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。 WV.hQX9P
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一、基础 7xv9v1['
1、说明:创建数据库 jhQoBC>:
CREATE DATABASE database-name ?z#*eoPr
2、说明:删除数据库 Fd\uTxykp
drop database dbname ]6[+tpx
3、说明:备份sql server 3CjixXaA$
--- 创建 备份数据的 device aG^E^^Y
USE master uJ
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9N'fU),I
--- 开始 备份 T+&fUhSy
BACKUP DATABASE pubs TO testBack p|2GPrA]aL
4、说明:创建新表 [B+F}Q^;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 6>rz=yAM_
根据已有的表创建新表: A1-,b.Ni
A:create table tab_new like tab_old (使用旧表创建新表) \
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B:create table tab_new as select col1,col2... from tab_old definition only T@U,<[,
5、说明:删除新表 BJWlx*U]
drop table tabname }7 +%k/
6、说明:增加一个列 5rB>)p05[
Alter table tabname add column col type k}H7bZug
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。 '~K]=JP
7、说明:添加主键: Alter table tabname add primary key(col) KFHZ3HZ:>
说明:删除主键: Alter table tabname drop primary key(col) _7Y-gy#\a
8、说明:创建索引:create [unique] index idxname on tabname(col....) =3QhGFd
删除索引:drop index idxname (b//YyqN
注:索引是不可更改的,想更改必须删除重新建。 ub-e! {
9、说明:创建视图:create view viewname as select statement FEu"b@v
删除视图:drop view viewname SfC* ZM}<
10、说明:几个简单的基本的sql语句 ||QK)$"
选择:select * from table1 where 范围 %p )"_q!ge
插入:insert into table1(field1,field2) values(value1,value2) cMZy~>
删除:delete from table1 where 范围 2SC-c `9)
更新:update table1 set field1=value1 where 范围 YR-G:-(#b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! h`\$8oV
排序:select * from table1 order by field1,field2 [desc] UHvA43
总数:select count as totalcount from table1 I<D7Jj
求和:select sum(field1) as sumvalue from table1 vLHn4>J,R
平均:select avg(field1) as avgvalue from table1 uK$ Xqo%L
最大:select max(field1) as maxvalue from table1 ~SBb2*ID
最小:select min(field1) as minvalue from table1 {{Ox%Zm
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11、说明:几个高级查询运算词 CO@G%1#
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A: UNION 运算符 trwQ@7
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。 EA>.SSs!
B: EXCEPT 运算符 >9A18xC
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。 C{85#`z`
C: INTERSECT 运算符 sED"}F)
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。 rP7
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注:使用运算词的几个查询结果行必须是一致的。 c86KDEF
12、说明:使用外连接 uq s
A、left outer join: !' ^l}K>
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。 4jebx
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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-=lt\?
B:right outer join: 7Qd$@ m
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 xH:L6K/c
C:full outer join: j}//e%$a
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。 ~9FL]qo
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二、提升 s=(q#Z
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) HL4=P,'
法一:select * into b from a where 1<>1 3pvqF,"~D
法二:select top 0 * into b from a 3{?X>6T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) s2SV
insert into b(a, b, c) select d,e,f from b; y4h
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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) N s0,Z#Z+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 "ymR8y'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 5s3QN{h8
4、说明:子查询(表名1:a 表名2:b) 4%~*}
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) >4luZnWMI
5、说明:显示文章、提交人和最后回复时间 XN Uw
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Q&r.wV|
6、说明:外连接查询(表名1:a 表名2:b) |Qcz5M90e
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 9&f+I@K
7、说明:在线视图查询(表名1:a ) CdRJ@Lf
select * from (SELECT a,b,c FROM a) T where t.a > 1; ?s$d("~
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 6WZffB{-TK
select * from table1 where time between time1 and time2 -V6caVlg
select a,b,c, from table1 where a not between 数值1 and 数值2 [%bGs1U
9、说明:in 的使用方法 EQ~<NzRp=
select * from table1 where a [not] in ('值1','值2','值4','值6') %50)?J=zB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 K0j%\]\Tp
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) G4SA
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11、说明:四表联查问题: wW*7
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 ..... 7ihcjyXB
12、说明:日程安排提前五分钟提醒 ^@* `vz^_
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 mTtaqo_Bh
13、说明:一条sql 语句搞定数据库分页 ;LP3
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 Wjl2S+Cc
14、说明:前10条记录 Dch\k<Te
select top 10 * form table1 where 范围 o0`']-)*2
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.) <`pNdy4
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) G$TO'Ciu:
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 p% mHxYP
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 ?{"r(
select top 10 * from tablename order by newid() VBi gUK4
18、说明:随机选择记录 k5aB|xo
select newid() o=7,U/{D!
