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。 I]j/ ab7>
dzC&7
9$
d$C|hT
一、基础 B7QtB3bn
1、说明:创建数据库 s9Q)6=mE
CREATE DATABASE database-name %BP)m(S7
2、说明:删除数据库 ^zs4tCW %
drop database dbname 2$/gg"g+
3、说明:备份sql server dJ"xW;"
--- 创建 备份数据的 device .TrQ +k>
USE master 1*Fvx-U'
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' QR-R5XNT[
--- 开始 备份 s%?p%2&RA
BACKUP DATABASE pubs TO testBack jnLo[Cf,H8
4、说明:创建新表 Bjrv;)XH
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lPSDY&`P
根据已有的表创建新表: i(qYyO'
A:create table tab_new like tab_old (使用旧表创建新表) C%7 ,#}[U/
B:create table tab_new as select col1,col2... from tab_old definition only 9/qS*Zdh)
5、说明:删除新表 %}AY0fg?T
drop table tabname V<R+A* gY:
6、说明:增加一个列 ~{tZ;YZ
Alter table tabname add column col type IgnY*2FT
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。 {w1h<;MH
7、说明:添加主键: Alter table tabname add primary key(col) >rX R;4%
说明:删除主键: Alter table tabname drop primary key(col) SbNU X
8、说明:创建索引:create [unique] index idxname on tabname(col....) @ %B!$\]
删除索引:drop index idxname sV4tu(~
注:索引是不可更改的,想更改必须删除重新建。 j`&i4K:
9、说明:创建视图:create view viewname as select statement ^Ypx|-Vu!
删除视图:drop view viewname +53zI|I
10、说明:几个简单的基本的sql语句 aGkVC*T
选择:select * from table1 where 范围 1H@rNam&
插入:insert into table1(field1,field2) values(value1,value2) )jZ=/xG
删除:delete from table1 where 范围 wjGjVTtHs
更新:update table1 set field1=value1 where 范围 HC`3AQ12!&
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8QgL7
排序:select * from table1 order by field1,field2 [desc] .2- JV0
总数:select count as totalcount from table1 &!EYT0=>p
求和:select sum(field1) as sumvalue from table1 ~0$F
V
平均:select avg(field1) as avgvalue from table1 pD.@&J~
最大:select max(field1) as maxvalue from table1 mZJzBYM)
最小:select min(field1) as minvalue from table1 3e<^-e)+xL
QZq9$;>dW
X!+ a;wr
,$(v#Tz
11、说明:几个高级查询运算词 T1]X
CoN/L`.SN
z7}zf@Y-qv
A: UNION 运算符 COJ!b
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。 Rm1` D
B: EXCEPT 运算符 CO+jB
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。 0\<-R
C: INTERSECT 运算符 r4>I?lD
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。 93eqFCF.
注:使用运算词的几个查询结果行必须是一致的。 p?NjxQLA
12、说明:使用外连接 L/+J|_J)
A、left outer join: JF\viMfR
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。 7%FZXsD
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 s5
'nWMo
B:right outer join: 5WN Z7cO
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。 ^"#rDP"v
C:full outer join: e{+{,g{iu
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。 @ BW8`Ky1
M HB]'
ZVR 9vw28
二、提升 |dzF>8< )
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,5"]K'Vce
法一:select * into b from a where 1<>1 ti2_kYq
法二:select top 0 * into b from a "8
mulE,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @{a-IW3
insert into b(a, b, c) select d,e,f from b; _Cs}&Bic_
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) T/6=A$4
#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 TmZ[?IL,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !27]1%Aw
4、说明:子查询(表名1:a 表名2:b) U:jf9L2
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) h4i$z-!
