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。 yLFZo"r
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一、基础 \}:RG^*m
1、说明:创建数据库 O8\> ?4)
CREATE DATABASE database-name }8lvi
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2、说明:删除数据库 1&7~.S;km
drop database dbname -=;V*;
3、说明:备份sql server _R/^P>Q?
--- 创建 备份数据的 device D6Q6yNE
USE master 5>S=f{ghFw
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' heizO",8.&
--- 开始 备份 --D&a;CO}
BACKUP DATABASE pubs TO testBack A,H|c="
4、说明:创建新表 _0GM!Cny
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) aB$xQ|~
根据已有的表创建新表: mKTa.
A:create table tab_new like tab_old (使用旧表创建新表) k_,wa]ws$
B:create table tab_new as select col1,col2... from tab_old definition only <]w(1{q(
5、说明:删除新表 Sh@en\m=#S
drop table tabname k'6Poz+<
6、说明:增加一个列 %jBI*WzR
Alter table tabname add column col type '!V5 #J
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。 (7zdbJX
7、说明:添加主键: Alter table tabname add primary key(col) 'gD,HX
说明:删除主键: Alter table tabname drop primary key(col) 1J{1>r
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?^X
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删除索引:drop index idxname ^i;y2c
注:索引是不可更改的,想更改必须删除重新建。 ezz;NH
9、说明:创建视图:create view viewname as select statement b'5]o
删除视图:drop view viewname dRhsnT+KX
10、说明:几个简单的基本的sql语句 \c1NIuJR
选择:select * from table1 where 范围 178u4$# b
插入:insert into table1(field1,field2) values(value1,value2) :6T8\W
删除:delete from table1 where 范围 AcoU.tpP
更新:update table1 set field1=value1 where 范围 iHYvH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |Q|vCWel{
排序:select * from table1 order by field1,field2 [desc] h=x{
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总数:select count as totalcount from table1 TXH9BlDn
求和:select sum(field1) as sumvalue from table1 g %e"K nU
平均:select avg(field1) as avgvalue from table1 Lh_Q@>k
最大:select max(field1) as maxvalue from table1 Qnr7Qnb
最小:select min(field1) as minvalue from table1 VX'cFqrK3
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11、说明:几个高级查询运算词 ?|$IZ9
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A: UNION 运算符 `@tnEg
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 !oxwA!
B: EXCEPT 运算符 Cg]Iz<<bE
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。
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C: INTERSECT 运算符 Nn:>c<[
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。 :~PzTUz
注:使用运算词的几个查询结果行必须是一致的。 cD 5^mxd%
12、说明:使用外连接 |to|kU
A、left outer join: I_aSC 4
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。 j34L*?
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 \v,mr|
B:right outer join: %=PGvu
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。 f8AgTw,K8
C:full outer join: 4k6,pt"
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。 =X24C'!Mpe
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二、提升 FCp\w1+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) wJ}9(>id*
法一:select * into b from a where 1<>1 m Bc2x8g)
法二:select top 0 * into b from a dH[T nqJn
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B098/`r
insert into b(a, b, c) select d,e,f from b; ;*AKeI2
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) [W*xPXr*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 i,R+C.6{
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. F,)\\$=,
4、说明:子查询(表名1:a 表名2:b) U%qE=u-
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) 3B^`xnV
5、说明:显示文章、提交人和最后回复时间 kCVO!@yZz
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b N5%Cwl6i
6、说明:外连接查询(表名1:a 表名2:b) Z{p)rscX
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?E2$
7、说明:在线视图查询(表名1:a ) F?jFFwim
select * from (SELECT a,b,c FROM a) T where t.a > 1; QVq+';cG
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 /t$J<bU
select * from table1 where time between time1 and time2 ch-.+p3
select a,b,c, from table1 where a not between 数值1 and 数值2 qVe&nXo
9、说明:in 的使用方法 0DQ\akh
select * from table1 where a [not] in ('值1','值2','值4','值6') >I&'Rj&Mc
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3{/Y&/\"'^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 6
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11、说明:四表联查问题: \[CPI`yQe
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 ..... C\RJ){dk
12、说明:日程安排提前五分钟提醒 '0MH-M
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Kc,=J?Ob
13、说明:一条sql 语句搞定数据库分页 i p"LoCE
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 yr"BeTrS.
14、说明:前10条记录 Q[Xh{B
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.) GyP.;$NHa[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =,HxtPJ
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 mDB?;a>
(select a from tableA ) except (select a from tableB) except (select a from tableC) :Y\!~J3W
17、说明:随机取出10条数据 J =j6rD
select top 10 * from tablename order by newid() !$1'q~sO
18、说明:随机选择记录 6!Z>^'6
select newid() p@Va`:RDW
19、说明:删除重复记录 -w3KBlo
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )B1gX>J\8
20、说明:列出数据库里所有的表名 %+F%C=GqI
select name from sysobjects where type='U' Yfa` }hQ
21、说明:列出表里的所有的 ^v+3qm@,
select name from syscolumns where id=object_id('TableName') M&q3xo"w
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 W81dLeTZg
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type grWmF3c#
显示结果: w /l\p3n
type vender pcs k&dLg5O
电脑 A 1 O3];1ud
电脑 A 1 1Bl;.8he.)
