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。 9yaTDxB>
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一、基础 )Ly~\*
1、说明:创建数据库 u80C>sQ
CREATE DATABASE database-name qM+Ai*q
2、说明:删除数据库 w]nt_xj
drop database dbname Bex;!1
3、说明:备份sql server 0U:X[2|)
--- 创建 备份数据的 device %|ClYr
USE master pL!,1D!
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <$K=3&:s8q
--- 开始 备份 p(nO~I2E
BACKUP DATABASE pubs TO testBack TspX7<6r
4、说明:创建新表 Na@;F{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) bI|{TKKN&P
根据已有的表创建新表: *JfGGI_E
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only QAt]sat
5、说明:删除新表 d3
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drop table tabname V)`A,7X
6、说明:增加一个列 P{9wJ<
Alter table tabname add column col type ,|A6l?iV
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 W -HOl!)
7、说明:添加主键: Alter table tabname add primary key(col) }EYmz/nN
说明:删除主键: Alter table tabname drop primary key(col) :5$ErI
8、说明:创建索引:create [unique] index idxname on tabname(col....) ID`Ot{ y
删除索引:drop index idxname ,A $IFE
注:索引是不可更改的,想更改必须删除重新建。 (F 9P1Iq
9、说明:创建视图:create view viewname as select statement rsa_)iBC
删除视图:drop view viewname ~JNE]mg
10、说明:几个简单的基本的sql语句 MgJ5FRQ
选择:select * from table1 where 范围 _KKux3a
插入:insert into table1(field1,field2) values(value1,value2) F(zCvT
删除:delete from table1 where 范围 ju3@F8AI
更新:update table1 set field1=value1 where 范围 o5 ~VT!'[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! w=<E)
排序:select * from table1 order by field1,field2 [desc] >2 #<tH0
总数:select count as totalcount from table1 S7WHOr9XMV
求和:select sum(field1) as sumvalue from table1 (n8?+GCa
平均:select avg(field1) as avgvalue from table1 )">#bu$
最大:select max(field1) as maxvalue from table1 Q)BSngW+
最小:select min(field1) as minvalue from table1 bcjh3WP
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11、说明:几个高级查询运算词 5z9hcQAS
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A: UNION 运算符 wr:W}Z@pL
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。 EC0B6!C&7
B: EXCEPT 运算符 )B+o
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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。 $GU s\
C: INTERSECT 运算符 ("PZ!z1m1
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 JP0aNu
注:使用运算词的几个查询结果行必须是一致的。 -^yc<%U
12、说明:使用外连接 fZr{x$]N0
A、left outer join: a%BC{XX
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。 /3k[3
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 m1jEky(
B:right outer join: E2dS@!]V
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。 lhJY]tQt/
C:full outer join: p7Zeudmj
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。 llR5qq=t
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二、提升 V`LE 'E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,mvFeo;@f
法一:select * into b from a where 1<>1 H)E,([
法二:select top 0 * into b from a g.Qn,l]X/p
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~PQR_?1
insert into b(a, b, c) select d,e,f from b; h lc!}{$%8
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) XUh&an$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ^ H2TSaJ;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. X]2Ib'(
4、说明:子查询(表名1:a 表名2:b) x9\{a
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) ==?%]ZE8
5、说明:显示文章、提交人和最后回复时间 FN/l/OSb
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b k$m'ebrS.~
6、说明:外连接查询(表名1:a 表名2:b) l l*g *zt3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +PWm=;tcC
7、说明:在线视图查询(表名1:a ) ~,};FI
select * from (SELECT a,b,c FROM a) T where t.a > 1; yK"\~t[@X:
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 Qi dI
select * from table1 where time between time1 and time2 [.Md_
select a,b,c, from table1 where a not between 数值1 and 数值2 bZgo}`o%
9、说明:in 的使用方法 L\"wz scn
select * from table1 where a [not] in ('值1','值2','值4','值6') zVtTv-DU
10、说明:两张关联表,删除主表中已经在副表中没有的信息 '_Pb\
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4clCZ@\K^
11、说明:四表联查问题: )'g4Ty
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 ..... J Q*~le*
12、说明:日程安排提前五分钟提醒 !Sy9v
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 3hBYx@jTO
13、说明:一条sql 语句搞定数据库分页 4IB`7QJq
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 n} !')r
14、说明:前10条记录 /Us+>vg!
