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。 2q
NA\-0i>
aw923wEi
~n"?*I`
一、基础 :`>$B?x+
1、说明:创建数据库 k-Z:z?M
CREATE DATABASE database-name f7SMO-3a
2、说明:删除数据库 e7Sp?>-d
drop database dbname "5!T-Z+F
3、说明:备份sql server \{a!Z&df
--- 创建 备份数据的 device 6!`GUU
USE master n)Z u>
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :R-_EY$k6
--- 开始 备份 Q}: $F{
BACKUP DATABASE pubs TO testBack {>3J 96
4、说明:创建新表 :cxA
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) EY`]""~8v
根据已有的表创建新表: $ {h1(ec8
A:create table tab_new like tab_old (使用旧表创建新表) M
ZAz= )-
B:create table tab_new as select col1,col2... from tab_old definition only S}b^_+UbP
5、说明:删除新表
hm\UqIt
drop table tabname kaT
!
6、说明:增加一个列 N>H#Ew@2U
Alter table tabname add column col type (KLhF
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。 EzeU-!|W
7、说明:添加主键: Alter table tabname add primary key(col) :I{9k~
说明:删除主键: Alter table tabname drop primary key(col) Ygbyia|
8、说明:创建索引:create [unique] index idxname on tabname(col....) [[#R ry
删除索引:drop index idxname B1V+CP3t
注:索引是不可更改的,想更改必须删除重新建。 w:pPd;nz0Y
9、说明:创建视图:create view viewname as select statement 6U0BP
删除视图:drop view viewname A+MG?k>yg
10、说明:几个简单的基本的sql语句 WM;5/;bB
选择:select * from table1 where 范围 ]6
HR
插入:insert into table1(field1,field2) values(value1,value2) fm^J-
删除:delete from table1 where 范围 B'e@RhU;
更新:update table1 set field1=value1 where 范围 VaW^;d#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %a?\y_a=b
排序:select * from table1 order by field1,field2 [desc] n)j0h-
总数:select count as totalcount from table1 I
6'!b/
求和:select sum(field1) as sumvalue from table1 p/qu4[Mm
平均:select avg(field1) as avgvalue from table1 P6I<M}p
最大:select max(field1) as maxvalue from table1 4?fpk9c{2
最小:select min(field1) as minvalue from table1 O I0N(V
'T|EwrS j
!Ln 'Mi_B
hD[r6c
11、说明:几个高级查询运算词 AHo }K\O?r
M>Q3;s
vGnFX0?h
A: UNION 运算符 g%V#Z`*|
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。 ["#H/L]3
B: EXCEPT 运算符 ~"\WV4}`v
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。 #~m8zG
C: INTERSECT 运算符 |)C
#
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。 H_JE)a:+
注:使用运算词的几个查询结果行必须是一致的。 gBO,
12、说明:使用外连接 ckb(+*+l
A、left outer join: &ty-aB=F
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。 &Hyy .a
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 qj/Zk[
B:right outer join: WH"'Ju5}
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。 \:g\?[
C:full outer join: 0CvGpM,
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。 B]NcY&A
9q+W>wt
n2~WUK
二、提升 rvU^W+d
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 2rW9ja
法一:select * into b from a where 1<>1 w59q* 2
法二:select top 0 * into b from a m] yUcj{F
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .^2.h
insert into b(a, b, c) select d,e,f from b; U)M&AYb
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) *fs[]q'Q
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 TNckyP75u
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. XDAP[V
4、说明:子查询(表名1:a 表名2:b) E+ |K3EJ
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) DgK*>A
5、说明:显示文章、提交人和最后回复时间 m[%':^vSr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?6\N&MTF
6、说明:外连接查询(表名1:a 表名2:b) mK/E1a)AG3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?lfyC/
