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。 TbMlYf]It
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一、基础 6mZpyt
1、说明:创建数据库 2QHu8mFU
CREATE DATABASE database-name a"O9;&};&
2、说明:删除数据库 g7%vI8Y)@
drop database dbname ;rJ#>7K
3、说明:备份sql server OwC{ Ad{
--- 创建 备份数据的 device 'e))i#/VF
USE master w#(E+s~}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9MRe?
--- 开始 备份 {KqW<X6Hp
BACKUP DATABASE pubs TO testBack cCtd\/ \
4、说明:创建新表 g[2[
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #6AcM"
根据已有的表创建新表: H_JT"~_2
A:create table tab_new like tab_old (使用旧表创建新表) c1%ki%J#
B:create table tab_new as select col1,col2... from tab_old definition only Iq;a!Lya-
5、说明:删除新表 ({rescQB
drop table tabname .@(MNq{"6
6、说明:增加一个列 aj+I+r"~
Alter table tabname add column col type 1eqFMf
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。 YWhS< }^
7、说明:添加主键: Alter table tabname add primary key(col) RV5;EM)~[
说明:删除主键: Alter table tabname drop primary key(col) Y%rC\Ij/i
8、说明:创建索引:create [unique] index idxname on tabname(col....) %gEfG#S
删除索引:drop index idxname 5PHAd4=bJ
注:索引是不可更改的,想更改必须删除重新建。 p t{/|P
9、说明:创建视图:create view viewname as select statement ``?Z97rH
删除视图:drop view viewname G_p13{"IM
10、说明:几个简单的基本的sql语句 (P:.@P~
选择:select * from table1 where 范围 2L2)``*
插入:insert into table1(field1,field2) values(value1,value2) QEL3b4Vm
删除:delete from table1 where 范围 %}~Ncn_r
更新:update table1 set field1=value1 where 范围 `WU"*HqW
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9%Ftln6
排序:select * from table1 order by field1,field2 [desc] V,9UOC,Gn
总数:select count as totalcount from table1 @6DV?VL
求和:select sum(field1) as sumvalue from table1 ;@u+b0
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平均:select avg(field1) as avgvalue from table1 W^nG\"T^
最大:select max(field1) as maxvalue from table1 tdRnRoB
最小:select min(field1) as minvalue from table1 0j~C6vp
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11、说明:几个高级查询运算词 r`'n3#O*
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A: UNION 运算符 8BJ&"y8H
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。 ~); 7D'[
B: EXCEPT 运算符 RIl+QA
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。 q:v&wb%
C: INTERSECT 运算符 Co>=<\yi
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。 ?\Jl] {i2
注:使用运算词的几个查询结果行必须是一致的。 <yrl_vl{
12、说明:使用外连接 M>g\Y
A、left outer join: {*PB+WGe
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。 Y;XEC;PXD
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 *]
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B:right outer join: |P]>[}mD
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。 O}#h^AU-BS
C:full outer join: P\CT|K'P
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。 "o[j'
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二、提升 ebS>_jD
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +O@0gl
法一:select * into b from a where 1<>1 _6 |lw&o07
法二:select top 0 * into b from a 3 tp'}v
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) r6`v-TY(/
insert into b(a, b, c) select d,e,f from b; u>.qhtm[
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) !1}A\S
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 AA
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. y++[:M
4、说明:子查询(表名1:a 表名2:b) sc^TElic
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) 3X&}{M:Qo
5、说明:显示文章、提交人和最后回复时间 Xo>P?^c4?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b PSQ5/l?\>
6、说明:外连接查询(表名1:a 表名2:b) +idj,J|
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c G_~w0r#
7、说明:在线视图查询(表名1:a ) w#5^A(NR
select * from (SELECT a,b,c FROM a) T where t.a > 1; Vx^+Z,y&QP
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 h+!Ld^'c
select * from table1 where time between time1 and time2 bCF"4KXK
select a,b,c, from table1 where a not between 数值1 and 数值2 _kb
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9、说明:in 的使用方法 V\"x#uB
select * from table1 where a [not] in ('值1','值2','值4','值6') a8Jn.!
