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。 ~~I]SI k{
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一、基础 ~*Y/#kPY
1、说明:创建数据库 !<b+7A
CREATE DATABASE database-name \{ C
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2、说明:删除数据库 q^<;B Y
drop database dbname :R$v7{1
3、说明:备份sql server XIl#0-E0X
--- 创建 备份数据的 device {>TAnb?n
USE master x`'s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' v3kT~uv
--- 开始 备份 47A[-&y*X
BACKUP DATABASE pubs TO testBack j)juvat
4、说明:创建新表 57;(
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) s!Iinc^p
根据已有的表创建新表: h///
A:create table tab_new like tab_old (使用旧表创建新表) Mt%Q5^
B:create table tab_new as select col1,col2... from tab_old definition only I7t}$S6
5、说明:删除新表 Lw?>1rTT/
drop table tabname V|{~9^
6、说明:增加一个列 gI@nE:(m
Alter table tabname add column col type &b2@+/ F
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。 .v9i|E=<~
7、说明:添加主键: Alter table tabname add primary key(col) BrZ17
说明:删除主键: Alter table tabname drop primary key(col) ?,[$8V
8、说明:创建索引:create [unique] index idxname on tabname(col....) gb[.Ww
删除索引:drop index idxname \\d8ulu
注:索引是不可更改的,想更改必须删除重新建。 RtDTcaW/
9、说明:创建视图:create view viewname as select statement g|4>S<uC
删除视图:drop view viewname ^?0?*
10、说明:几个简单的基本的sql语句 %(s2{$3
选择:select * from table1 where 范围 ma"M? aM
插入:insert into table1(field1,field2) values(value1,value2) A v;NQt8ut
删除:delete from table1 where 范围 dKw[#(m5v
更新:update table1 set field1=value1 where 范围 %uo#<Ny/ I
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! c^5fhmlt
排序:select * from table1 order by field1,field2 [desc] twa H20
总数:select count as totalcount from table1 2&AX_#P
求和:select sum(field1) as sumvalue from table1 P;|63"U
平均:select avg(field1) as avgvalue from table1 V=Bmpg
最大:select max(field1) as maxvalue from table1 {`Mb ),G
最小:select min(field1) as minvalue from table1 )]m4FC:
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11、说明:几个高级查询运算词 )[yKO
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A: UNION 运算符 C?6q]k]r
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 -:b<~S[
B: EXCEPT 运算符 2t=&h|6EW
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 2{g&9
C: INTERSECT 运算符 {WeRFiQ?-
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 jX t5.9 t
注:使用运算词的几个查询结果行必须是一致的。 \oP
12、说明:使用外连接 ?b(DDQMf
A、left outer join: M,Lq4 bz
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 f.R;<V.)
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R m2M
B:right outer join: n~i^+pD@
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ;B:\e8
C:full outer join: .l,NmF9
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 *_ajb:
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二、提升 y35e3
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) CdtwR0
法一:select * into b from a where 1<>1 ^6!8)7b
法二:select top 0 * into b from a Lr`Gyl62
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) wvr`~ e
insert into b(a, b, c) select d,e,f from b; -W|~YK7e
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) [[ }ukG4
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 -,$:^4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. oiz]Bd
4、说明:子查询(表名1:a 表名2:b) 1 Va@w
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) li}>xDSQ4
5、说明:显示文章、提交人和最后回复时间 *r6v9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ZalL}?E
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6、说明:外连接查询(表名1:a 表名2:b) J %E0Wd
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c clIn}wQ
7、说明:在线视图查询(表名1:a ) X{h[
select * from (SELECT a,b,c FROM a) T where t.a > 1; D2\Ep L/
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 c&`]O\D-c
select * from table1 where time between time1 and time2 F-Ku0z]){?
select a,b,c, from table1 where a not between 数值1 and 数值2 eN m
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9、说明:in 的使用方法 KXu1%`x=%Z
select * from table1 where a [not] in ('值1','值2','值4','值6') XhOg>
10、说明:两张关联表,删除主表中已经在副表中没有的信息 mt-t8~A
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =]<X6!0mR
11、说明:四表联查问题: mDWRYIuN
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 ..... Y@b|/+
12、说明:日程安排提前五分钟提醒 4 %u\dTg/B
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 #"o`'5
13、说明:一条sql 语句搞定数据库分页 X8XE_VtP
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 2nSz0 .
