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。 3v!~ cC~cI
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一、基础 ,A5) <}
1、说明:创建数据库 %:qoV0DR
CREATE DATABASE database-name |k{-l!HI
2、说明:删除数据库 U~2`P
drop database dbname oT|m1aGE
3、说明:备份sql server Yp4c'Zk
--- 创建 备份数据的 device *V;3~x!
USE master b r,+45:
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 7e&\{*
--- 开始 备份 m$$?icA
BACKUP DATABASE pubs TO testBack /LQ:Sv7
4、说明:创建新表 y/@iT8$rp
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !=*.$4
根据已有的表创建新表: ~-F?Mc
A:create table tab_new like tab_old (使用旧表创建新表) 6bZ[Kt
B:create table tab_new as select col1,col2... from tab_old definition only 7=*VpX1
5、说明:删除新表 |H ;+1
drop table tabname IGAzE(
6、说明:增加一个列 zSjgx_#U
Alter table tabname add column col type - &[z\"T
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ;</Twm;:
7、说明:添加主键: Alter table tabname add primary key(col) (w2=
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说明:删除主键: Alter table tabname drop primary key(col) BZF,=v
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?4)v`*
删除索引:drop index idxname hQgN9S5P
注:索引是不可更改的,想更改必须删除重新建。 S9Yt 1qb
9、说明:创建视图:create view viewname as select statement 3#<*k>1G?
删除视图:drop view viewname /axTh
10、说明:几个简单的基本的sql语句 0D)`2W
选择:select * from table1 where 范围 Z]-WFU_
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插入:insert into table1(field1,field2) values(value1,value2) s!6=|SS7
删除:delete from table1 where 范围 p#_[
更新:update table1 set field1=value1 where 范围 xT F=Y_
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 04y!\
排序:select * from table1 order by field1,field2 [desc] CM~MoV[k7e
总数:select count as totalcount from table1 G"S5ki`o
求和:select sum(field1) as sumvalue from table1 Kv+Bfh
平均:select avg(field1) as avgvalue from table1 e4qj .b
最大:select max(field1) as maxvalue from table1 hE!7RM+Y
最小:select min(field1) as minvalue from table1 ]X" / yAn
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11、说明:几个高级查询运算词 `%E9xcD%
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A: UNION 运算符 ZcZ;$*
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。 j.QHkI1.
B: EXCEPT 运算符 z*.v_Mx
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。 "jZm0U$,*
C: INTERSECT 运算符 e!o(g&wBj
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。 cj(X2L
注:使用运算词的几个查询结果行必须是一致的。 hswTn`f
12、说明:使用外连接 f:%SW
A、left outer join: mpef]9
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。 T#iU+)-\%
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: } 21j
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。 "oE* 9J?e
C:full outer join: K~>jApZ%
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。 "r-l8r,
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二、提升 A'DVJ9%xB
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) u3wL<$2[8
法一:select * into b from a where 1<>1 X7e/:._SAH
法二:select top 0 * into b from a sA_X<>vAKJ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
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insert into b(a, b, c) select d,e,f from b; +?e}<#vd'?
