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。 k|
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一、基础 V:1_k"zQ
1、说明:创建数据库 :U'Oc3l#Y
CREATE DATABASE database-name c+UZ UgP
2、说明:删除数据库 ~fz9PoC
drop database dbname m=MM
3、说明:备份sql server - QQU>_
--- 创建 备份数据的 device }\EHZ
USE master ^
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' !7Z?VEZ
--- 开始 备份 stOD5yi
BACKUP DATABASE pubs TO testBack :j;_Xw
4、说明:创建新表 )oMMDHw\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) M` |E)Y
根据已有的表创建新表: lZD"7om
A:create table tab_new like tab_old (使用旧表创建新表) C)ebZ3
B:create table tab_new as select col1,col2... from tab_old definition only -$(2Z[
5、说明:删除新表 0C0ld!>r
drop table tabname ~*RBMHs
6、说明:增加一个列 l>@){zxL
Alter table tabname add column col type j.29nJ
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 gCW
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7、说明:添加主键: Alter table tabname add primary key(col) ujbJ&p
说明:删除主键: Alter table tabname drop primary key(col) ZJ|&t
8、说明:创建索引:create [unique] index idxname on tabname(col....) <{k8 K6
删除索引:drop index idxname Xm^/t#
注:索引是不可更改的,想更改必须删除重新建。 o 0H.DeP
9、说明:创建视图:create view viewname as select statement C.hRL4+;Zm
删除视图:drop view viewname JE[J}-2
10、说明:几个简单的基本的sql语句 !l1jQq_mK
选择:select * from table1 where 范围 - !s=`9o
插入:insert into table1(field1,field2) values(value1,value2) Y9nyKL
删除:delete from table1 where 范围 3x
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更新:update table1 set field1=value1 where 范围 NMhI0Ix$w
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *6]_ 6xO
排序:select * from table1 order by field1,field2 [desc] [vcSt5R=
总数:select count as totalcount from table1 uSNlI78D
求和:select sum(field1) as sumvalue from table1 8Y~\:3&1<
平均:select avg(field1) as avgvalue from table1 ~G8haN4
最大:select max(field1) as maxvalue from table1 *En4~;l
最小:select min(field1) as minvalue from table1 I<$m%
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11、说明:几个高级查询运算词 ZG_iF#
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A: UNION 运算符 >W=^>8u
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。 0|`iop%(n
B: EXCEPT 运算符 +(##B pC
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。 wRQMuFGY
C: INTERSECT 运算符 VJ|80?4h
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。 M7\K iQd
注:使用运算词的几个查询结果行必须是一致的。 wWB^m@:4
12、说明:使用外连接 \.{ZgL5"
A、left outer join: sm;\;MP*yH
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。 E>`gj~
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 Rj/ y.g
B:right outer join: O*hQP*Rs
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。 4d
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C:full outer join: @s~*>k#"#
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。 v^1n.l %E
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二、提升 lgh+\pj
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 3b1%^@,ACy
法一:select * into b from a where 1<>1 p|'Rm]&jb
法二:select top 0 * into b from a pL{:8Ed
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 5s1XO*s)>X
insert into b(a, b, c) select d,e,f from b; k\lU
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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) =42NQ{%@;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?bl9e&/!
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. B3V+/o6
4、说明:子查询(表名1:a 表名2:b) -^= JKd&p
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) $3{I'r]
5、说明:显示文章、提交人和最后回复时间 ,IQ%7*f;O_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b txemu*
6、说明:外连接查询(表名1:a 表名2:b) +cx(Q(HD\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2)jf~!o)Z
7、说明:在线视图查询(表名1:a ) N##-
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select * from (SELECT a,b,c FROM a) T where t.a > 1; (Ei} :6,}
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 MD=!a5'
select * from table1 where time between time1 and time2 cW\Y1=Gv|
select a,b,c, from table1 where a not between 数值1 and 数值2 &%` 0&y
9、说明:in 的使用方法 m7m)BX%O
select * from table1 where a [not] in ('值1','值2','值4','值6') p"=8{LrO
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .oxeo0@~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) z#{%[X2
11、说明:四表联查问题: K{]\}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 ..... 17B`
12、说明:日程安排提前五分钟提醒 ;2iDa
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]d50J@W
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13、说明:一条sql 语句搞定数据库分页 (,2U?p
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 _}:#T8h
14、说明:前10条记录 e^Glgaf
select top 10 * form table1 where 范围 Ky6 d{|H
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.) t%]b`ad
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) rb<9/z5-
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 dZ'H'm;,!