14、说明:前10条记录 @,pn/[
select top 10 * form table1 where 范围 H\|H]: CE
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.) Jb8%A@Z+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q:Y`^jP
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 "m}N
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(select a from tableA ) except (select a from tableB) except (select a from tableC) m`@~ZIa?>B
17、说明:随机取出10条数据 ',6d0>4*
select top 10 * from tablename order by newid() xQqZi b5I
18、说明:随机选择记录 G4uOY?0N
select newid() 48mTL+*
19、说明:删除重复记录 ZYz8ul$E
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ;#7:}>}rO
20、说明:列出数据库里所有的表名 id/y_ekfP
select name from sysobjects where type='U' O*Z-3l
21、说明:列出表里的所有的 3E8 Gh>J_
select name from syscolumns where id=object_id('TableName') t0T#Xb
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 R>,_C7]u
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type '5 9{VA6h
显示结果: *
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type vender pcs c>#3{}X|x%
电脑 A 1 1EliR uJ
电脑 A 1 y*I,i*iv
光盘 B 2 : p7PiqQ
光盘 A 2 mxCqN1:#
手机 B 3 ' KNg;
手机 C 3 4}<[4]f?|
23、说明:初始化表table1 h;J%Z!Rjw
TRUNCATE TABLE table1 Oc/ i'
24、说明:选择从10到15的记录 F[0w*i&u5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc z+nq<%"'
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三、技巧 //^{u[lr
1、1=1,1=2的使用,在SQL语句组合时用的较多 /J&_ZDNV~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LT/*y=
如: 2:6lr4{uY
if @strWhere !='' I"WmDC`1
begin kM(,8j
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere qK&h$;~*y
end &LhR0A
else ,{#L i
begin -.UUa
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *47%|bf`
end +3-f$/po
我们可以直接写成 FF30VlJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /I0}(;^y
2、收缩数据库 %nj{eT
--重建索引 ->@iw!5xu
DBCC REINDEX eXtlqU$
DBCC INDEXDEFRAG H$)otDOE
--收缩数据和日志 #2qv"ntW
DBCC SHRINKDB 8fQXif\z
DBCC SHRINKFILE =o4McV}
3、压缩数据库 s&6/fa
dbcc shrinkdatabase(dbname) FW"gj\
4、转移数据库给新用户以已存在用户权限 ? UBE0C
exec sp_change_users_login 'update_one','newname','oldname' 5Yx
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go 257q%"
5、检查备份集 eg>]{`WQ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' oD%B'{Zs4
6、修复数据库 ztV%W6
ALTER DATABASE [dvbbs] SET SINGLE_USER ^FK-e;J
GO /6#i$\ j
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2S-z$Bi}]
GO h
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ALTER DATABASE [dvbbs] SET MULTI_USER OJ)XJL
GO Cvtz&dH
7、日志清除 C.hRL4+;Zm
SET NOCOUNT ON JE[J}-2
DECLARE @LogicalFileName sysname, !l1jQq_mK
@MaxMinutes INT, - !s=`9o
@NewSize INT j$khGR!
USE tablename -- 要操作的数据库名 f,8PPJ:,
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 e|.a%,Dcy
@MaxMinutes = 10, -- Limit on time allowed to wrap log. * l-F
@NewSize = 1 -- 你想设定的日志文件的大小(M) ++d[YhO
-- Setup / initialize ?4lEHef
DECLARE @OriginalSize int bU_P@GKB
SELECT @OriginalSize = size S| l%JM^
FROM sysfiles :n$?wp
WHERE name = @LogicalFileName $Q56~AP
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %Yny/O\e%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + lAPPng`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' G8OnNI
FROM sysfiles 8>ODtKI*
WHERE name = @LogicalFileName cu"ge]},
CREATE TABLE DummyTrans Wvwjj~HP2}
(DummyColumn char (8000) not null) jxDA+7
DECLARE @Counter INT, vOBXAF
@StartTime DATETIME, ^ V8?6E
@TruncLog VARCHAR(255) gqACIXR
SELECT @StartTime = GETDATE(), 3qwSm<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _S6SCSFc
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Xe<kdB3
EXEC (@TruncLog) rA1;DSw6E[
-- Wrap the log if necessary. 5OHF=wh
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Rj/ y.g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) O*hQP*Rs
AND (@OriginalSize * 8 /1024) > @NewSize J"yq)0
BEGIN -- Outer loop. @s~*>k#"#
SELECT @Counter = 0 v^1n.l %E
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4XArpKA
BEGIN -- update _t\)W(E&
INSERT DummyTrans VALUES ('Fill Log') 8fQaMn4V
DELETE DummyTrans E3h-?ugO'
SELECT @Counter = @Counter + 1 3 bll9Ey
END *vIC9./
EXEC (@TruncLog) z]=jer
END D?
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + uE,j$d
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e2MjV8Bs
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' QhmOO-Z?
FROM sysfiles Eilo;-El
WHERE name = @LogicalFileName tcj3x<
DROP TABLE DummyTrans hg}R(.1K=
SET NOCOUNT OFF 420yaw/":
8、说明:更改某个表 3("E5lI(g:
exec sp_changeobjectowner 'tablename','dbo' r[ RO"Ej"
9、存储更改全部表 -n`2>L1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch .7MLgC;
@OldOwner as NVARCHAR(128), Ox"SQ`nSj'
@NewOwner as NVARCHAR(128) %1%@L7wP>
AS 7B#HF?,?
DECLARE @Name as NVARCHAR(128)
@d6N[?3;
DECLARE @Owner as NVARCHAR(128) , @dhJ8/
DECLARE @OwnerName as NVARCHAR(128) j'nrdr6n
DECLARE curObject CURSOR FOR j+NpQ}t:
select 'Name' = name, !9. `zW"40
'Owner' = user_name(uid) %scQP{%aD
from sysobjects SSa0x9T
where user_name(uid)=@OldOwner ?E.MP7Y#V
order by name #%SF2PB;
OPEN curObject $O^U"
FETCH NEXT FROM curObject INTO @Name, @Owner t[b@P<F
WHILE(@@FETCH_STATUS=0) {DbWk>[DkG
BEGIN -owap-Va
if @Owner=@OldOwner h
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begin p$@l,4@{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !jyy`q=
exec sp_changeobjectowner @OwnerName, @NewOwner Rln@9muXA
end 'n!kqP
-- select @name,@NewOwner,@OldOwner R'p-
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FETCH NEXT FROM curObject INTO @Name, @Owner P(Q}r7F~(
END a
#Pr)H
close curObject o.KE=zp&z
deallocate curObject OiMr,
GO zr[|~-
10、SQL SERVER中直接循环写入数据 ,(&