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。 0[}"b(O{
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一、基础 ~Bn#AkL
1、说明:创建数据库 +jzpB*@
CREATE DATABASE database-name OtJYr1:y_
2、说明:删除数据库 Sai_rNRWB
drop database dbname E,E:W uB
3、说明:备份sql server X4*{CM
--- 创建 备份数据的 device u9}}}UN!
USE master _={*<E
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ohusL9D
--- 开始 备份 [~?LOH
BACKUP DATABASE pubs TO testBack rP,i,1Ar 4
4、说明:创建新表 yd5r]6ej
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) HH+NNSRO
根据已有的表创建新表: #B:J7&@fn
A:create table tab_new like tab_old (使用旧表创建新表) ')I/D4v
B:create table tab_new as select col1,col2... from tab_old definition only `ysPEwA|
5、说明:删除新表 w(n&(5FzB<
drop table tabname -QCo]:cp
6、说明:增加一个列 eSoOJ[&$
Alter table tabname add column col type 9I=J#Hi|+
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。 HY9H?T
7、说明:添加主键: Alter table tabname add primary key(col) %yJL-6U
说明:删除主键: Alter table tabname drop primary key(col) UZMo(rG.]{
8、说明:创建索引:create [unique] index idxname on tabname(col....) j2deb`GD
删除索引:drop index idxname ja70w:ja
注:索引是不可更改的,想更改必须删除重新建。 "cRc~4%K
9、说明:创建视图:create view viewname as select statement ?/)Mt(p
删除视图:drop view viewname A{\7HV 5
10、说明:几个简单的基本的sql语句 fG;)wQJ
选择:select * from table1 where 范围 RfDIwkpp
插入:insert into table1(field1,field2) values(value1,value2) %Nd|VAe
删除:delete from table1 where 范围 a kgXI^K
更新:update table1 set field1=value1 where 范围 3lhXD_Y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ST)l0c+Y>
排序:select * from table1 order by field1,field2 [desc] o1MI&}r
总数:select count as totalcount from table1 j{>E.F2.
求和:select sum(field1) as sumvalue from table1 TbU\qcm]]
平均:select avg(field1) as avgvalue from table1 #>O,w0<qM
最大:select max(field1) as maxvalue from table1 )QaI{ z
最小:select min(field1) as minvalue from table1 KM< +9`
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11、说明:几个高级查询运算词 cQzd0X
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A: UNION 运算符 kf_s.Dedw
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。 >#*]/t
B: EXCEPT 运算符 'IFbD["r
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。 ~xGWL%og
C: INTERSECT 运算符 WW0N"m'
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。 Run)E*sf
注:使用运算词的几个查询结果行必须是一致的。 jWiZ!dtUZ
12、说明:使用外连接
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A、left outer join: LpaY Md;
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。 +VDwDJ)lG
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 V!3G\*$?
B:right outer join: cz
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 muT+H(Z p}
C:full outer join: K:z|1V
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ktU98Bk]
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二、提升 ?JzLn,&
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) M
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法一:select * into b from a where 1<>1 )M#~/~^f+
法二:select top 0 * into b from a >wej1#\3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <5@+:7Dv
insert into b(a, b, c) select d,e,f from b; /XEcA5C<
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) )AXTi4MNp
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {Mp>+e@xx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Ag }hyIl
4、说明:子查询(表名1:a 表名2:b) ^>h
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) (03m%\
5、说明:显示文章、提交人和最后回复时间 T mH#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9Vxsv*OR,
6、说明:外连接查询(表名1:a 表名2:b) _jy*`$"q(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c j,/OzVm9
7、说明:在线视图查询(表名1:a ) !\JG]2 \
select * from (SELECT a,b,c FROM a) T where t.a > 1; =:P9 $
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 ;Y?7|G97*S
select * from table1 where time between time1 and time2 D}HW7Hnu^
select a,b,c, from table1 where a not between 数值1 and 数值2 QL-((dZ<
9、说明:in 的使用方法 } !pC}m
select * from table1 where a [not] in ('值1','值2','值4','值6') E+dr\Xhv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 qXt2m
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Q5;Km1(