5、说明:显示文章、提交人和最后回复时间 ;i?!qB>baX
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Cb-E<W&2D
6、说明:外连接查询(表名1:a 表名2:b) odn`%ok
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c vaZZzv{H
7、说明:在线视图查询(表名1:a ) m
=F@CA~C
select * from (SELECT a,b,c FROM a) T where t.a > 1; =eLb"7C#0
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 OYy !4Fp
select * from table1 where time between time1 and time2 'U0I.x(
select a,b,c, from table1 where a not between 数值1 and 数值2 ng*E9Puu[
9、说明:in 的使用方法 A:J{
select * from table1 where a [not] in ('值1','值2','值4','值6') Xkm2C)
10、说明:两张关联表,删除主表中已经在副表中没有的信息 -d)n0)9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) u@'zvkb@
11、说明:四表联查问题: A+DYIS
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 ..... X&8,.=kt"
12、说明:日程安排提前五分钟提醒 `R?W @,@'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 sB/s17ar
13、说明:一条sql 语句搞定数据库分页 p>O< "X@
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 X1dG'PQ
14、说明:前10条记录 GP'Y!cl
select top 10 * form table1 where 范围 :vT%5CQ
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.) 6x{IY
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) l!` 0I] }
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 *
XGBym
(select a from tableA ) except (select a from tableB) except (select a from tableC) e!Okc*,
17、说明:随机取出10条数据 W-QPO
select top 10 * from tablename order by newid() X5<.%@Z
18、说明:随机选择记录 93DBZqN
select newid() n"Vd"}sU.
19、说明:删除重复记录 XOU$3+8q5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ]w_)Spo.
20、说明:列出数据库里所有的表名 c/U6K
yiK
select name from sysobjects where type='U' @v=q,A8_
21、说明:列出表里的所有的 fMaNv6(
select name from syscolumns where id=object_id('TableName') NyLnE
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 loe>"_`Cq
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type lM"7 Z
显示结果: c`; LF'!
type vender pcs d~8~RT2m
电脑 A 1
RZ%X1$
电脑 A 1 A$6b=2hc>
光盘 B 2 PlUjjJU
光盘 A 2 mkA|gM[g7
手机 B 3 7# 3)&"j
手机 C 3 D:EF@il
23、说明:初始化表table1 )c !S@Hs
TRUNCATE TABLE table1 GA}^Rh`T-
24、说明:选择从10到15的记录 VC7F#a*V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kc[["w&
&Qjl|2
-P&e4sV{
L{pg?#\yC
三、技巧 oy: MM
1、1=1,1=2的使用,在SQL语句组合时用的较多 2&URIQg*J
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #{,IY03
如: V/e_:xECC
if @strWhere !='' ]L^M7SKE6
begin w%n]~w=8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,2bAKa
end H/Q)zDP
else i@L2W>{P
begin o hlVc%a
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' I|z#Aoc
end 0 XzO`*
我们可以直接写成 -~f.>@Wb
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y cpO;md
2、收缩数据库 7bS[\5
--重建索引 pnJT]?},
DBCC REINDEX qTF>!o#\:
DBCC INDEXDEFRAG 3PffQ,c[~
--收缩数据和日志 Z+(V \
DBCC SHRINKDB xltu
g##
DBCC SHRINKFILE "mK (?U!A
3、压缩数据库 S I5QdX
dbcc shrinkdatabase(dbname) Bx4GFCdifC
4、转移数据库给新用户以已存在用户权限 ]E^f8s0#V
exec sp_change_users_login 'update_one','newname','oldname' U^\~{X
go BH a>2N
5、检查备份集 6QQ oHYtZ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <vDm(-i3
6、修复数据库 ?%Fk0E#>2
ALTER DATABASE [dvbbs] SET SINGLE_USER w}q"y+=Z:
GO =:eE!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK z?[DW*
GO k)Wz b
ALTER DATABASE [dvbbs] SET MULTI_USER F DX+
GO @x
+#ZD(
7、日志清除 /
u6$M/Cf>
SET NOCOUNT ON <Q)}
DECLARE @LogicalFileName sysname, F-0PmO~3+W
@MaxMinutes INT, or`stBx
@NewSize INT |'_<(z
USE tablename -- 要操作的数据库名 [rU8
#4.
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 89mre;v`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )n@ 3@NV
@NewSize = 1 -- 你想设定的日志文件的大小(M) q(^J7M)
-- Setup / initialize MGDv4cFE.
