S
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.) e_;%F`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) '|h./.K
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 #mi0x06
(select a from tableA ) except (select a from tableB) except (select a from tableC) QYFN:XZ
17、说明:随机取出10条数据 *8pe<:A#p
select top 10 * from tablename order by newid() =k[(rvU3
18、说明:随机选择记录 v3iDh8.__
select newid() (UbR%A|v;
19、说明:删除重复记录 Q-H=wJ4R
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ./aZV
20、说明:列出数据库里所有的表名 )&g2D@+{
select name from sysobjects where type='U' 9`hpa-m@
21、说明:列出表里的所有的 \1eKY^)2
select name from syscolumns where id=object_id('TableName') 5)/4)0
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。 c"oQ/x
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 ]l9,t5Y
显示结果: s\F EA"w/
type vender pcs z+5u/t
电脑 A 1 bw<~R2[
电脑 A 1 GN}9$:
光盘 B 2 6x`\
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光盘 A 2 N6-2*ES
手机 B 3 Ae,2Xi
手机 C 3 ?];~N5<'
23、说明:初始化表table1 ORFr7a'K
TRUNCATE TABLE table1 i2\\!s
24、说明:选择从10到15的记录 &km d<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc +dPE!:
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三、技巧 RBHqLg(
1、1=1,1=2的使用,在SQL语句组合时用的较多 YGZAtSf3z
"where 1=1" 是表示选择全部 "where 1=2"全部不选, XACEt~y
如: s%0[DO3NV
if @strWhere !='' z[<pi:
begin : .UX[!^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere k;AV;KWI'
end U)T/.L{0i
else JXRmu~W~l
begin :IOn`mRYu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' x1 R!
end :&\E\9
我们可以直接写成 tCF0Ah
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ! X#3w-K
2、收缩数据库 0t/z"
--重建索引 %te'J G<
DBCC REINDEX 2t
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DBCC INDEXDEFRAG cZ7F1H~
--收缩数据和日志 b5iJm-
DBCC SHRINKDB SOi(5]
DBCC SHRINKFILE NjCLL`?f
3、压缩数据库 FSXKH {Z
dbcc shrinkdatabase(dbname) &p(*i@Ms
4、转移数据库给新用户以已存在用户权限 qH}62DP3
exec sp_change_users_login 'update_one','newname','oldname' R`<{W(J;r
go $`+~QR!h
5、检查备份集 F".IB^}$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' joSr,'x
6、修复数据库 1)c=15^
ALTER DATABASE [dvbbs] SET SINGLE_USER Vq;{+j(
GO JUUF^/J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Qnu&GBM
GO c] :J/'vc
ALTER DATABASE [dvbbs] SET MULTI_USER c^q O@%s
GO p-i]l.mT5
7、日志清除 LI5cUCl
SET NOCOUNT ON d}6AHS[
DECLARE @LogicalFileName sysname, rym\5
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@MaxMinutes INT, L_CEY
@NewSize INT 3YZ3fhpw
USE tablename -- 要操作的数据库名 /:c,v-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @'G ( k;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (B?xq1Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) &VBD2_T
-- Setup / initialize `HZHVV$~
DECLARE @OriginalSize int hdNZ":1s
SELECT @OriginalSize = size bI6V &Dd
FROM sysfiles \T#(rt\j
WHERE name = @LogicalFileName C#u)$Ds
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p~{%f#V
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' B?zS_Ue
FROM sysfiles kgI.kT(=
WHERE name = @LogicalFileName 1(\I9L&J
CREATE TABLE DummyTrans MCO$>QL
(DummyColumn char (8000) not null) :_b
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DECLARE @Counter INT, 'E6gEJ
@StartTime DATETIME, Am}PXj6
@TruncLog VARCHAR(255) H2tpP~!G
SELECT @StartTime = GETDATE(), oXZ@*
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &rtz&}ZB;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) A`ertSlbhe
EXEC (@TruncLog) N*4IxY'vX/
-- Wrap the log if necessary. uq1(yyWp(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired G^eFS;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) J&0wl]w|O%
AND (@OriginalSize * 8 /1024) > @NewSize Ga/\kO)x_
BEGIN -- Outer loop. g he=mQ-
SELECT @Counter = 0 ,-NLUS
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) YH'.Yj2
BEGIN -- update :!*;0~#
INSERT DummyTrans VALUES ('Fill Log') E9+O\"e9
DELETE DummyTrans ~.y4
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SELECT @Counter = @Counter + 1 Ph!NYi,
END CIs1*:Q9
EXEC (@TruncLog) t2%bHIG}
END 68G] a N3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3@WI*PMc
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + LW8{a&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "u$]q1S
FROM sysfiles +sq,!6#G
WHERE name = @LogicalFileName >C d&K9H
DROP TABLE DummyTrans ]Pl6:FB8%@
SET NOCOUNT OFF Fl|&eO,e
8、说明:更改某个表 ?+JxQlVDt-
exec sp_changeobjectowner 'tablename','dbo' EO!cv,[a
9、存储更改全部表 9g,L1 W*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch -,CndRKx
@OldOwner as NVARCHAR(128), {]^%?]e
@NewOwner as NVARCHAR(128) sT T455h)
AS {xb%P!o`
DECLARE @Name as NVARCHAR(128) [A OluS
DECLARE @Owner as NVARCHAR(128) M#jee E-}%
DECLARE @OwnerName as NVARCHAR(128) q8yJW-GA
DECLARE curObject CURSOR FOR kQiW 5
select 'Name' = name, ^=M(K ''
'Owner' = user_name(uid) \(7# N<-
from sysobjects g&(~MD2{
where user_name(uid)=@OldOwner ]KPg=@Q/
order by name KVe'2Q<
OPEN curObject cLk+( dn
FETCH NEXT FROM curObject INTO @Name, @Owner 5^qp&
WHILE(@@FETCH_STATUS=0) ^
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BEGIN \\pyu]z
if @Owner=@OldOwner (Y@|h%1W
begin f(ec/0W
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ENF@6]
exec sp_changeobjectowner @OwnerName, @NewOwner 'C4Ll2
end N`GwL
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-- select @name,@NewOwner,@OldOwner $">NW&
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FETCH NEXT FROM curObject INTO @Name, @Owner {qdhp_~^l
END ?fX8WRdh
close curObject rVW'KN
deallocate curObject |4*2xDcl
GO v7I*W/
10、SQL SERVER中直接循环写入数据 -2u+m
declare @i int ,rPyXS9Sa{
set @i=1 OL+40 J
while @i<30 >qGR^yvb
begin cO?"
insert into test (userid) values(@i) \$Qm2XKrK
set @i=@i+1 g.VIe
end #)eJz1~
小记存储过程中经常用到的本周,本月,本年函数 T#;*I#A:
Dateadd(wk,datediff(wk,0,getdate()),-1) (ZR"O8
Dateadd(wk,datediff(wk,0,getdate()),6) SPm5tU
Dateadd(mm,datediff(mm,0,getdate()),0) s~ZC!- [;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) aV%rq9Tp
Dateadd(yy,datediff(yy,0,getdate()),0) bM_(`]&*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Uwil*Jh
上面的SQL代码只是一个时间段 o5A_j?t
Dateadd(wk,datediff(wk,0,getdate()),-1) ![C$H5
Dateadd(wk,datediff(wk,0,getdate()),6) y:Ab5/bHy
就是表示本周时间段. C3h!?5
下面的SQL的条件部分,就是查询时间段在本周范围内的: t#{>y1[29
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !d@`r1t
而在存储过程中 )/^$JYz
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) H%gD[!^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) P9chRy