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) &LU'.jY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 jpO38H0)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. XZ:1!;
4、说明:子查询(表名1:a 表名2:b) 9oq)X[
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) DM2Q1Dh3
5、说明:显示文章、提交人和最后回复时间 4Vx+[8W
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9U10d&M(
6、说明:外连接查询(表名1:a 表名2:b) )Z:m)k>r;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~.Q4c*_b
7、说明:在线视图查询(表名1:a ) h3h8lt_|
select * from (SELECT a,b,c FROM a) T where t.a > 1; P{lh)m>
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 j<$R4A1
select * from table1 where time between time1 and time2 f8!l7{2%q
select a,b,c, from table1 where a not between 数值1 and 数值2 sfC@*Y2XT
9、说明:in 的使用方法 ]hUKuef
select * from table1 where a [not] in ('值1','值2','值4','值6') \UtS>4w\
10、说明:两张关联表,删除主表中已经在副表中没有的信息 l%bq2,-%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) fNEz
11、说明:四表联查问题: |E|T%i^}./
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 ..... qP`?M\!O
12、说明:日程安排提前五分钟提醒 XaGz].Sv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ype"7p\
13、说明:一条sql 语句搞定数据库分页 Y:%"K
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 Q2$/e+
14、说明:前10条记录 s=\7)n=,M
select top 10 * form table1 where 范围 em/Xu
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.) 2B'^`>+8S
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) R`7n^,
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'lIWuL)
(select a from tableA ) except (select a from tableB) except (select a from tableC) B'/Icg.T
17、说明:随机取出10条数据 X)NWX9^;'
select top 10 * from tablename order by newid() t>@yv#
18、说明:随机选择记录 D'?]yyrf
select newid() \I
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19、说明:删除重复记录 Wy,"cT
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w#d} TY
20、说明:列出数据库里所有的表名 0hZxN2r
select name from sysobjects where type='U' >%i9 oI<)
21、说明:列出表里的所有的 Dtt\~m;AR
select name from syscolumns where id=object_id('TableName') sKCGuw(mh
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。 $Q,n+ /
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 n%U9iwJ.
显示结果: UNY@w=]<
type vender pcs }1\?()rB
电脑 A 1 7CYH'DL
电脑 A 1 RhyegD
光盘 B 2 sx90lsu
光盘 A 2 |Rk37P{
手机 B 3 4Qhx[Hv>(
手机 C 3 aZC*7AK
23、说明:初始化表table1 T/5nu?v
TRUNCATE TABLE table1 *<CxFy;|
24、说明:选择从10到15的记录 !
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ty9rH=1
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三、技巧 9OhR41B
1、1=1,1=2的使用,在SQL语句组合时用的较多 r"1A`89
"where 1=1" 是表示选择全部 "where 1=2"全部不选, c_[ JjG^?P
如: XNK
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if @strWhere !='' L<"k7)k
begin M;> ha,x
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |H<|{{E
end {!g?d<*
else Xv]*;Bq:SK
begin <f[9j u
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +%x^ RV}
end 4KZ SL:A
我们可以直接写成 >5df@_'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )e#fj+>x)
2、收缩数据库 TLX^~W[gOm
--重建索引 7:ckq(89
DBCC REINDEX v7g
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DBCC INDEXDEFRAG h
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--收缩数据和日志 dkf}),Z F
DBCC SHRINKDB @<VG8{
DBCC SHRINKFILE ltP
3、压缩数据库 DwT i_8m;
dbcc shrinkdatabase(dbname) \v.HG]
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4、转移数据库给新用户以已存在用户权限 _82<|NN:
exec sp_change_users_login 'update_one','newname','oldname' D@2Ya/c
go ^CO#QnB @
5、检查备份集 ?TRW"%
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' mMga"I9
6、修复数据库 MyK^i2eD
ALTER DATABASE [dvbbs] SET SINGLE_USER -Zttj /K
GO G|<] Ma9x
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |F3vRt@
GO EmYO5Whi
ALTER DATABASE [dvbbs] SET MULTI_USER _dz+2au