(select a from tableA ) except (select a from tableB) except (select a from tableC) c"^g*i2&0
17、说明:随机取出10条数据 xX2/uxi8
select top 10 * from tablename order by newid() F}=O Mo:.
18、说明:随机选择记录 ;v>+D
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select newid() K&/!3vc
19、说明:删除重复记录 ;q%V)4
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) PgwNE wG
20、说明:列出数据库里所有的表名 Z^ }4bR]
select name from sysobjects where type='U' QF9$SCmv
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') @y{
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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。 wxo{gBq
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 ueV,p?Wo
显示结果: 3\&I7o3V
type vender pcs cg'z:_l
电脑 A 1 7?"-NrW~
电脑 A 1 F)hUT@
光盘 B 2 8Hh=Sp^
光盘 A 2 1c}LX.9 K
手机 B 3 2+qU9[kd|
手机 C 3 ;>h:VnV(>(
23、说明:初始化表table1 J2Z?}5>
TRUNCATE TABLE table1 2M3C
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24、说明:选择从10到15的记录 C?lZu\L
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc uy
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三、技巧 '=]|"
1、1=1,1=2的使用,在SQL语句组合时用的较多 O*+,KKPt
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ]m"6a-,`
如: oAxCI/
if @strWhere !='' 4#2iq@s
begin 5WU?Km
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 7G 5VwO
end pl5Q2zq%
else @rt}z+JF
begin Lo^gg#o
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' <%EjrjdvL+
end C+X-Cp
我们可以直接写成 \4roM1&[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere u^]Z{K_B
2、收缩数据库 !:9s>0';N
--重建索引 Q[UYNQ0w
DBCC REINDEX X(fT[A_2C
DBCC INDEXDEFRAG _"'0^F$I
--收缩数据和日志 f
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DBCC SHRINKDB H"J>wIuGX
DBCC SHRINKFILE A6%~+9
3、压缩数据库 73>Hzpv0
dbcc shrinkdatabase(dbname) MFO1v%m
4、转移数据库给新用户以已存在用户权限 !DNk!]|
exec sp_change_users_login 'update_one','newname','oldname' V( SRw
go SH#!Y
5、检查备份集 ]8ob`F`m,
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' P~ 7p~ke
6、修复数据库 uT2w2A;
ALTER DATABASE [dvbbs] SET SINGLE_USER `Uy'YfYF
GO &Y|AX2KUC
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /F7X"_(H
GO vFgX]&bE
ALTER DATABASE [dvbbs] SET MULTI_USER '"fZGz?
