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。 u\G\KASUK%
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一、基础 k$} 6Qd
1、说明:创建数据库 ZsYT&P2
CREATE DATABASE database-name x68s$H
2、说明:删除数据库 ~#
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drop database dbname /d-7n|#E
3、说明:备份sql server ZpY"P6
--- 创建 备份数据的 device rk(0w|zR+
USE master FKB)o7
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rW3fd.;kss
--- 开始 备份
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BACKUP DATABASE pubs TO testBack ^zaN?0%S33
4、说明:创建新表 "A9 c]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) cb~m==G
根据已有的表创建新表: \>-%OcYlM
A:create table tab_new like tab_old (使用旧表创建新表) U
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B:create table tab_new as select col1,col2... from tab_old definition only mCx6$jz
5、说明:删除新表 tMy@'nj
drop table tabname $eBE pN
6、说明:增加一个列 7gQ~"Q
Alter table tabname add column col type V|fs"HY
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 \6${Na'\
7、说明:添加主键: Alter table tabname add primary key(col) c
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说明:删除主键: Alter table tabname drop primary key(col) n_*k
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8、说明:创建索引:create [unique] index idxname on tabname(col....) Nm=W?i
删除索引:drop index idxname pc%_:>
注:索引是不可更改的,想更改必须删除重新建。 1{V* (=Tp
9、说明:创建视图:create view viewname as select statement xTL"%'|
删除视图:drop view viewname SLc'1{
10、说明:几个简单的基本的sql语句 WChJ
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选择:select * from table1 where 范围 D*j\gI
插入:insert into table1(field1,field2) values(value1,value2) QRv2%^L
删除:delete from table1 where 范围 r
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更新:update table1 set field1=value1 where 范围 4m6E~_:F
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F
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排序:select * from table1 order by field1,field2 [desc] @YTZnGG*
总数:select count as totalcount from table1 Io&F0~Z;;(
求和:select sum(field1) as sumvalue from table1 j7 D\O
平均:select avg(field1) as avgvalue from table1 zW^@\kB0D
最大:select max(field1) as maxvalue from table1 NUH#
最小:select min(field1) as minvalue from table1 /P0%4aWu=
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11、说明:几个高级查询运算词 lH ^[b[
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A: UNION 运算符 UpS`KgF"v
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。 PGHl:4`Es!
B: EXCEPT 运算符 6l>$N?a
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 xGeRoW(X
C: INTERSECT 运算符 7m=tu?@
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 puz~Rfn#*
注:使用运算词的几个查询结果行必须是一致的。 JQ8wL _C>
12、说明:使用外连接 X}xy
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A、left outer join: /%U+kW
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 a ^b_&}y
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Bn/{J
B:right outer join: GV([gs
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 amIG9:-1'
C:full outer join: v>71?te
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 @DrMaTr
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二、提升 T)]5k3{
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) q8.K-"f(Q
法一:select * into b from a where 1<>1 MDS;qZx=
法二:select top 0 * into b from a 0>m-J
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) aQaO.K2
insert into b(a, b, c) select d,e,f from b; .4~n|d>z
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) \0m[Ch}~ey
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 70L{u+wIy
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. </|IgN$w`
4、说明:子查询(表名1:a 表名2:b) (&FSoe/!['
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) Cv|ya$}a