光盘 B 2 u}~j NV
光盘 A 2 k&M9Hn2
手机 B 3 |9&bkojo
手机 C 3 ]A%S&q
23、说明:初始化表table1 'Io2",~
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TRUNCATE TABLE table1 `COnb@uD
24、说明:选择从10到15的记录 >$ok3-tuU
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc a* GiLq
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三、技巧 Lo-\;%y
1、1=1,1=2的使用,在SQL语句组合时用的较多 iFBH;O_~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /'<Qk'
如: (t%+Z"j
if @strWhere !='' ^{+,j}V_H
begin !L|PDGD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere <^v-y)%N:A
end |OarE2
else T^F9A55y
begin LF?MO1!M
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' VQe@H8>3
end 7~H.\4HB
我们可以直接写成 DM[gjfMXu
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 23|R $s>}i
2、收缩数据库 |w)S
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--重建索引 l
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DBCC REINDEX 079mn/8;
DBCC INDEXDEFRAG "eOFp\vPr
--收缩数据和日志 G~$[(Fhk
DBCC SHRINKDB 6M-Y`T`J
DBCC SHRINKFILE 2z+-vT%
3、压缩数据库 JrA\ V=K
dbcc shrinkdatabase(dbname) Duh[(r_
4、转移数据库给新用户以已存在用户权限 _ giZ'&l!
exec sp_change_users_login 'update_one','newname','oldname' WJJwhr
go ~IIlCmMl,
5、检查备份集 7!r)[2l
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vf-cx\y7
6、修复数据库 9@{=2 k
ALTER DATABASE [dvbbs] SET SINGLE_USER c!20((2|I
GO !%,k]m'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Fmo^ ?~b
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER ^\Gukkmh}
GO ! {c"C
7、日志清除 Z7:TPY$b
SET NOCOUNT ON Z?AX
DECLARE @LogicalFileName sysname, bzh`s<+
@MaxMinutes INT, v[t*CpGd
@NewSize INT Q/u1$&1
USE tablename -- 要操作的数据库名 Bq
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 /~nPPC
@MaxMinutes = 10, -- Limit on time allowed to wrap log. %*Aq%,.={
@NewSize = 1 -- 你想设定的日志文件的大小(M) +w(>UBy-
-- Setup / initialize aH(B}wh{
DECLARE @OriginalSize int Y%"73.x
SELECT @OriginalSize = size }+3v5Nz;
FROM sysfiles p^/6Rb"e
WHERE name = @LogicalFileName #lo1GoL\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8H<:?D/tH
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Zwm2T3@e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [L4s.l_#
FROM sysfiles |WMP_sGn
WHERE name = @LogicalFileName `Ir{ax&H.e
CREATE TABLE DummyTrans sPoH12?AL
(DummyColumn char (8000) not null) =bDy :yY}
DECLARE @Counter INT, }2CVA.Qm!
@StartTime DATETIME, ?Gr2@,jlD
@TruncLog VARCHAR(255) IN#Z(FMVC
SELECT @StartTime = GETDATE(), = U)e_q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2F-
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^9wQl!e
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EXEC (@TruncLog) 8/oO}SLF
-- Wrap the log if necessary. l:?w{'i$
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired gxf{/EjH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %V2A}78
AND (@OriginalSize * 8 /1024) > @NewSize +D&aE$<
BEGIN -- Outer loop. [\ALT8vC?m
SELECT @Counter = 0 E%tGwbi7
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (I7s[
BEGIN -- update p#DJow
INSERT DummyTrans VALUES ('Fill Log') ,4`=gKn
DELETE DummyTrans oBqWIXM
SELECT @Counter = @Counter + 1 6OOdVS3\J
END XA4miQn&
EXEC (@TruncLog) CUG3C
END -w#*~Q{'*
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $Lx2!Zy
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Bk)*Z/1<x
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [<H'JsJl
FROM sysfiles |^!
WHERE name = @LogicalFileName GR ^d/
DROP TABLE DummyTrans \cKY{(E
SET NOCOUNT OFF wr+r J
8、说明:更改某个表 "S ~(|G
exec sp_changeobjectowner 'tablename','dbo' f:_mr zz
9、存储更改全部表 6r3.%V.&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch u:[vqlU
@OldOwner as NVARCHAR(128), $T%~t@Cv1
@NewOwner as NVARCHAR(128) `eXTVi|0"~
AS &Bfgvws;
DECLARE @Name as NVARCHAR(128) +*AdSzX
DECLARE @Owner as NVARCHAR(128) .W/#$s|X\
DECLARE @OwnerName as NVARCHAR(128) N# ?}r>W3
DECLARE curObject CURSOR FOR .{}=!>U2
select 'Name' = name, h:qt?$]J
'Owner' = user_name(uid) hI Q 2s
from sysobjects |2'u@<(Z/
where user_name(uid)=@OldOwner sH_5.+,`
order by name $wq[W,'#L
OPEN curObject <[W41{
FETCH NEXT FROM curObject INTO @Name, @Owner Jq8CII
WHILE(@@FETCH_STATUS=0) $MPh\T
BEGIN tITx+i
if @Owner=@OldOwner @_
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begin yR|Beno
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Mb0l*'ZF
exec sp_changeobjectowner @OwnerName, @NewOwner nz%{hMNYH
end zUNWcv!& "
-- select @name,@NewOwner,@OldOwner l%^VBv>
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FETCH NEXT FROM curObject INTO @Name, @Owner 0[SJ7k19
END S]#xG+$<
close curObject oMNgyAp^
deallocate curObject N u]&?
GO X_tc\}I]
10、SQL SERVER中直接循环写入数据 \f6@B:?y
declare @i int t<