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。 XZcsx
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一、基础 POH>!lHu
1、说明:创建数据库 7zr\AgV9
CREATE DATABASE database-name U`FybP2R~
2、说明:删除数据库 WeuV+}\b
drop database dbname '`"LX!"ZO
3、说明:备份sql server -_uL;9r
--- 创建 备份数据的 device *IGxa
USE master =d~]*[8
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' n8[sR;r5f
--- 开始 备份 x@DXW(
BACKUP DATABASE pubs TO testBack eno*JK
4、说明:创建新表 G&D N'bp
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X$/3
根据已有的表创建新表: \q3H#1A
A:create table tab_new like tab_old (使用旧表创建新表) GOJi/R.{
B:create table tab_new as select col1,col2... from tab_old definition only m80+b8b
5、说明:删除新表 \2_>$:UoV
drop table tabname edGV[=]F
6、说明:增加一个列 TzPx4L6?
Alter table tabname add column col type j`,;J[Zd`h
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。 Hxb{bF
7、说明:添加主键: Alter table tabname add primary key(col) C>v
说明:删除主键: Alter table tabname drop primary key(col) k%hD<_:p
8、说明:创建索引:create [unique] index idxname on tabname(col....) {Hp?rY@
删除索引:drop index idxname kjNA~{
注:索引是不可更改的,想更改必须删除重新建。 OOl{
9、说明:创建视图:create view viewname as select statement Da-F(^E
删除视图:drop view viewname kUP[&/Lc
10、说明:几个简单的基本的sql语句 Pdf_{8r
选择:select * from table1 where 范围 sB0+21'R
插入:insert into table1(field1,field2) values(value1,value2) cnLC> _hY
删除:delete from table1 where 范围 =#BeAsFfO
更新:update table1 set field1=value1 where 范围 ~e{2Y%
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *!Am6\+
排序:select * from table1 order by field1,field2 [desc] yp@mxI@1
总数:select count as totalcount from table1 $k'f)E
求和:select sum(field1) as sumvalue from table1 3Xd+>'H
平均:select avg(field1) as avgvalue from table1 NnHwk)'
最大:select max(field1) as maxvalue from table1 V]q{N-Iq
最小:select min(field1) as minvalue from table1 d.2b7q09
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11、说明:几个高级查询运算词 Vaha--QB
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A: UNION 运算符 v[Q)cqj/
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。 (R6ZoBZ
B: EXCEPT 运算符 E*(Q'p9C
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。 GGJ_,S*
C: INTERSECT 运算符 K"}Dbr
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。 \W=
注:使用运算词的几个查询结果行必须是一致的。 GK&yP%Z3
12、说明:使用外连接 So`xd
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A、left outer join: 2CmeO&(Qf*
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。 {_q2kk
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 46XB6z01
B:right outer join: N23s{S t
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。
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C:full outer join: MO _9Yi
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。 8z/ ^Ql
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二、提升 RLKO0 #
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) J&3;6I
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法一:select * into b from a where 1<>1 3M@>kIT8
法二:select top 0 * into b from a +uT=Wb \
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) W/\7m\B
insert into b(a, b, c) select d,e,f from b; Ix(4<s
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) dHp6G^Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 L1F){8[
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. vo::y"
4、说明:子查询(表名1:a 表名2:b) R=e`QMq
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) Q'8v!/"}p{
5、说明:显示文章、提交人和最后回复时间 ?-i|f_`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b c<H4rB
6、说明:外连接查询(表名1:a 表名2:b) 3zl!x
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_F v>>:
7、说明:在线视图查询(表名1:a ) 3/ [=