11、说明:四表联查问题: ~/!Zh
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 ..... *hF5cM[
12、说明:日程安排提前五分钟提醒 6NZ3(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qdCa]n!d
13、说明:一条sql 语句搞定数据库分页 >sm<
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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 p !AQ
14、说明:前10条记录 kR%CSLOVy
select top 10 * form table1 where 范围 :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.) ul(1)q^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZUQ1\Iw
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 n/pM[gI
(select a from tableA ) except (select a from tableB) except (select a from tableC) Kk!D|NKLC
17、说明:随机取出10条数据 +VdYT6{p
select top 10 * from tablename order by newid() 1e'-rm
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18、说明:随机选择记录 ym2\o_^(
select newid() rxI?|}4
19、说明:删除重复记录 ] \4-e2N`\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -F4CHpua
20、说明:列出数据库里所有的表名 -[~{c]/ c
select name from sysobjects where type='U' TA`*]*O(
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') /]>&OSV
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。 KB&t31aq
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 TqKL(Qw
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显示结果: H[*.Jd
type vender pcs 'hVOK(o0
电脑 A 1 .',ikez
电脑 A 1 c<A@Op"A
光盘 B 2 XsQ<yeun
光盘 A 2 X
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手机 B 3 gD _tBv
手机 C 3 UQPd@IVu6
23、说明:初始化表table1 [LL"86D
TRUNCATE TABLE table1 }qc[ysDK]
24、说明:选择从10到15的记录 )UI T'*ow
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc $*b>c:
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三、技巧 |I^\|5
1、1=1,1=2的使用,在SQL语句组合时用的较多 J^
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, ,
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如: m3F.-KPO
if @strWhere !='' feIAgd},
begin !g=,O6
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b\UQ6V
end H3QAIsGS
else | (v/>t
begin ,BW^j.7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]B3 0d
end 67 7p9{:
我们可以直接写成 #n{wK+lz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere vFL3eu#
2、收缩数据库 ~bigaY
--重建索引 #c+N}eX{
DBCC REINDEX O7s0M?4
DBCC INDEXDEFRAG a}M7"v9
--收缩数据和日志 +'uF3-+WY
DBCC SHRINKDB Tl8S|Rg
DBCC SHRINKFILE tI*u"%#t
3、压缩数据库 @o9EX }
dbcc shrinkdatabase(dbname) m?;)C~[
4、转移数据库给新用户以已存在用户权限 /:ma}qGy
exec sp_change_users_login 'update_one','newname','oldname' C0i: *1
go `USR]T_`
5、检查备份集 Ad@))o2
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *S~. KW [
6、修复数据库 B V+"uF
ALTER DATABASE [dvbbs] SET SINGLE_USER :Q+rEjw+
GO f@\
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1_7x'5GdA
GO >9+@oGe(E
ALTER DATABASE [dvbbs] SET MULTI_USER -T4?5T_
GO v}xz`]MW<,
7、日志清除 MA(\r
SET NOCOUNT ON }`5%2iG
DECLARE @LogicalFileName sysname, 4{CVBowi
@MaxMinutes INT, ;lW0p8
@NewSize INT P8DJv-f`
USE tablename -- 要操作的数据库名 T*k
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >AN`L`%2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. nHD4J;l
@NewSize = 1 -- 你想设定的日志文件的大小(M) nt "VH5
-- Setup / initialize D?@330'P9C
DECLARE @OriginalSize int 3t68cdFlz
SELECT @OriginalSize = size 0RtqqNFD
FROM sysfiles NjYpNd?g
WHERE name = @LogicalFileName e{To&gy~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^:{l~~9iKp
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4xtbP\=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 9y.C])(2
FROM sysfiles q6H90Zb
WHERE name = @LogicalFileName ,GVHwTZ0`
CREATE TABLE DummyTrans jTSw 0\}
(DummyColumn char (8000) not null) bi#o1jR
DECLARE @Counter INT, 9Hlu%R
@StartTime DATETIME, {s=QwZdR
@TruncLog VARCHAR(255) %9{4g->
SELECT @StartTime = GETDATE(), z[ z'.{;D
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' cU%#oEMf<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .s7o$u~l
EXEC (@TruncLog) e3)rF5pp
-- Wrap the log if necessary. ;oob
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;#`Z(A}
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) kRSu6r9
AND (@OriginalSize * 8 /1024) > @NewSize $qg5m,1?