7、说明:在线视图查询(表名1:a )
iDx(qdla
select * from (SELECT a,b,c FROM a) T where t.a > 1; q{_ f"
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 C4qK52'2s
select * from table1 where time between time1 and time2 spTz}p^\O
select a,b,c, from table1 where a not between 数值1 and 数值2 +'Y?K]zbt
9、说明:in 的使用方法 5JEOLPS
select * from table1 where a [not] in ('值1','值2','值4','值6') 5rf Dm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 J[0 5T1
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -L4G)%L\
11、说明:四表联查问题: HI{h>g T
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 ..... LEOri=?RF
12、说明:日程安排提前五分钟提醒 T*gG <8
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $P#x>#+[A
13、说明:一条sql 语句搞定数据库分页 /E2P
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Sa%%3_&
14、说明:前10条记录 # S/n3
select top 10 * form table1 where 范围 _!VtM#G[
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ~-[!>1!%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5Po:$(
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 +$#<gp"
(select a from tableA ) except (select a from tableB) except (select a from tableC) Q"D5D
rj
17、说明:随机取出10条数据 '&hd^9]Lo
select top 10 * from tablename order by newid() d"IZt;s/,
18、说明:随机选择记录 Phk3Jv
select newid() 2 S~( P
19、说明:删除重复记录 2@lGY_O!m
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !*L)v
20、说明:列出数据库里所有的表名 $U.|
select name from sysobjects where type='U' w;{Q)_A
21、说明:列出表里的所有的 OF={k[
select name from syscolumns where id=object_id('TableName') M 87CP=yc
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。 ?hGE[.(eh]
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 =PQ4S2Q
显示结果: 3[y$$qXI
type vender pcs jl>TZ)4}V
电脑 A 1 Qu,R6G
电脑 A 1 +lfO4^V
光盘 B 2 [|YvVA
光盘 A 2 1x=x,lcL
手机 B 3 ]{#=WTp]
手机 C 3 zwU[!i)
23、说明:初始化表table1 c_S~{a44Ud
TRUNCATE TABLE table1 +p63J
24、说明:选择从10到15的记录 [U",yN]d
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7M4J{}9
Su7N ?X!
>qOG^{&x
Axns
三、技巧 S<NK!89
1、1=1,1=2的使用,在SQL语句组合时用的较多 M_Ag*?2I
"where 1=1" 是表示选择全部 "where 1=2"全部不选, d{Jk:@.1
如: 1++g@8
if @strWhere !='' vG'#5%,|
begin 8Th,C{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere O1c:X7lHc
end HV)aVkr/&
else &z1U0uk
begin pZlsDM/=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $A9Pi"/*z
end O=V_7I5
我们可以直接写成 RqGX(Iuv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere aVHIU3
2、收缩数据库 ^~-YS-.J#,
--重建索引 _~;%zFX
DBCC REINDEX vm[*+&\2
DBCC INDEXDEFRAG 7@>/O)>(AS
--收缩数据和日志 ]b;m~|9
DBCC SHRINKDB &K60n6q{aQ
DBCC SHRINKFILE _qf39fM;\
3、压缩数据库 /q\e&&e
dbcc shrinkdatabase(dbname) ~a[/l
4、转移数据库给新用户以已存在用户权限 bA,Zfsr6#
exec sp_change_users_login 'update_one','newname','oldname' mi<Q3;m
go O+|C<;K
5、检查备份集 n<j+KD#a
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6
h#U,G
6、修复数据库 po*8WSl9c[
ALTER DATABASE [dvbbs] SET SINGLE_USER ws5Ue4g|
GO z9[TjTH^}T
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WYTqQqQk
GO <fG\J
ALTER DATABASE [dvbbs] SET MULTI_USER ;10YG6:
GO qjhV/fsfb
7、日志清除 =xIZJ8e
SET NOCOUNT ON jw=PeT|
DECLARE @LogicalFileName sysname, p__wBUB
@MaxMinutes INT, $Y6\m`
@NewSize INT $Q8
&TM}E
USE tablename -- 要操作的数据库名 5[SwF&zZ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 SDil\x
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ebI2gEu;a
@NewSize = 1 -- 你想设定的日志文件的大小(M) >*h+N?