5、说明:显示文章、提交人和最后回复时间 Q%(LMq4UG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b W^q;=D6uh
6、说明:外连接查询(表名1:a 表名2:b) |[?"$g9v
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ".eD&oX{
7、说明:在线视图查询(表名1:a ) &/4W1=>(
select * from (SELECT a,b,c FROM a) T where t.a > 1; 'k#^Z
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
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select * from table1 where time between time1 and time2 %uyRpG3,
select a,b,c, from table1 where a not between 数值1 and 数值2 YZdp/X6x
9、说明:in 的使用方法 ^e>`ob
select * from table1 where a [not] in ('值1','值2','值4','值6') ]v3 9ag_hu
10、说明:两张关联表,删除主表中已经在副表中没有的信息 vO"Sy{)Z>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Z| Z447_
11、说明:四表联查问题: !t6:uC7H
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 ..... ZUb6d*B
12、说明:日程安排提前五分钟提醒 \&J7>vu^y
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s3W )hU)
13、说明:一条sql 语句搞定数据库分页 v3Y/D1jd"
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 *.AokY)_a
14、说明:前10条记录 4QZ -7_
select top 10 * form table1 where 范围 B8:_yAv o
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.) &'UYV>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) aO?(ZL
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/EfWwqt
(select a from tableA ) except (select a from tableB) except (select a from tableC) {SW}S_
17、说明:随机取出10条数据 Ym5q#f)|
select top 10 * from tablename order by newid() {
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18、说明:随机选择记录 T2
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select newid() _YY:}'+
19、说明:删除重复记录 *?K3jy{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) hp!UW
20、说明:列出数据库里所有的表名 ` ej
select name from sysobjects where type='U' # &o3[.)9
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') Kgi%Nd
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。 `(?E-~#'
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 wGE:U`
显示结果: Aq}]{gfQ1
type vender pcs _mKO4Atw
电脑 A 1 S,EXc^A7
电脑 A 1 -82Rz
光盘 B 2 zo&'2I
光盘 A 2 [ottUS@
手机 B 3 &)O X*y
手机 C 3 ._"U{
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23、说明:初始化表table1 ](4V3w.
TRUNCATE TABLE table1 ;OQ{
24、说明:选择从10到15的记录 9. Q;J#;1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (t1:2WY@
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三、技巧 ^$DpdzI
1、1=1,1=2的使用,在SQL语句组合时用的较多 s"<k)Xi
"where 1=1" 是表示选择全部 "where 1=2"全部不选, J_OIU#-B
如: el39HB$
if @strWhere !='' R 28v5
begin s!``OyI/Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b&B<'Wb
end SY_T\
}
else jm'(t=Ze
begin gd-4hR
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' /Ws@YP
end *;8tj5du
我们可以直接写成 &96I4su
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^wCjMi(sj
2、收缩数据库 PmO utYV
--重建索引 d>}pz
DBCC REINDEX W`K XO|'p@
DBCC INDEXDEFRAG r}MXXn,f
--收缩数据和日志 ` ZXX[&C
DBCC SHRINKDB (Kd;l&8
DBCC SHRINKFILE F`3c uL[N
3、压缩数据库 :bFmw dX
dbcc shrinkdatabase(dbname) abUvU26t
4、转移数据库给新用户以已存在用户权限 0#KDvCBJ
exec sp_change_users_login 'update_one','newname','oldname' J5}-5sV^
go pj G6v(zK
5、检查备份集 2f16 /0J@
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 7^#f<m;Ar!
6、修复数据库 eyy{z;D8r
ALTER DATABASE [dvbbs] SET SINGLE_USER E$; =*0w
GO oJbD|m
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wIz<Y{HA=
GO .a1WwI
ALTER DATABASE [dvbbs] SET MULTI_USER u{yENZ^P
GO [
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7、日志清除
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SET NOCOUNT ON hS}?"ST|
DECLARE @LogicalFileName sysname, [WnX'R R
@MaxMinutes INT, *fso6j#%
@NewSize INT (p'yya{(
USE tablename -- 要操作的数据库名 |\%[e@u
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 kMAQHpDD
@MaxMinutes = 10, -- Limit on time allowed to wrap log. nVko]y
@NewSize = 1 -- 你想设定的日志文件的大小(M) KlDW'R$
-- Setup / initialize uuHR!