DECLARE @OriginalSize int Ms)zEy>[Ql
SELECT @OriginalSize = size TVwYFX
FROM sysfiles "s9gQAoaO
WHERE name = @LogicalFileName V}+;bbUc-
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Y'1V(5/&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + yG$@!*|
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' : PkZ(WZ9
FROM sysfiles 8f5^@K\c
WHERE name = @LogicalFileName wkA!Jv%
CREATE TABLE DummyTrans _Qc\v0%
(DummyColumn char (8000) not null) #HYkzjb
DECLARE @Counter INT, ?GU!ke p
@StartTime DATETIME, 3HR]T Q%r
@TruncLog VARCHAR(255) QPE.b-S
SELECT @StartTime = GETDATE(), );H[lKy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >nEnX
DBCC SHRINKFILE (@LogicalFileName, @NewSize) s;$TX30 4
EXEC (@TruncLog) [)vwg`]
-- Wrap the log if necessary. Cq;d2u0)o$
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w[YbL2p
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ygt)7f5
AND (@OriginalSize * 8 /1024) > @NewSize >]8.xkQq
BEGIN -- Outer loop. 4LJ}>e
SELECT @Counter = 0 X{9o8
*V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) /j@ `aG(a
BEGIN -- update tta0sJ8i
INSERT DummyTrans VALUES ('Fill Log') tdF[2@?+
DELETE DummyTrans F:GKnbY
SELECT @Counter = @Counter + 1 ;@~*z4U
END :Xh`.*{EX
EXEC (@TruncLog) |9$'?4F
END 5V8C+k)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :9#{p^:o
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Fxx2vTV4ag
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /+O8A}
FROM sysfiles 15DK\_;
WHERE name = @LogicalFileName 1R9?[RE
DROP TABLE DummyTrans w{x(YVSH
SET NOCOUNT OFF Nj&%xe>].
8、说明:更改某个表 ^|(4j_.(e
exec sp_changeobjectowner 'tablename','dbo' pY#EXZ#
9、存储更改全部表 ;XQ lj?:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch X>8?p'*
@OldOwner as NVARCHAR(128), Q9tE^d+%
@NewOwner as NVARCHAR(128) qFbUM;
AS )0MshgM
DECLARE @Name as NVARCHAR(128) w1(06A}/
DECLARE @Owner as NVARCHAR(128) v};qMceJ
DECLARE @OwnerName as NVARCHAR(128) X$Vz
DECLARE curObject CURSOR FOR $50"3g!Y
select 'Name' = name, _5 tqO5'
'Owner' = user_name(uid) z}2e;d 7
from sysobjects m@yVG|eP#
where user_name(uid)=@OldOwner _k.bGYldk
order by name Jd"s~n<>K
OPEN curObject N4|q2Jvj6
FETCH NEXT FROM curObject INTO @Name, @Owner lNVAKwW2#
WHILE(@@FETCH_STATUS=0) )Hm[j)YI
BEGIN Er1u1@
if @Owner=@OldOwner NVWeJ+w
begin ~(OIo7#;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) rGGepd
exec sp_changeobjectowner @OwnerName, @NewOwner HKN"$(Q
end A=]F_
-- select @name,@NewOwner,@OldOwner 810<1NP
FETCH NEXT FROM curObject INTO @Name, @Owner 4@iJ|l
END kS#DKo
close curObject cGzYW~K
deallocate curObject nYt\e]3
GO H-KwkH`L4
10、SQL SERVER中直接循环写入数据 _D,f4.R
declare @i int mX.3R+t
set @i=1 VD3MJ 8!w
while @i<30 %7d@+
.
begin 3b\8907
insert into test (userid) values(@i) G_N-}J>EP
set @i=@i+1 1za'u_
end ~.9o{?pbG
小记存储过程中经常用到的本周,本月,本年函数 HmB[oH"x
Dateadd(wk,datediff(wk,0,getdate()),-1) B~g05`s
Dateadd(wk,datediff(wk,0,getdate()),6) |$?Ux,(6
Dateadd(mm,datediff(mm,0,getdate()),0) O| 6\g>ew
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 05VOUa*pb
Dateadd(yy,datediff(yy,0,getdate()),0) 7e{X$'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Q>a7Ps@~
上面的SQL代码只是一个时间段 /,N!g_"Z
Dateadd(wk,datediff(wk,0,getdate()),-1) {F+M&+``
Dateadd(wk,datediff(wk,0,getdate()),6) s?x>Yl
%
就是表示本周时间段. Dq%r
! )
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^!p<zZ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +[8Kl=]L
而在存储过程中 ]{2{:`s
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Q] yT
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0ij~e<