select * from (SELECT a,b,c FROM a) T where t.a > 1; KDXo9FzF
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 Iewq?s\Fo
select * from table1 where time between time1 and time2 wZC'BLD
select a,b,c, from table1 where a not between 数值1 and 数值2 '@fk(~|
9、说明:in 的使用方法 &>s(f-\8
select * from table1 where a [not] in ('值1','值2','值4','值6') AoR`/tr,
10、说明:两张关联表,删除主表中已经在副表中没有的信息 &a|oJ'clz
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) TM"-X\e~{
11、说明:四表联查问题: <=zGaU,
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 ..... #zy%B
12、说明:日程安排提前五分钟提醒 SHGO;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Fx@
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13、说明:一条sql 语句搞定数据库分页 :EO}uP2
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 r!M2H{
14、说明:前10条记录 |SxEJ
select top 10 * form table1 where 范围 7q\c\qL
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.) NNfCJ|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5G!X4%a
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 V`H#|8\i
(select a from tableA ) except (select a from tableB) except (select a from tableC) mi-\PD>X
17、说明:随机取出10条数据 I}q-J~s
select top 10 * from tablename order by newid() #E ~FF@a
18、说明:随机选择记录 =.o-R=:d
select newid() HAiUFO/R
19、说明:删除重复记录 TtvS|09p;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) E$1^}RGT)
20、说明:列出数据库里所有的表名 9:Y:Vx
select name from sysobjects where type='U' jqLyX
21、说明:列出表里的所有的 RhJ<<T.2
select name from syscolumns where id=object_id('TableName') D3K`b4YV
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 6
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type JxvwquI
显示结果: tS9m8(Hr%Q
type vender pcs
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电脑 A 1 H,I}R
电脑 A 1 :D,YR(])
光盘 B 2 ew"Fr1UGYZ
光盘 A 2 lvN{R{7>
手机 B 3 oby*.61?5l
手机 C 3 ;?[~]"
23、说明:初始化表table1 [a`i{(!
TRUNCATE TABLE table1 5{5ABV
24、说明:选择从10到15的记录 )s8r(.W
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc
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三、技巧 I,S'zHR
1、1=1,1=2的使用,在SQL语句组合时用的较多 |H A7 C
"where 1=1" 是表示选择全部 "where 1=2"全部不选, KF'M4P
如: &Ch)SD
if @strWhere !='' =I5XG"",
begin g\l;>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R#`itIYh
end Lg?'1dg
else ~h@tezF
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5_`}$"<~
end em]K7B=
我们可以直接写成 K$
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere gP<_DEd^`
2、收缩数据库 ,YY#ed&l
--重建索引 -hzza1DP
DBCC REINDEX 4
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DBCC INDEXDEFRAG Gw./qu-W
--收缩数据和日志 3/AUV%+
DBCC SHRINKDB .$k"+E
DBCC SHRINKFILE ZFON]$Zk
3、压缩数据库 l#"alU!<^
dbcc shrinkdatabase(dbname) Dr1F|[
4、转移数据库给新用户以已存在用户权限 yRYWx` G
exec sp_change_users_login 'update_one','newname','oldname' s]N-n?'G"
go j[fQs,efK
5、检查备份集 LnDj
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' QdTe!f|
6、修复数据库 AH`15k_i
ALTER DATABASE [dvbbs] SET SINGLE_USER </X"*G't
GO $imx-H`|
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ["F,|e{y$
GO _E;Y
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ALTER DATABASE [dvbbs] SET MULTI_USER r83~o/T@
GO !7oy%{L
7、日志清除 {X$Mwqhpp;
SET NOCOUNT ON
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DECLARE @LogicalFileName sysname, mig3.is
@MaxMinutes INT, X{
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@NewSize INT Ic}ofBK
USE tablename -- 要操作的数据库名 ~Hs{(7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 dO[4}FZ$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. gp)ds^
@NewSize = 1 -- 你想设定的日志文件的大小(M) `VsGa
-- Setup / initialize Lm|X5RVq
DECLARE @OriginalSize int X2[cR;;'
SELECT @OriginalSize = size KV_Ga8hs
