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。 j~(rG^T
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一、基础 RRqHo~*0
1、说明:创建数据库 )dbi
CREATE DATABASE database-name W^ict,t
2、说明:删除数据库 nKp='>Th
drop database dbname Vz!W(+
3、说明:备份sql server !krbGpTVH
--- 创建 备份数据的 device ce\]o^4
USE master p3`'i
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P}KN*Hn.
--- 开始 备份 5vj;lJKcd`
BACKUP DATABASE pubs TO testBack 57Q^"sl
4、说明:创建新表 TggM/@k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) IExo#\0'6
根据已有的表创建新表: SEq_37
A:create table tab_new like tab_old (使用旧表创建新表) -~~"}u
B:create table tab_new as select col1,col2... from tab_old definition only -tAdA2?G
5、说明:删除新表 mVg-z~44T
drop table tabname |G~LJsXW!v
6、说明:增加一个列 p [4/Nq,c
Alter table tabname add column col type BK]bSj
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。 n$g g$<
7、说明:添加主键: Alter table tabname add primary key(col) 1hw1AJ}(F
说明:删除主键: Alter table tabname drop primary key(col) aB;syl{
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q>] iRx>MZ
删除索引:drop index idxname ya0L8`q
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement TYGUB%A
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 qv y~b
选择:select * from table1 where 范围 Ci0: -IS
插入:insert into table1(field1,field2) values(value1,value2) "jH=O(37
删除:delete from table1 where 范围 "G-}
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更新:update table1 set field1=value1 where 范围 1-r#v
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L!Iu\_{q
排序:select * from table1 order by field1,field2 [desc] eEePK~%c
总数:select count as totalcount from table1 Fd*)1FQKT
求和:select sum(field1) as sumvalue from table1 <[ />M
平均:select avg(field1) as avgvalue from table1 Z|K+{{C
最大:select max(field1) as maxvalue from table1 j-8v$0'
最小:select min(field1) as minvalue from table1 M>VT$!Lx
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11、说明:几个高级查询运算词 "5"6mw?
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A: UNION 运算符 uo;aC$US
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。 l)<
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B: EXCEPT 运算符 IugYlt
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。 W+-a@)sh3Q
C: INTERSECT 运算符 4HQP,
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。 hqIYo
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注:使用运算词的几个查询结果行必须是一致的。 Kq@n BkO4
12、说明:使用外连接 Gx
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A、left outer join: `mXbF
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。 [`nY/g:
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 k
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B:right outer join: ;UTT>j
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。 17AJT
C:full outer join: wYQTG*&h
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。 mr
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二、提升 Q?-HU,RBO
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) p\T9q
法一:select * into b from a where 1<>1 2A7g}V
法二:select top 0 * into b from a qq"&Bc>
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 6FNs4|(d
insert into b(a, b, c) select d,e,f from b; ++d(}^C;
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) xdb9oH
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 wNMg Y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. AuuZWd
4、说明:子查询(表名1:a 表名2:b) <7N8L
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) qR^KvAEQSo
5、说明:显示文章、提交人和最后回复时间 z/6/
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {U1
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6、说明:外连接查询(表名1:a 表名2:b) >Y=HP&A<
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~SgW+sDFu
7、说明:在线视图查询(表名1:a ) tgXIj5z
select * from (SELECT a,b,c FROM a) T where t.a > 1; {j
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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 '2mR;APz
select * from table1 where time between time1 and time2 ~L $B]\/A5
select a,b,c, from table1 where a not between 数值1 and 数值2 _i{$5JJ+K2
9、说明:in 的使用方法 y`O !,kW
select * from table1 where a [not] in ('值1','值2','值4','值6') }1E'a>^|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 P=PcO>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) wQbN5*82
11、说明:四表联查问题: 2g5Ft
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 ..... ^HYmi\`
12、说明:日程安排提前五分钟提醒 UQ6UZd37
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 [ fvip_Pt
13、说明:一条sql 语句搞定数据库分页 D-\WS^#
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 "S#4
14、说明:前10条记录 ru[W?O"
select top 10 * form table1 where 范围 7zo)t1H1
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.) d\Cx(Lb[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :U)>um34e
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 [5K&J-W
(select a from tableA ) except (select a from tableB) except (select a from tableC) $MD|YW5
17、说明:随机取出10条数据 RU&,z3LEb
select top 10 * from tablename order by newid() Gh}k9-L
18、说明:随机选择记录 ?&$??r^i
select newid() 09z%y[z
19、说明:删除重复记录 7|4hs:4mD
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) QWVH4rg
20、说明:列出数据库里所有的表名 ;d$PQi
select name from sysobjects where type='U' v
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21、说明:列出表里的所有的 "{>I5<:t
select name from syscolumns where id=object_id('TableName') %"tLs%"7=P
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。 .2?txOKh
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 k[lYdk
显示结果: ^9*FYV
type vender pcs @8WG
电脑 A 1 0sq?;~U
电脑 A 1 `L p3snS
光盘 B 2 XQL"D)fw
光盘 A 2 Zwy8SD'L
手机 B 3 Sh'>5z2
手机 C 3 rmpx8CY"
23、说明:初始化表table1 k8fvg4
TRUNCATE TABLE table1 o=i)s2
24、说明:选择从10到15的记录 + E8\g
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc )6mx\t
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三、技巧 !z@QoD
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~5Wr
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, <hlH@[7!