DECLARE @OriginalSize int X90VJb]
SELECT @OriginalSize = size -z./6dQ
FROM sysfiles :TqvL'9o
WHERE name = @LogicalFileName QpwOrxI}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + t/LQ|/xo
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,J"6(nk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' EFu2&P
FROM sysfiles
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WHERE name = @LogicalFileName la>:%SD
CREATE TABLE DummyTrans ;BUJ5
(DummyColumn char (8000) not null) }20
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DECLARE @Counter INT, Uc%(#I]Mi
@StartTime DATETIME, H%>
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@TruncLog VARCHAR(255) YwyP+Sr\
SELECT @StartTime = GETDATE(), ~UX@%0%)N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0m$f9b|Q?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^AdHP!I
EXEC (@TruncLog) )1wC].RFYm
-- Wrap the log if necessary. 4eK!1|1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired im|(
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #\[h.4i
AND (@OriginalSize * 8 /1024) > @NewSize Q{T6t;eH
BEGIN -- Outer loop. 7T9m@
SELECT @Counter = 0 >Lx,<sE
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) q 9lz
BEGIN -- update ]l7) F-v
INSERT DummyTrans VALUES ('Fill Log') qZACX.Hw
DELETE DummyTrans =<R")D]4z
SELECT @Counter = @Counter + 1 %yX?4T;b
END bhDV U(%I6
EXEC (@TruncLog) 1Y4=D
END qPGpN0M`
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >UvLeS2h:y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + t+7h(?8L
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @^]wT_r
FROM sysfiles `&2~\o/
WHERE name = @LogicalFileName +>h}Uz
DROP TABLE DummyTrans {I0b%>r=
SET NOCOUNT OFF *F0O*n*7W
8、说明:更改某个表 g*?)o!_*
exec sp_changeobjectowner 'tablename','dbo' ~sT/t1Rp
9、存储更改全部表 &NZl_7PL
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =(:{>tO_"
@OldOwner as NVARCHAR(128), 0YK`wuZGS
@NewOwner as NVARCHAR(128) nXPl\|pXt
AS IV*@}~BJ
DECLARE @Name as NVARCHAR(128) al/Mgo
DECLARE @Owner as NVARCHAR(128) 9o5W\.A7[D
DECLARE @OwnerName as NVARCHAR(128) ?=,4{(/)
DECLARE curObject CURSOR FOR I.BsKB
select 'Name' = name, I[,tf!
'Owner' = user_name(uid) dCv@l7hE
from sysobjects cO/%;HEV
where user_name(uid)=@OldOwner e^2e[rp0
order by name 5SPhdpIg@[
OPEN curObject 5Z"IM8?
FETCH NEXT FROM curObject INTO @Name, @Owner uvR9BL2=
WHILE(@@FETCH_STATUS=0) JLo'=(
BEGIN ,PC'xrEo
if @Owner=@OldOwner IlQNo 1
begin ATx6YP@7~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) j06?Mm_c2
exec sp_changeobjectowner @OwnerName, @NewOwner z-};.!L^
end 6Y?%G>$6
-- select @name,@NewOwner,@OldOwner +c;/hM<IX.
FETCH NEXT FROM curObject INTO @Name, @Owner @a-u_|3q
END C_xOk'091
close curObject pa4,W!t
deallocate curObject zY_xJ"/9
GO W <.h@Rz+
10、SQL SERVER中直接循环写入数据 bW03m_<M<1
declare @i int ,{DZvif
set @i=1 XJJdCv^
while @i<30 gwVfiXR4
begin wMFo8;L
insert into test (userid) values(@i) n[DQ5l
set @i=@i+1 &D@/_m $
end :'1UX <&B
小记存储过程中经常用到的本周,本月,本年函数 +6paM
Dateadd(wk,datediff(wk,0,getdate()),-1) -+MGs]),
Dateadd(wk,datediff(wk,0,getdate()),6) XfY~q~f8
Dateadd(mm,datediff(mm,0,getdate()),0) N6K%Wkz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) X 'D ~#r
Dateadd(yy,datediff(yy,0,getdate()),0) $7M/rF;N5X
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~DY5`jV
上面的SQL代码只是一个时间段 O`Ht|@[6
Dateadd(wk,datediff(wk,0,getdate()),-1) CUJP"u>8M
Dateadd(wk,datediff(wk,0,getdate()),6) eyq\a'tyB
就是表示本周时间段. YbCqZqk
下面的SQL的条件部分,就是查询时间段在本周范围内的: ">pW:apl%
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) x~1.;dBF
而在存储过程中 T'YHV}b}vX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) WZ}je!82
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) HqM>K*XKU