GO [p2g_bI8yK
7、日志清除 Q1K"%
SET NOCOUNT ON S_`W@cp[
DECLARE @LogicalFileName sysname, 'o7R/`4KR
@MaxMinutes INT, `9]P/J^
@NewSize INT 'et(:}i
USE tablename -- 要操作的数据库名 q`h7H][(A
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ryz/rf
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]cS&8{ ^2
@NewSize = 1 -- 你想设定的日志文件的大小(M) IQo]9Lx
-- Setup / initialize s_x=^S3~LO
DECLARE @OriginalSize int Cb+P7[X-
SELECT @OriginalSize = size `6dy
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FROM sysfiles YAX #O\,
WHERE name = @LogicalFileName Y#GT*V
SELECT 'Original Size of ' + db_name() + ' LOG is ' + [>Ikitow
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + axHxqhO7zp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "[FCQ
FROM sysfiles 5ENov!$H
WHERE name = @LogicalFileName 4+BrTGp
CREATE TABLE DummyTrans C+}CU}
(DummyColumn char (8000) not null) 9)1P+c--
DECLARE @Counter INT, B b$S^F(Xq
@StartTime DATETIME, Rv0-vH.n
@TruncLog VARCHAR(255) ;:-}z.7Y
SELECT @StartTime = GETDATE(), ?S+/QyjcfJ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' p{+tFQy
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <m-Ni
EXEC (@TruncLog) R:SIs\%o
-- Wrap the log if necessary. kO
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired H0 {Mlu9
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aY3pvOV
AND (@OriginalSize * 8 /1024) > @NewSize s{b0#[
BEGIN -- Outer loop. >1_Dk7E0D
SELECT @Counter = 0 2l]C55p)s
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) :-W$PIBe
BEGIN -- update clij|?O
INSERT DummyTrans VALUES ('Fill Log') VGq{y{(
DELETE DummyTrans zS&7[:IRs'
SELECT @Counter = @Counter + 1 =>E44v
END (or =f`
EXEC (@TruncLog) qpH j4
END !NlB%cF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]W89.><%14
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + n=lggBRx
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' c80"8r
FROM sysfiles 11nO<WH
WHERE name = @LogicalFileName C@l +\M(
DROP TABLE DummyTrans Zw3hp,P]
SET NOCOUNT OFF s|Imz<IE
8、说明:更改某个表 {X{01j};8
exec sp_changeobjectowner 'tablename','dbo' %Z-Tb OX
9、存储更改全部表 e7)> U!9c9
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch z:@d@\$?
@OldOwner as NVARCHAR(128), +]aD^N9['
@NewOwner as NVARCHAR(128) VQZT.^
AS bQ${8ZO
DECLARE @Name as NVARCHAR(128) Udb0&Y1^
DECLARE @Owner as NVARCHAR(128) pO-)x:Wg
DECLARE @OwnerName as NVARCHAR(128) gDUoc*+h
DECLARE curObject CURSOR FOR s (l+{b &
select 'Name' = name, o(S^1j5
'Owner' = user_name(uid) B8P@D"u
from sysobjects Dg ?Ho2ih
where user_name(uid)=@OldOwner ?j},O=JFn
order by name {EiG23!qV
OPEN curObject }WBm%f
FETCH NEXT FROM curObject INTO @Name, @Owner {Tjtj@-
WHILE(@@FETCH_STATUS=0) 0
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BEGIN NK*:w *SOI
if @Owner=@OldOwner [qc6Q:
begin v=8~ZDY
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 72BzvY.
exec sp_changeobjectowner @OwnerName, @NewOwner _&8KB1~
end \, X?K
-- select @name,@NewOwner,@OldOwner DU*Hnii
FETCH NEXT FROM curObject INTO @Name, @Owner r' 97\|
END dqK
close curObject bN<O<x1j
deallocate curObject ~h~r]tV*+
GO MXu+I,y*
10、SQL SERVER中直接循环写入数据 f(zuRM^5
declare @i int =r@ie>*U
set @i=1 6.(]}?g1f
while @i<30 a'L7y%
begin dnhpWVhn
insert into test (userid) values(@i) f{oxF?|89
set @i=@i+1 hyr5D9d
end _^,[wD
小记存储过程中经常用到的本周,本月,本年函数 RvZryA*vu
Dateadd(wk,datediff(wk,0,getdate()),-1) 'ra_Zg[j
Dateadd(wk,datediff(wk,0,getdate()),6) OHXeqjhy
Dateadd(mm,datediff(mm,0,getdate()),0) `04Y ;@w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $4fjSSB~
Dateadd(yy,datediff(yy,0,getdate()),0) LOYyj?^7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) GO&R