FROM sysfiles @"8QG^q8de
WHERE name = @LogicalFileName !cb#fl
SELECT 'Original Size of ' + db_name() + ' LOG is ' + uE j6A
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + J7GsNFL
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' fYy.>m+P1
FROM sysfiles ^0Q*o1W
WHERE name = @LogicalFileName yxN!*~BvL
CREATE TABLE DummyTrans \zU5G#LQ
(DummyColumn char (8000) not null) JNaW>X$K
DECLARE @Counter INT, e_], O_Z
@StartTime DATETIME, .@Uz/j?>
@TruncLog VARCHAR(255) [MS.5+1Y
SELECT @StartTime = GETDATE(), [QbXj0en$
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' .Qt3!ek
DBCC SHRINKFILE (@LogicalFileName, @NewSize) gN(hv.nQ
EXEC (@TruncLog) <gLtX[v!CL
-- Wrap the log if necessary. 05B+WJ1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m;f?}z_\$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) YZRB4T9
AND (@OriginalSize * 8 /1024) > @NewSize wF8\
BEGIN -- Outer loop. j\f$r,4
SELECT @Counter = 0 *]WXM.R8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) LFyceFbm
BEGIN -- update od1omYsR
INSERT DummyTrans VALUES ('Fill Log') 1`lFF_stkP
DELETE DummyTrans ~,2hP
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SELECT @Counter = @Counter + 1 V^I/nuy
END o2 d~
EXEC (@TruncLog) suFOc
END #@^w>D6W
SELECT 'Final Size of ' + db_name() + ' LOG is ' + gF6j6
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lM^!^6=v0l
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' i@5%d!J
FROM sysfiles /\cu!yiX
WHERE name = @LogicalFileName oh~
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DROP TABLE DummyTrans _a$DY,;
SET NOCOUNT OFF ;Ia1L{472m
8、说明:更改某个表 HFuaoS+b*
exec sp_changeobjectowner 'tablename','dbo' MuV0;K\
9、存储更改全部表 SRN9(LN
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]t)M}^w
@OldOwner as NVARCHAR(128), * g4Cy8$
@NewOwner as NVARCHAR(128) ]A$^ l,
AS ^YJA\d@
DECLARE @Name as NVARCHAR(128) WWW#s gM%
DECLARE @Owner as NVARCHAR(128) { $/Fk6qr
DECLARE @OwnerName as NVARCHAR(128) >JPJ%~y
DECLARE curObject CURSOR FOR }.UI&UZ-
select 'Name' = name, O6,"#BX
'Owner' = user_name(uid) Hu8atlpo
from sysobjects F.pHL)37
where user_name(uid)=@OldOwner *}ee"eHs
order by name z-G7Y#
OPEN curObject Z,!Xxv;4
FETCH NEXT FROM curObject INTO @Name, @Owner 6BU0hV
WHILE(@@FETCH_STATUS=0) mqk(UOK`
BEGIN ' P`p.5nH
if @Owner=@OldOwner KV}U{s+U8
begin 19 wqDIE0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5A$az03y$\
exec sp_changeobjectowner @OwnerName, @NewOwner $;uWj|
end V/}>>4
-- select @name,@NewOwner,@OldOwner qzt2j\v
FETCH NEXT FROM curObject INTO @Name, @Owner I"32[?0
(;
END $Cd ;0gdv
close curObject nP\V1pgA
deallocate curObject DJYXC,r
GO QeeC2
10、SQL SERVER中直接循环写入数据 7Sz'vyiz
declare @i int >'-w%H/
set @i=1 6~h1iY_~
while @i<30 M1]6lg[si
begin YD46Z~$
insert into test (userid) values(@i) _8b]o~[Z+
set @i=@i+1 {IPn\Bka
end ;q,)NAr&
小记存储过程中经常用到的本周,本月,本年函数 bq3fiT9
Dateadd(wk,datediff(wk,0,getdate()),-1) BQ9`DYI b
Dateadd(wk,datediff(wk,0,getdate()),6) bI]UO)
Dateadd(mm,datediff(mm,0,getdate()),0) xcZ%,7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) M&djw`B
Dateadd(yy,datediff(yy,0,getdate()),0) TdP{{&'9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ?FV7|)f
上面的SQL代码只是一个时间段 dD^_^'i
Dateadd(wk,datediff(wk,0,getdate()),-1) j&[.2PW\
Dateadd(wk,datediff(wk,0,getdate()),6) u1)TG"+0
就是表示本周时间段. J4[x,(iq(
下面的SQL的条件部分,就是查询时间段在本周范围内的: / }XsuH
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) u@bOEcxK
而在存储过程中 =F%wlzF:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) J`+`Kq1T
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) hGA!1a4 c