m
-- Setup / initialize `8W HVC$
DECLARE @OriginalSize int O1\Hx8^
SELECT @OriginalSize = size [z2UfHpt~
FROM sysfiles _C?Wk:Y@
WHERE name = @LogicalFileName i cTpx#|=
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MXcW
&b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x+Xd7N1
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' aqI"4v]~b
FROM sysfiles uB.kkkGZ M
WHERE name = @LogicalFileName k*fU:q1
CREATE TABLE DummyTrans !`I@Rk]`c
(DummyColumn char (8000) not null) `e
=IXkt
DECLARE @Counter INT, B ??07j
@StartTime DATETIME, j8&NscK)
@TruncLog VARCHAR(255) $N)G:=M!s
SELECT @StartTime = GETDATE(), zVw5 (Tc
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \OVtvJV]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) `R8&(kQ
EXEC (@TruncLog) d6QrB"J`
-- Wrap the log if necessary. 9m$;C'}Z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <Pt?N2]A|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Z)W8Of_
AND (@OriginalSize * 8 /1024) > @NewSize )ciP6WzzbI
BEGIN -- Outer loop. vlbZ5
SELECT @Counter = 0 Vz/w.%_g
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _=s9o/Cn]
BEGIN -- update -Y/i
h(I^
INSERT DummyTrans VALUES ('Fill Log') O+=%Mz(l
DELETE DummyTrans 4kM/`g6?,q
SELECT @Counter = @Counter + 1 !B%em%Tv
END 2r!ltG3}
EXEC (@TruncLog) Om0$6O
END zW%Em81Wd
SELECT 'Final Size of ' + db_name() + ' LOG is ' + %DKFF4k
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Yn}Gj'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Re8x!e'>
FROM sysfiles !Rl|o^Vw>{
WHERE name = @LogicalFileName D:/ n2_
DROP TABLE DummyTrans gfg,V.:
SET NOCOUNT OFF fx_#3=bXi
8、说明:更改某个表 ,\\ba_*z
exec sp_changeobjectowner 'tablename','dbo' ~Xxmj!nOf
9、存储更改全部表 #%p44%W
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch c,2& -T}
@OldOwner as NVARCHAR(128), Lkm-<
@NewOwner as NVARCHAR(128) tf~B,?
AS w_56y8Pd4
DECLARE @Name as NVARCHAR(128) Kt_oo[ey{
DECLARE @Owner as NVARCHAR(128) +r8bGS]ki
DECLARE @OwnerName as NVARCHAR(128) &*<27-x
DECLARE curObject CURSOR FOR A ]A{HEX
select 'Name' = name, ^r\rpSN
'Owner' = user_name(uid) I1E9E$m5\<
from sysobjects .Az36wD
where user_name(uid)=@OldOwner a'i
Q("
order by name lln"c
OPEN curObject I$xZV?d.
FETCH NEXT FROM curObject INTO @Name, @Owner njy2pDC@
WHILE(@@FETCH_STATUS=0) :jl*Y-mM
BEGIN C:J;'[,S
if @Owner=@OldOwner fkzSX8a9}
begin 2H|:/y
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /e '3\,2_
exec sp_changeobjectowner @OwnerName, @NewOwner LW]fme<V?
end =*,SD
-- select @name,@NewOwner,@OldOwner K?^;|m-
FETCH NEXT FROM curObject INTO @Name, @Owner 'K,\
END t_3j_`
close curObject {q0+PzgP
deallocate curObject m;OvOc,
GO -&8( MT*
10、SQL SERVER中直接循环写入数据 &R72$H9C8i
declare @i int S:_Ms{S
set @i=1 YO7U}6wBt
while @i<30 EJkHPn
begin QO'Hyf t
insert into test (userid) values(@i) :X;G]B
.
set @i=@i+1 Kq")\Ha,f
end X(N~tE
小记存储过程中经常用到的本周,本月,本年函数 EMmgX*iu@
Dateadd(wk,datediff(wk,0,getdate()),-1) p'/\eBhG]=
Dateadd(wk,datediff(wk,0,getdate()),6) At(88(y-W
Dateadd(mm,datediff(mm,0,getdate()),0) )5Khl"6!z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) K&L!O3#(
Dateadd(yy,datediff(yy,0,getdate()),0) bBjr hi
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) h:%,>I%{
上面的SQL代码只是一个时间段 y7,fFUKl
Dateadd(wk,datediff(wk,0,getdate()),-1) p&<Ssc
Dateadd(wk,datediff(wk,0,getdate()),6) Js,! G
就是表示本周时间段. p27Dcwov
下面的SQL的条件部分,就是查询时间段在本周范围内的: )O1]|r7v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) i1
E|lp)
而在存储过程中 *'/,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) P>7Xbm,VP
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) x>#{C,Fi