19、说明:删除重复记录 6ScB:8M
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) GB Yy^wjU
20、说明:列出数据库里所有的表名 ph5{i2U0
select name from sysobjects where type='U' Y|r7gy9%
21、说明:列出表里的所有的 1!.-/
select name from syscolumns where id=object_id('TableName') dX/7n=
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。 I
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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 q{9 \hEeb
显示结果: $?W2'Xm!V
type vender pcs q}L`8(a
电脑 A 1 nX3?7"v
电脑 A 1 ?lD)J?j
光盘 B 2 `OMX 9i
光盘 A 2 b;jdk w|
手机 B 3 =AzPAN#e
手机 C 3 3A`]Rk
23、说明:初始化表table1 j8Z;}Ps
TRUNCATE TABLE table1 i#b /.oa
24、说明:选择从10到15的记录 I9G^T' W
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc tIDN~[1
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三、技巧 ni{'V4A
1、1=1,1=2的使用,在SQL语句组合时用的较多 H@@ 4n%MK
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \B~g5}=
如: ~;CNWJtcf(
if @strWhere !='' \ZADY.ha
begin q&z'S
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /lUfxc4
end F|>
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else V4jMx[
begin cX
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .%n_{ab1
end
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我们可以直接写成 #<[&Lw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere !0?o3,of-
2、收缩数据库 ^7+;XUyg
--重建索引 'u v=D
DBCC REINDEX 50Gr\
DBCC INDEXDEFRAG '(B -{}l
--收缩数据和日志 W
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DBCC SHRINKDB yC 1OeO8{
DBCC SHRINKFILE KJQ8Yhq
3、压缩数据库 Ll; v[Y
dbcc shrinkdatabase(dbname) RBf#5VjOG!
4、转移数据库给新用户以已存在用户权限 %Ve@DF8G
exec sp_change_users_login 'update_one','newname','oldname' nu+K
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go |#o' =whTl
5、检查备份集 VB*c1i
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 4Pc-A
6、修复数据库 %pq.fZI
ALTER DATABASE [dvbbs] SET SINGLE_USER G?$o+Y'F
GO xP'0a
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ty&1R?
GO YSGE@
ALTER DATABASE [dvbbs] SET MULTI_USER _Sd^/jGpU
GO ben-<3r
7、日志清除 ~xxq.rL"
SET NOCOUNT ON <e BmCrJ
DECLARE @LogicalFileName sysname, Cst>'g-yB
@MaxMinutes INT, Z@8amT;Y
@NewSize INT Z
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USE tablename -- 要操作的数据库名 n{Mj<\kL
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 (Qq$ql27
@MaxMinutes = 10, -- Limit on time allowed to wrap log. c(AjM9s
@NewSize = 1 -- 你想设定的日志文件的大小(M) &4DV]9+g
-- Setup / initialize h OboM3_
DECLARE @OriginalSize int qwaw\vOA
SELECT @OriginalSize = size 4p~:(U[q
FROM sysfiles (<.1o_Q-LU
WHERE name = @LogicalFileName +T^m
SELECT 'Original Size of ' + db_name() + ' LOG is ' + WiviH#hF
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + tZXtt=M w
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' xD1B50y U
FROM sysfiles ,?#-1uIGL>
WHERE name = @LogicalFileName n(f&uV_):
CREATE TABLE DummyTrans km<~Hw>Z
(DummyColumn char (8000) not null) 4'rk3nT8
DECLARE @Counter INT, );|~4#
@StartTime DATETIME, sX_ ^H%fd
@TruncLog VARCHAR(255) {@,
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SELECT @StartTime = GETDATE(), #lLL5ji
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) a5)[?ol
EXEC (@TruncLog) dadMwe_l0
-- Wrap the log if necessary. tc,7yo\".
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired X}usyO'pW
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) !6 $>|
AND (@OriginalSize * 8 /1024) > @NewSize $0W0+A$
BEGIN -- Outer loop. mifYk>J^9
SELECT @Counter = 0 .D>lv_kp
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |XH3$;=*h
BEGIN -- update <0LB]zDWe6
INSERT DummyTrans VALUES ('Fill Log') yauP j&^R
DELETE DummyTrans R&alq
SELECT @Counter = @Counter + 1 v S+~4Q41
END sw@2
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EXEC (@TruncLog) z~Pmh%b
END Jb$z(?S
SELECT 'Final Size of ' + db_name() + ' LOG is ' + p.}[!!m P
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' %!$-N!e
FROM sysfiles q}1$OsM
WHERE name = @LogicalFileName IGqmH=-
DROP TABLE DummyTrans 0Its;|
SET NOCOUNT OFF N^ET
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8、说明:更改某个表 jh?7+(Cw
exec sp_changeobjectowner 'tablename','dbo' SmLYxH3F
9、存储更改全部表 y-X'eCUz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch uHIWbF<0oo
@OldOwner as NVARCHAR(128), /g9{zR [
@NewOwner as NVARCHAR(128) w0I
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AS {pg@JA
DECLARE @Name as NVARCHAR(128) X}=f{/\S
DECLARE @Owner as NVARCHAR(128) J-f0
DECLARE @OwnerName as NVARCHAR(128) #&:nkzd
DECLARE curObject CURSOR FOR 7w$R-Y/E
select 'Name' = name, [uY2 Nh
'Owner' = user_name(uid) 7 r<>^j'
from sysobjects w${=dW@K
where user_name(uid)=@OldOwner C/vLEpP{(/
order by name JS:lysu
OPEN curObject D7(t6C=FP
FETCH NEXT FROM curObject INTO @Name, @Owner w+Z};C
WHILE(@@FETCH_STATUS=0) 2&d&$Jg
BEGIN MGz>
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if @Owner=@OldOwner Jqj6L993e
begin BT1'@qF
set @OwnerName = @OldOwner + '.' + rtrim(@Name) o'4@]ae
exec sp_changeobjectowner @OwnerName, @NewOwner 4Qo1f5>N
end B<&_lG0s