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :U>o;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) mh"&KX86W
11、说明:四表联查问题: shOQ/
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 ..... ;k<g#She
12、说明:日程安排提前五分钟提醒 '8v^.gZ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Q0I22?
13、说明:一条sql 语句搞定数据库分页 V&E)4KBOs
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 }^;Tt-*k
14、说明:前10条记录 +.T&U7xV
select top 10 * form table1 where 范围 wG4=[d
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.) HgP9evz,0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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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 e`fN+
(select a from tableA ) except (select a from tableB) except (select a from tableC) Y=l91dxGI
17、说明:随机取出10条数据 @JS O=8
select top 10 * from tablename order by newid() SNB>
18、说明:随机选择记录 v_PhJKE
select newid() Lf|5miO
19、说明:删除重复记录 E-_FxBw
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) s88lN=;
20、说明:列出数据库里所有的表名 f:gXXigY,
select name from sysobjects where type='U' w%&lCu@v
21、说明:列出表里的所有的 hmv"|1Sa!~
select name from syscolumns where id=object_id('TableName') Y#EM]x5!=
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。 #8G(r9
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 sG`:mc~0
显示结果: JJ5s
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type vender pcs U)%gzXTZ%
电脑 A 1 1H{M0e
电脑 A 1 [!B($c|\
光盘 B 2 !fXw X3B
光盘 A 2 i>w'$ {
手机 B 3 S+G!o]&2
手机 C 3 Ai&-W
23、说明:初始化表table1 Ly1V@
TRUNCATE TABLE table1 y<bA Y_-[
24、说明:选择从10到15的记录 V)CS,w
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (a0q*iC%
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三、技巧 i#o:V/Z.
1、1=1,1=2的使用,在SQL语句组合时用的较多 @0cQ4}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @Omgk=6
如: RM8p[lfX
if @strWhere !='' 7/nnl0u8
begin Nf(Np1?;c
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere
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end iq_y80g`8h
else BFP (2j
begin B -XM(Cj
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >CtT_yhx
end tJ>|t hk
我们可以直接写成 -I-u.!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rxZ%vzVQ>
2、收缩数据库 '|mVY; i[
--重建索引 Wy{xTLXk2
DBCC REINDEX ^.5`jdk
DBCC INDEXDEFRAG
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--收缩数据和日志 OU&eswW
DBCC SHRINKDB o RT<h
DBCC SHRINKFILE P%`|Tu!B
3、压缩数据库 WqX#T
dbcc shrinkdatabase(dbname) ]B'Ac%Rx
4、转移数据库给新用户以已存在用户权限 kigq(a
exec sp_change_users_login 'update_one','newname','oldname' X=O}k&
go ts
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5、检查备份集 ^fVLM>p <;
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' rv>K0= t0
6、修复数据库 3KFw0(S/
ALTER DATABASE [dvbbs] SET SINGLE_USER 2
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GO WVaIC $Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK xlQl1lOX
GO sU>!sxW
ALTER DATABASE [dvbbs] SET MULTI_USER H"hL+F ^
GO 0Y7b$~n'Y
7、日志清除 a xT-
SET NOCOUNT ON c5~d^
DECLARE @LogicalFileName sysname, ~9#nC`%2j
@MaxMinutes INT, x!$Dje}
@NewSize INT %si5cc?