GO w]=c^@t_
7、日志清除 rz]M}!>k
SET NOCOUNT ON \R (Yf!>
DECLARE @LogicalFileName sysname, /[#5<;
@MaxMinutes INT, ]sG^a7Z.X
@NewSize INT 2&d|L|->
USE tablename -- 要操作的数据库名 co [
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Onj)AJ9M0r
@MaxMinutes = 10, -- Limit on time allowed to wrap log. mUjM5ceAXO
@NewSize = 1 -- 你想设定的日志文件的大小(M) V[baGNe
-- Setup / initialize =Z}=n S?4
DECLARE @OriginalSize int +tvWp>T+
SELECT @OriginalSize = size =X}s^KbI{
FROM sysfiles zTS#o#`!\
WHERE name = @LogicalFileName 6`U]%qx_I
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Q<d|OX
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + -Gmg&yQ9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' n>i}O!agg
FROM sysfiles muKCCWy#
WHERE name = @LogicalFileName !0!r}#P
CREATE TABLE DummyTrans TwLQ;Q
(DummyColumn char (8000) not null) 7bC)Co#:
DECLARE @Counter INT, U#
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@StartTime DATETIME, XD$;K$_7
@TruncLog VARCHAR(255) ?N(opggiD
SELECT @StartTime = GETDATE(), ;J&9l
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <A@qN95m
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ul%D}(,
EXEC (@TruncLog) '(!U5j
-- Wrap the log if necessary. N(=\S:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 19 <Lgr
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +N:=|u.g
AND (@OriginalSize * 8 /1024) > @NewSize LGPPyKNx
BEGIN -- Outer loop. LQ3J$N
SELECT @Counter = 0 1JWo~E'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^P}c0}^
BEGIN -- update NG?- dkD
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans )ME'qA3K
SELECT @Counter = @Counter + 1 .l}oxWWoS
END "E}38
EXEC (@TruncLog) l"app]uVZ
END C}8 3t~Q
SELECT 'Final Size of ' + db_name() + ' LOG is ' + k~HS_b*]d
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + hz*H,E!>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles 8bI;xjK^Q
WHERE name = @LogicalFileName pA?2UZ
DROP TABLE DummyTrans +je{%,*
SET NOCOUNT OFF @]xHt&j
8、说明:更改某个表 J{h?=vK
exec sp_changeobjectowner 'tablename','dbo' @'fWS^ ;&
9、存储更改全部表 _8'z"wF
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _W^{,*p
@OldOwner as NVARCHAR(128), g]Fm%iy
@NewOwner as NVARCHAR(128) 8KyF0r?
AS d<+@cf_9
DECLARE @Name as NVARCHAR(128) {&d )O
DECLARE @Owner as NVARCHAR(128) `;\~$^sj}
DECLARE @OwnerName as NVARCHAR(128) ]0@
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DECLARE curObject CURSOR FOR lz88//@gZ
select 'Name' = name, fs;pX/:FR
'Owner' = user_name(uid) 4NxI:d$&*
from sysobjects a<d$P*I(cH
where user_name(uid)=@OldOwner YMD&U
order by name PWbi`qF)r
OPEN curObject N,~"8YSo
FETCH NEXT FROM curObject INTO @Name, @Owner %"g; K
WHILE(@@FETCH_STATUS=0) j#[%-nOT
BEGIN z((9vi W
if @Owner=@OldOwner )h,-zAnZ
begin T f;:C]
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 3}25=%;[
exec sp_changeobjectowner @OwnerName, @NewOwner sTChbks
end +#MQ8d
-- select @name,@NewOwner,@OldOwner fZF.eRP'
FETCH NEXT FROM curObject INTO @Name, @Owner Kb,#Ot
END G0&'B6I>
close curObject 6*tbil_G+
deallocate curObject >a$b4
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GO ,J ZM%f
10、SQL SERVER中直接循环写入数据 i$W
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declare @i int KmE<+/x~?
set @i=1 <9yB& ^
while @i<30 sm96Ye{O{
begin jhkNi`E7
insert into test (userid) values(@i) jO6yZt
set @i=@i+1 t o2y#4'.
end UgAG2
小记存储过程中经常用到的本周,本月,本年函数 %;qDhAu0
Dateadd(wk,datediff(wk,0,getdate()),-1) f$p7L.d<
Dateadd(wk,datediff(wk,0,getdate()),6) xA {1XS}
Dateadd(mm,datediff(mm,0,getdate()),0) )!jX$bK
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <Z^qBM
Dateadd(yy,datediff(yy,0,getdate()),0) fw+ VR.#2H
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V^ 5Z9!
上面的SQL代码只是一个时间段 "R9^X3;
Dateadd(wk,datediff(wk,0,getdate()),-1) {u_2L_
Dateadd(wk,datediff(wk,0,getdate()),6) 0f3C;u-q-
就是表示本周时间段. HC\\w-`<
下面的SQL的条件部分,就是查询时间段在本周范围内的: C8bv%9
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) W9%B9~\G;+
而在存储过程中 (D
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) n 9N'}z
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Y:'#jY*V