select top 10 * form table1 where 范围 dc~vQDNw[X
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.) :N^B54o%6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )>b1%x} =
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 5N6R%2,A
(select a from tableA ) except (select a from tableB) except (select a from tableC) jt323hHth
17、说明:随机取出10条数据 fM:bXR2Y'
select top 10 * from tablename order by newid() kO^
18、说明:随机选择记录 [:e>FXV
select newid() y6sY?uu
19、说明:删除重复记录 Yz0HBEA
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -:L7iOzgD
20、说明:列出数据库里所有的表名 PIFZ '6gn
select name from sysobjects where type='U' R6>*n!*D@
21、说明:列出表里的所有的 [a$1{[|)
select name from syscolumns where id=object_id('TableName') H3d|eO4+W
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 K)`R?CZ:s
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type =? q&/
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显示结果: I|Hcs.uW
type vender pcs d/*EuJYin<
电脑 A 1 {[NQD3=+F
电脑 A 1 _f "I%QTL
光盘 B 2 :18}$
光盘 A 2 hZUS#75M5
手机 B 3 wV$V X
手机 C 3 P&5vVA6K7
23、说明:初始化表table1 #q0xlF@
TRUNCATE TABLE table1 d3T7$'l$
24、说明:选择从10到15的记录 kaR55
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p>pAU$k{O
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三、技巧 l{ fL~O
1、1=1,1=2的使用,在SQL语句组合时用的较多 SFsT^f<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, sZqi)lo-s
如: G~*R6x2g
if @strWhere !='' G8^b9xoA+.
begin 3+U2oI:I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X88I|Z'HIh
end r[j@@[)"
else Cd p_niF
begin !g>mjD
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5=8_Le
end hiR+cPSF
我们可以直接写成 l>HB 0o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &\/}.rF
2、收缩数据库 <_bGV
--重建索引 t`\l+L
DBCC REINDEX o1]1I9
DBCC INDEXDEFRAG E*9W'e~=
--收缩数据和日志 W`wT0kP?*]
DBCC SHRINKDB `wLmGv+V
DBCC SHRINKFILE 2V+[:>F
3、压缩数据库 g@>y`AFnr
dbcc shrinkdatabase(dbname) CFY4PuI"!
4、转移数据库给新用户以已存在用户权限 a[lx&CHgI
exec sp_change_users_login 'update_one','newname','oldname'
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go OW> >6zM
5、检查备份集 iqXsDgkr
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' tjm@+xs
6、修复数据库 FW<YN;
ALTER DATABASE [dvbbs] SET SINGLE_USER Gh'{O/F4*
GO :J5CmU$
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wLQM]$O
GO (%M:=zm
ALTER DATABASE [dvbbs] SET MULTI_USER 9 &Od7Cn
GO O}lqY?0*
7、日志清除 ! -gOqo
SET NOCOUNT ON ux7g%Q^"
DECLARE @LogicalFileName sysname, Qm?o^%a
@MaxMinutes INT, rIH+X2x
@NewSize INT mP)im]H
USE tablename -- 要操作的数据库名 o`ODz[04
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. y=}a55:qE
@NewSize = 1 -- 你想设定的日志文件的大小(M) mO\=#Q>
-- Setup / initialize a>nV!b\n5
DECLARE @OriginalSize int 9>5]y}.{
SELECT @OriginalSize = size E|B1h!!\c
FROM sysfiles 'BEM:1)
WHERE name = @LogicalFileName YjG:ECj}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + T=cb:PD{%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + nQ'AB~ Do
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !un_JZD
FROM sysfiles pQ+4++7ID
WHERE name = @LogicalFileName j%*<W> O
CREATE TABLE DummyTrans |:`gjl_Nf
(DummyColumn char (8000) not null) RAEiIf!3