USE tablename -- 要操作的数据库名 q^nSYp#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 rG7S^,5o
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4
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@NewSize = 1 -- 你想设定的日志文件的大小(M) \Kh@P*7
-- Setup / initialize y>+xdD0+
DECLARE @OriginalSize int -]=-IiC#
SELECT @OriginalSize = size yl63VX8w}
FROM sysfiles A)I4 `3E
WHERE name = @LogicalFileName V,>_L
SELECT 'Original Size of ' + db_name() + ' LOG is ' + nsChNwPX
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1S!<D)n
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' U'IJwGRP
FROM sysfiles `V N $
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WHERE name = @LogicalFileName ). +!/x
CREATE TABLE DummyTrans <.c@l,[.z
(DummyColumn char (8000) not null) v] *(Wd~|
DECLARE @Counter INT, "zJGYBen
@StartTime DATETIME, \L14rQ
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@TruncLog VARCHAR(255) r Ntc{{3_
SELECT @StartTime = GETDATE(), :UuPy|>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ^Pc>/lY$Q%
DBCC SHRINKFILE (@LogicalFileName, @NewSize) oYWcX9R
EXEC (@TruncLog) /$OX'L&b
-- Wrap the log if necessary. !oXA^7Th6]
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |.D_[QI
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) .hh2II
AND (@OriginalSize * 8 /1024) > @NewSize xJ"CAg|B
BEGIN -- Outer loop. 'TPRGX~&
SELECT @Counter = 0 o6e6Jw
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) x~."P*5
BEGIN -- update W68d"J%>_
INSERT DummyTrans VALUES ('Fill Log') @a.Y9;O
DELETE DummyTrans F\.n42Tz
SELECT @Counter = @Counter + 1 a7G0
END C7=Q!UK`\
EXEC (@TruncLog) V'h
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END *!De(lhEc
SELECT 'Final Size of ' + db_name() + ' LOG is ' + lu@#)
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + SfE^'G\
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' e=t?mDh#E
FROM sysfiles 5G8`zy
WHERE name = @LogicalFileName v | /IN
DROP TABLE DummyTrans ZIAiVq2)
SET NOCOUNT OFF zE VJ
8、说明:更改某个表 4+mawyM
exec sp_changeobjectowner 'tablename','dbo' S EY
9、存储更改全部表 Y^gK^?K
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "m]"%MU78
@OldOwner as NVARCHAR(128), /p')
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@NewOwner as NVARCHAR(128) u!2.[CV
AS qx5X2@-;:
DECLARE @Name as NVARCHAR(128) ~B%EvG7:n
DECLARE @Owner as NVARCHAR(128) 8|[\Tp:;
DECLARE @OwnerName as NVARCHAR(128) 9/w'4bd
DECLARE curObject CURSOR FOR x_Ki5~w5
select 'Name' = name, 5=Bj?xb$'
'Owner' = user_name(uid) r
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from sysobjects S=lA^#'UdX
where user_name(uid)=@OldOwner wxZnuCO%H8
order by name XKp %7;
OPEN curObject ?Gl'-tV
FETCH NEXT FROM curObject INTO @Name, @Owner =ox#qg.5
WHILE(@@FETCH_STATUS=0) ,TU!W|($
BEGIN 7|6tH@4Ub
if @Owner=@OldOwner UQ>GAzh
begin $X5~9s1Wl
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /#$bb4
exec sp_changeobjectowner @OwnerName, @NewOwner k=Ef)'
end u0$7k9mE
-- select @name,@NewOwner,@OldOwner X.s?=6}g
FETCH NEXT FROM curObject INTO @Name, @Owner f7X#cs)a
END tH:ea$A
close curObject 5S7`gN.
deallocate curObject ,@!8jar@w}
GO >4\V/
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10、SQL SERVER中直接循环写入数据 ]T^m>v)X
declare @i int P0Na<)\'Y!
set @i=1 #2DH_P
while @i<30 0s0[U
begin *ILS/`mdav
insert into test (userid) values(@i) &7Ixf?e!K
set @i=@i+1 r _xo>y~S
end Beqhe\{
小记存储过程中经常用到的本周,本月,本年函数 =&"Vf!7YR7
Dateadd(wk,datediff(wk,0,getdate()),-1) QY+#Vp<`
Dateadd(wk,datediff(wk,0,getdate()),6) f'FY<ed<w
Dateadd(mm,datediff(mm,0,getdate()),0) T<54qe4`p
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ~J<bwF
Dateadd(yy,datediff(yy,0,getdate()),0) w#F+rh3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) PR|Trnd&D
上面的SQL代码只是一个时间段 )[oU|!@
Dateadd(wk,datediff(wk,0,getdate()),-1) NH'RU`U)
Dateadd(wk,datediff(wk,0,getdate()),6) r
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就是表示本周时间段. 9,`mH0jP
下面的SQL的条件部分,就是查询时间段在本周范围内的: (dMFYL>YP
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )SA$hwR
而在存储过程中 A ws#>l<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1A E/ILGo
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) hQL9 Zl~