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。 ?Xypn#OPt
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一、基础 9S]pC?N]E
1、说明:创建数据库 U U_0@V<
CREATE DATABASE database-name /=6_2t#vA
2、说明:删除数据库 qco'neR"z
drop database dbname # atq7tX
3、说明:备份sql server >]~581fYf
--- 创建 备份数据的 device Y0,{fw<
USE master 1sj7]G]`k
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' *b) (-#w3
--- 开始 备份 l.pxDMY
BACKUP DATABASE pubs TO testBack ~wW]ntZm
4、说明:创建新表 2Cp4aTGv#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Bn&P@C$7
根据已有的表创建新表: 8m
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A:create table tab_new like tab_old (使用旧表创建新表) ^;PjO|mD
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B:create table tab_new as select col1,col2... from tab_old definition only f<bB= 9J
5、说明:删除新表 cwzkA,e@
drop table tabname n>.@@
6、说明:增加一个列 h8UhrD<:
Alter table tabname add column col type u/j\pDl.
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Hu<]*(lK%
7、说明:添加主键: Alter table tabname add primary key(col) I(~([F2
说明:删除主键: Alter table tabname drop primary key(col) *bFWNJ}`q
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;F@Sz/
删除索引:drop index idxname Gxe)5,G
注:索引是不可更改的,想更改必须删除重新建。 i`F5
9、说明:创建视图:create view viewname as select statement :.g/=Q(T~
删除视图:drop view viewname 8` +=~S
10、说明:几个简单的基本的sql语句 o4FHR+u<M
选择:select * from table1 where 范围 ,byc!P
插入:insert into table1(field1,field2) values(value1,value2) <<d #
删除:delete from table1 where 范围 A Qjv?
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更新:update table1 set field1=value1 where 范围 R5=J :o
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yP$esDP
排序:select * from table1 order by field1,field2 [desc] (9%?ik
总数:select count as totalcount from table1 R&W%E%uj
求和:select sum(field1) as sumvalue from table1 bDWLHdu
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平均:select avg(field1) as avgvalue from table1 6Z#Nh@!+C
最大:select max(field1) as maxvalue from table1 30^q_|l:]
最小:select min(field1) as minvalue from table1 O.Pp*sQ^
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11、说明:几个高级查询运算词 _?"y1L.
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A: UNION 运算符 ^oPFLez56
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。 _=I1
B: EXCEPT 运算符 'hr_g* i
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。 M%ecWr!tj
C: INTERSECT 运算符 !8UIyw
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。 +C!GV.q[
注:使用运算词的几个查询结果行必须是一致的。 QYo04`Rl
12、说明:使用外连接 WZ?>F
A、left outer join: }TMO>eB'
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。 N@PwC(
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 p}pRf@(`\
B:right outer join: .S,E=
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。 ,4"N7_!7
C:full outer join: ^?Xs!kJP
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。 bxh-#x
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二、提升 |Yw k
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6inAnC@I
法一:select * into b from a where 1<>1 >C_G~R
法二:select top 0 * into b from a 3mU~G}ig
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) hev;M)t
insert into b(a, b, c) select d,e,f from b; `G!HGzVx;j
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) i=<;$+tW
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 cu>(;=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. }6a}8EyFP
4、说明:子查询(表名1:a 表名2:b) bEcN_7
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Mu/(Xp6 2
5、说明:显示文章、提交人和最后回复时间 :u9'ZHkZ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b DQ+6VPc^o
6、说明:外连接查询(表名1:a 表名2:b) xDw~n (*
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +:^l|6%}
7、说明:在线视图查询(表名1:a ) ep"{{S5g
select * from (SELECT a,b,c FROM a) T where t.a > 1; rGNa[1{kRs
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 _(g0$vRP~
select * from table1 where time between time1 and time2 15J"iN2"W
select a,b,c, from table1 where a not between 数值1 and 数值2 |