DECLARE @Counter INT, _P]k6z+
@StartTime DATETIME, >Gxu8,_;
@TruncLog VARCHAR(255) @/?$ ZX/e[
SELECT @StartTime = GETDATE(), pM@0>DVi
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :3*0o3C/
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Bk1gE((
EXEC (@TruncLog) %5bN@XD
-- Wrap the log if necessary. HmEU;UbO-
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |<7nf7 5c}
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) zhde1JE
AND (@OriginalSize * 8 /1024) > @NewSize r\{; ~V
BEGIN -- Outer loop. &nF7CCF
SELECT @Counter = 0 K<Y-/t
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 7Rom#Kl:
BEGIN -- update _$4vk
INSERT DummyTrans VALUES ('Fill Log') /E6Tt
DELETE DummyTrans "{(4
SELECT @Counter = @Counter + 1 JE+{Vx}
END RD p(Ci
EXEC (@TruncLog) hLLg
END JSiLG0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + QGd"Z lQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + D&&11Iz&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' R:DW>LB
FROM sysfiles o//PlG~
WHERE name = @LogicalFileName T k>N4yq
DROP TABLE DummyTrans $yg}HS7HC
SET NOCOUNT OFF 30/(
8、说明:更改某个表 kv3jbSKCT
exec sp_changeobjectowner 'tablename','dbo' Q1@V?`rkS{
9、存储更改全部表 #9Dixsl*Q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }u..m$h
@OldOwner as NVARCHAR(128), 3&JsYQu
@NewOwner as NVARCHAR(128) K29KS)~;W
AS Ib8xvzR6I&
DECLARE @Name as NVARCHAR(128) 7: T 5P
DECLARE @Owner as NVARCHAR(128) BI6o@d;=4
DECLARE @OwnerName as NVARCHAR(128) ?en%m|}0
DECLARE curObject CURSOR FOR <:BhV82l
select 'Name' = name, +#y[sKa
'Owner' = user_name(uid) E>?T<!r~j
from sysobjects Tp/+{|~
where user_name(uid)=@OldOwner )zVD!eG_9
order by name 5gbJTh<JU
OPEN curObject n.Q?@\}2
FETCH NEXT FROM curObject INTO @Name, @Owner Y1vSwS%{T
WHILE(@@FETCH_STATUS=0) ]"M 4fA
BEGIN s?*MZC
if @Owner=@OldOwner A5gdZZ'x
begin C"ZCX6p+$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) eq\{*r"DCK
exec sp_changeobjectowner @OwnerName, @NewOwner O-vvFl#4
end kST
-- select @name,@NewOwner,@OldOwner R:v`\
FETCH NEXT FROM curObject INTO @Name, @Owner "I]% aK0
END yeNC-U<
close curObject 5ff66CRw
deallocate curObject # 1,(I
GO a4! AvG
10、SQL SERVER中直接循环写入数据 4o2C=?@(
declare @i int &sQtS
set @i=1 `W[oLQ
while @i<30 ]7^YPFc+
begin ef!V EtEOv
insert into test (userid) values(@i) BY$%gIB6>
set @i=@i+1 ,Tyh._sa
end ~Hs a6F&F
小记存储过程中经常用到的本周,本月,本年函数 ~z!U/QR2
Dateadd(wk,datediff(wk,0,getdate()),-1) NLC}XL
Dateadd(wk,datediff(wk,0,getdate()),6) !W8'apG&[
Dateadd(mm,datediff(mm,0,getdate()),0) rf8`|9h"7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "sRR:wzQu
Dateadd(yy,datediff(yy,0,getdate()),0) ( UV8M\
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) s?5(E}
上面的SQL代码只是一个时间段 p]#%e0
Dateadd(wk,datediff(wk,0,getdate()),-1) /\_ s
Dateadd(wk,datediff(wk,0,getdate()),6) #f@sq5pTO
就是表示本周时间段. z>hG'
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZuF-$]oL&
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) YXa^jFp
而在存储过程中 F/}PN1#T
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) jfHVXu^M
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) hC8'6h