如: Y"qKe,
if @strWhere !='' Uw R,U#d
begin ghvF%-."1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere DVCO(
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end ,4dES|)sP
else ?"MJ'u
begin 6<0-GD}M
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +g36,!q
end 'Okitq+O
我们可以直接写成 ! K? o H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere bz!9\D|h
2、收缩数据库 hKq <e%oVH
--重建索引 W\09hZ6
DBCC REINDEX j" wX7
DBCC INDEXDEFRAG YrAaL"20
--收缩数据和日志 T' O5>e
DBCC SHRINKDB OiPE,sv
DBCC SHRINKFILE RqTW$94RD
3、压缩数据库 Q*wub9
dbcc shrinkdatabase(dbname) Dw}8ci'
4、转移数据库给新用户以已存在用户权限 :$Lu
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exec sp_change_users_login 'update_one','newname','oldname' _r!''@B
go o6f^DG3*
5、检查备份集 w)I!q&`Y
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =6j4_+5mnH
6、修复数据库 LL,&!KW[S
ALTER DATABASE [dvbbs] SET SINGLE_USER s8w7/*<d
GO -:9E+b
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @ yJ/!9?^
GO fdr.'aMf%
ALTER DATABASE [dvbbs] SET MULTI_USER #PYTFB%
GO G<.p".o4
7、日志清除 GRpS^%8i@
SET NOCOUNT ON hpJ[VKe
DECLARE @LogicalFileName sysname, MGn:Gj"d
@MaxMinutes INT, O+Z[bis`
@NewSize INT h%e}4U@X
USE tablename -- 要操作的数据库名 yjCY2T E
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9G(.=aOj,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Hb&-pR@e\?
@NewSize = 1 -- 你想设定的日志文件的大小(M) `_{'qqRhe
-- Setup / initialize sW%U3,j
DECLARE @OriginalSize int G=4Da~<ij
SELECT @OriginalSize = size 3UeG>5R
FROM sysfiles J;+AG^U<
WHERE name = @LogicalFileName TbyQ'MbUv
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 5=CLR
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + F5Ce:+h
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' YpQ/ )fSEV
FROM sysfiles zjd]65P
WHERE name = @LogicalFileName =IBdnEz:M
CREATE TABLE DummyTrans <d$kGCz
(DummyColumn char (8000) not null) KA:>7-
DECLARE @Counter INT, >@^z?nb
@StartTime DATETIME, c_b^t09
@TruncLog VARCHAR(255) ?8wFT!J
SELECT @StartTime = GETDATE(), ]/;0
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <qH>[\
DBCC SHRINKFILE (@LogicalFileName, @NewSize) CL/8p;
EXEC (@TruncLog) _%Q\G,a;
-- Wrap the log if necessary. =L~,HS(l,
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired @]lKQZ^2&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) .E:QZH' M
AND (@OriginalSize * 8 /1024) > @NewSize ?! dp0<
BEGIN -- Outer loop. @Tmqw(n{
SELECT @Counter = 0 ` c~:3^?9d
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) :w_J/k5Zd
BEGIN -- update hNXP-s
INSERT DummyTrans VALUES ('Fill Log') e"en
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DELETE DummyTrans O?Xg%k#
SELECT @Counter = @Counter + 1 pK O\tkMJ
END vGWX= O
EXEC (@TruncLog) btb-MSkO
END V.J[Uwf
SELECT 'Final Size of ' + db_name() + ' LOG is ' + NC::;e
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + MNip;S_j
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' i}Ea>bi{N
FROM sysfiles w2y{3O"p=
WHERE name = @LogicalFileName KfJF9!U*?
DROP TABLE DummyTrans mMO:m8W
SET NOCOUNT OFF Cec!{]DL&
8、说明:更改某个表 YBQO]3f
exec sp_changeobjectowner 'tablename','dbo' N(mhgC<O
9、存储更改全部表 -[OGZP`8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *1iJa
@OldOwner as NVARCHAR(128), +GMM&6<
@NewOwner as NVARCHAR(128) K9
AS %Bg}
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DECLARE @Name as NVARCHAR(128) NwM =
DECLARE @Owner as NVARCHAR(128) -WP_0
DECLARE @OwnerName as NVARCHAR(128) u{=(]n
DECLARE curObject CURSOR FOR 0hcrQ^BB!b
select 'Name' = name, hBDPz1<
'Owner' = user_name(uid) {>>ozB.
from sysobjects p"ht|x
where user_name(uid)=@OldOwner [>#?C*s
order by name &s_O6cqgh
OPEN curObject `9b/Q
FETCH NEXT FROM curObject INTO @Name, @Owner k{Yj!C>
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WHILE(@@FETCH_STATUS=0) VR5$[-E3
BEGIN $Hqm 09w
if @Owner=@OldOwner S:{hgi,T*
begin [r_,BH\nu
set @OwnerName = @OldOwner + '.' + rtrim(@Name) m *8[I
exec sp_changeobjectowner @OwnerName, @NewOwner O?NAbxkp
end lwPK^)|}
-- select @name,@NewOwner,@OldOwner I"*g-ji0
FETCH NEXT FROM curObject INTO @Name, @Owner /HH5Mn*
END (qHI>3tpY
close curObject _7.Wz7 ]b
deallocate curObject Sai_rNRWB
GO 2;.7c+r0
10、SQL SERVER中直接循环写入数据 -fVeE<[
declare @i int lY!`<