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9、说明:in 的使用方法 ?u:`?(\
select * from table1 where a [not] in ('值1','值2','值4','值6') ,!Q nh:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Zfk]Z9YO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pqO0M]}
11、说明:四表联查问题: "[7-1} l
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 ..... /v9qrZ$$
12、说明:日程安排提前五分钟提醒 NUVKAAgMX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4r4 #u'Om
13、说明:一条sql 语句搞定数据库分页 mhrF9&s
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 f@YdL6&d-
14、说明:前10条记录 AR( gI]1
select top 10 * form table1 where 范围 =| T ^)J
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.) jC[_uG
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )e5=<'f1
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 5QK%BiDlr
(select a from tableA ) except (select a from tableB) except (select a from tableC) kP$E+L
17、说明:随机取出10条数据 $=diG
select top 10 * from tablename order by newid() pnSKIn
18、说明:随机选择记录 kiJ=C2'&
select newid() :z P:4NW
19、说明:删除重复记录 swZi
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `w#VYs|k
20、说明:列出数据库里所有的表名 hK)'dG*
select name from sysobjects where type='U' Tk[]l7R~
21、说明:列出表里的所有的 nuWQ3w
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select name from syscolumns where id=object_id('TableName') QWa@?BO2p
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 dQSO8Jf
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 'V^M+ng
显示结果: v#{Nh8n
type vender pcs }=v4(M `%
电脑 A 1 ox`Zs2-a
电脑 A 1 eik_w(xPT
光盘 B 2 {.k IC@^O
光盘 A 2 [err$
手机 B 3 ?"
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手机 C 3 :(ql=+vDb4
23、说明:初始化表table1 s"#N;
TRUNCATE TABLE table1 A z@@0
24、说明:选择从10到15的记录 3.#L
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Qq.$!$
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三、技巧 2?%4|@*H?
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?bM%#x{e
"where 1=1" 是表示选择全部 "where 1=2"全部不选, I~F&@
如: 4|&/#Cz^Y
if @strWhere !='' Epp>L.?r
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /9kxDbj
end Bj4c_YBte
else ~l:Cj*6x8
begin e@VJ-s
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r3?8nQ$
end Z*w({k7]
我们可以直接写成 C ibfuR
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere } 'xGip@W
2、收缩数据库 ~SBW`=aP}
--重建索引 eCKm4l'BZ
DBCC REINDEX p_BG#dRM
DBCC INDEXDEFRAG zUJXA:L9
--收缩数据和日志 < w}i
DBCC SHRINKDB :tO?+1
DBCC SHRINKFILE t)8crX}P
3、压缩数据库 eD7\ ,}O
dbcc shrinkdatabase(dbname) S+KKGi_e
4、转移数据库给新用户以已存在用户权限 8*&-u +@%
exec sp_change_users_login 'update_one','newname','oldname' ha|2u(4
go XelFGT E
5、检查备份集 9$v\D3<Z
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9nQyPb6
6、修复数据库 z5({A2q
ALTER DATABASE [dvbbs] SET SINGLE_USER >DY/CcG\P
GO 4J,6cOuW4
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @>U9CL"
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER a9lYX*:
GO z|AknEE,
7、日志清除 < q(i(%
SET NOCOUNT ON ;(,GS@sP
DECLARE @LogicalFileName sysname, E l.eK9L
@MaxMinutes INT, Bz,D4E$
@NewSize INT pvt/{
USE tablename -- 要操作的数据库名 @.cord`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1G`5FU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. sR PQr?
@NewSize = 1 -- 你想设定的日志文件的大小(M) moVf(7
-- Setup / initialize </<z7V,{
DECLARE @OriginalSize int u]B
b ^[
SELECT @OriginalSize = size EX<1hAw
FROM sysfiles _`QME r?
WHERE name = @LogicalFileName ,agkV)H
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4ybOK~z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2\$<&]q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .-s!} P"
FROM sysfiles M[b~5L+S
WHERE name = @LogicalFileName T06w`'aL
CREATE TABLE DummyTrans -Bv1}xf=6
(DummyColumn char (8000) not null) bu]Se6%}
DECLARE @Counter INT, )Q/`o,Vm
@StartTime DATETIME, PFgjWp"Y
@TruncLog VARCHAR(255) *Ne2l`!1m
SELECT @StartTime = GETDATE(), fUKdC\WL
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >@"3Q`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o\;"|O}
EXEC (@TruncLog) ^^3va)1{!