BEGIN -- Outer loop. *bmk(%g
SELECT @Counter = 0 d cPh@3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *=@Z\]"?
BEGIN -- update '(^p$=3|@D
INSERT DummyTrans VALUES ('Fill Log') VI" ,E}
DELETE DummyTrans $'?CY)h{
SELECT @Counter = @Counter + 1 N5%~~JRO
END X*$ 7g;
EXEC (@TruncLog) zr8 4%_^
END 7 &GhJ^Ku
SELECT 'Final Size of ' + db_name() + ' LOG is ' + h^x7[qe
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + cCyg&% zsT
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $AG.<
FROM sysfiles -uy}]s5Qu
WHERE name = @LogicalFileName ;S,g&%N
DROP TABLE DummyTrans 5A~w_p*}
SET NOCOUNT OFF <(3Uu()
8、说明:更改某个表 .7~Kfm@2
exec sp_changeobjectowner 'tablename','dbo' if#$wm%
9、存储更改全部表 c?jjY4u
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Yk?uxZ4)H
@OldOwner as NVARCHAR(128), ;u}MG3Y8
@NewOwner as NVARCHAR(128) OSfwA&
AS la|#SS95
DECLARE @Name as NVARCHAR(128) PM%./
DECLARE @Owner as NVARCHAR(128) ^h^j:!76j
DECLARE @OwnerName as NVARCHAR(128) sE>'~+1_O
DECLARE curObject CURSOR FOR zs[t<`2
select 'Name' = name, ``aoLQc`
'Owner' = user_name(uid) /*rMveT
from sysobjects [h%_` 8z
where user_name(uid)=@OldOwner ?G!^|^S*
order by name FY#`]124*
OPEN curObject w$61+KH K
FETCH NEXT FROM curObject INTO @Name, @Owner 8ne5 B4
WHILE(@@FETCH_STATUS=0) 8b6:n1<fn
BEGIN 2z )h,<D
if @Owner=@OldOwner \f /<#'
begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) tH>%`:
exec sp_changeobjectowner @OwnerName, @NewOwner Jv7 @[<$
end %\:.rs^
-- select @name,@NewOwner,@OldOwner 4~Lw:o1a
FETCH NEXT FROM curObject INTO @Name, @Owner mN@0lfk;
END Pw$'TE}
close curObject , aawtdt/
deallocate curObject YdC:P#
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GO <@;e N&
10、SQL SERVER中直接循环写入数据 W=F?+KgL
declare @i int #i)h0ML/e
set @i=1 4I {|M,+
while @i<30 Y;-" Z
begin $t}L|"=8X
insert into test (userid) values(@i) *dUnP{6 g
set @i=@i+1 |6_<4lmTxF
end K")-P9I6-f
小记存储过程中经常用到的本周,本月,本年函数 m#%5H
Dateadd(wk,datediff(wk,0,getdate()),-1) d*q_DV
Dateadd(wk,datediff(wk,0,getdate()),6) 0{A VH/S
Dateadd(mm,datediff(mm,0,getdate()),0) 7p u*/W~
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &yVii^
Dateadd(yy,datediff(yy,0,getdate()),0) $XT&8%|*7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) "b -KVZ
上面的SQL代码只是一个时间段 CHBCi) '6h
Dateadd(wk,datediff(wk,0,getdate()),-1) J5|Dduv
Dateadd(wk,datediff(wk,0,getdate()),6) ly,d =
就是表示本周时间段. We9C9)0
下面的SQL的条件部分,就是查询时间段在本周范围内的: 2! &:V]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 173/A=]
而在存储过程中 PPE:@!u<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) o`G'E&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1j0yON