-- Wrap the log if necessary. 4$DliP
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m3Z}eC8LK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) cW\Y?x
AND (@OriginalSize * 8 /1024) > @NewSize C"Q=(3
BEGIN -- Outer loop. q=%
C (
SELECT @Counter = 0 B "F`OS[
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Yn]yd1
BEGIN -- update I+j|'=M
INSERT DummyTrans VALUES ('Fill Log') vJAAAS
DELETE DummyTrans pMZf!&tM
SELECT @Counter = @Counter + 1 xgqv2s>L
END bo !]
EXEC (@TruncLog) C\^<v&
END YEPG[W<kg
SELECT 'Final Size of ' + db_name() + ' LOG is ' + mImbS)V
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Q()RO*9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~muIi#4
FROM sysfiles d7tD|[(J
WHERE name = @LogicalFileName | ]!Ky[P
DROP TABLE DummyTrans lPcVhj6No%
SET NOCOUNT OFF $aPHl
8、说明:更改某个表 ctUF/[_w;
exec sp_changeobjectowner 'tablename','dbo' &G@-yQ
9、存储更改全部表 ZDkD%SCy
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch MLD>"W
@OldOwner as NVARCHAR(128), m`\i+
@NewOwner as NVARCHAR(128) e(; `9T
AS ['4\O43yv
DECLARE @Name as NVARCHAR(128) n:^"[Le
DECLARE @Owner as NVARCHAR(128) JfP\7
DECLARE @OwnerName as NVARCHAR(128) _`X#c-J
DECLARE curObject CURSOR FOR @U
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select 'Name' = name, t3#H@0<
'Owner' = user_name(uid) U_}A{bFG
from sysobjects m!#)JFe67
where user_name(uid)=@OldOwner X!#i@V
order by name [
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OPEN curObject bDFCZH-:'O
FETCH NEXT FROM curObject INTO @Name, @Owner ? __aVQ7
WHILE(@@FETCH_STATUS=0) X#kjt)W
BEGIN igj={==m
if @Owner=@OldOwner !,6v=n[Nz
begin dp[w?AMhM9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 4I#eC#"
exec sp_changeobjectowner @OwnerName, @NewOwner C>:/(O
end Yf!*OGF
-- select @name,@NewOwner,@OldOwner J%\~<_2ny
FETCH NEXT FROM curObject INTO @Name, @Owner # +QWi0B
END SA(U D
close curObject \Sw+]pr~
deallocate curObject ;la#Vf:]
GO 7dlKdKH
10、SQL SERVER中直接循环写入数据 hM36QOdm
declare @i int $['7vcB^
set @i=1 &weY8\HD
while @i<30 r{q}f)
begin da00p-U
insert into test (userid) values(@i) pVV}1RDa
set @i=@i+1 ie$`pyj!x
end FM9X}%5nu9
小记存储过程中经常用到的本周,本月,本年函数 >9.5-5"
Dateadd(wk,datediff(wk,0,getdate()),-1) Y[iDX#
Dateadd(wk,datediff(wk,0,getdate()),6) "^9[OgE:
Dateadd(mm,datediff(mm,0,getdate()),0) F%PwIB~cy
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ];pf
Dateadd(yy,datediff(yy,0,getdate()),0) $c@w$2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) r)6uX
上面的SQL代码只是一个时间段 |%'6f}fnE
Dateadd(wk,datediff(wk,0,getdate()),-1) $>'" )7z
Dateadd(wk,datediff(wk,0,getdate()),6) GP[6nw_'^
就是表示本周时间段. S(>@:`=
下面的SQL的条件部分,就是查询时间段在本周范围内的: m feMmKFu\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) RHwaJ;:)#
而在存储过程中 |RR%bQ^{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) <$i"zb
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^s^JzFw