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。 ]c\`EHN
>y}> 5kv
a@_n>$LZL
一、基础 bTx4}>=5l
1、说明:创建数据库 A\"4[PXpQ
CREATE DATABASE database-name XYV`[,^h&
2、说明:删除数据库 $v8T%'p+
drop database dbname 3]NKAPY
3、说明:备份sql server "<L9-vb
--- 创建 备份数据的 device pNHL &H\
USE master u3 X!O
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' '*U_!RmQ
--- 开始 备份 _0&U'/cs
BACKUP DATABASE pubs TO testBack SbtZhg=S_
4、说明:创建新表 Qc Xw -
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) G{+zKs}~
根据已有的表创建新表: gYpFF=7j<@
A:create table tab_new like tab_old (使用旧表创建新表) n>o=RQ2
B:create table tab_new as select col1,col2... from tab_old definition only _Fkb$NJ"]Q
5、说明:删除新表 us#ji i.<
drop table tabname |o_
N$70
6、说明:增加一个列 -Lsl
Alter table tabname add column col type 3D,tnn+J
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 YEiw!
7、说明:添加主键: Alter table tabname add primary key(col) 7&dF=/:X@
说明:删除主键: Alter table tabname drop primary key(col) YyY?<<z%
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3cH^
,F
删除索引:drop index idxname 5uM`4xkj
注:索引是不可更改的,想更改必须删除重新建。 uE#"wm'J
9、说明:创建视图:create view viewname as select statement 0LWV.OIIC
删除视图:drop view viewname PywUPsJ
10、说明:几个简单的基本的sql语句 [7{cf`C
选择:select * from table1 where 范围 !4"$O@U4
插入:insert into table1(field1,field2) values(value1,value2) efyGjfoO
删除:delete from table1 where 范围 V' sq'XB
更新:update table1 set field1=value1 where 范围 M\08 7k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! SR4 mbQ:
排序:select * from table1 order by field1,field2 [desc] j3o?B
总数:select count as totalcount from table1 _bCIVf`
求和:select sum(field1) as sumvalue from table1 ) C#>@W
平均:select avg(field1) as avgvalue from table1 UJ)(Sw
最大:select max(field1) as maxvalue from table1 OQ3IkE`G
最小:select min(field1) as minvalue from table1 b\SB
o^d
I_`$$-|
2N&S__
11、说明:几个高级查询运算词 q' t"
@Bsvk9}
9 b&HqkXX
A: UNION 运算符 PmUq~YZ7
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。 e=i9l
B: EXCEPT 运算符 dY?>:ce
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。 1mv8[^pF
C: INTERSECT 运算符 /p{$HkVw
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 \NL*$SnxP
注:使用运算词的几个查询结果行必须是一致的。 q] '2'"k
12、说明:使用外连接 !imjfkG
A、left outer join: ?KFj=Yo
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。 |v"&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 U uSCqI};
B:right outer join: {UuSNZ[^
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。 w!l*!G
C:full outer join: 7]
>z e
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。 K!tM "`a
5BM rn0
D'
h%.
二、提升 ](k}B*Abh
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) kI~;'M
法一:select * into b from a where 1<>1 kznm$2 b
法二:select top 0 * into b from a mN"g~o*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o|1_I?_
insert into b(a, b, c) select d,e,f from b; nsXyReWka
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) wEix 8Ow*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P7qzZ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. XTq+ 9
4、说明:子查询(表名1:a 表名2:b) Yx"~_xA/u
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) J'yiVneMw
5、说明:显示文章、提交人和最后回复时间 4='/]z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ^B'N\[
6、说明:外连接查询(表名1:a 表名2:b) $btk48a 7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c P\2x9T
7、说明:在线视图查询(表名1:a ) N}\3UHtO
select * from (SELECT a,b,c FROM a) T where t.a > 1; $*+`;PG-
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 ?fvK<0S`
select * from table1 where time between time1 and time2 810uxw{\
select a,b,c, from table1 where a not between 数值1 and 数值2 &bwI7cO
9、说明:in 的使用方法 eq4Yc*|9
select * from table1 where a [not] in ('值1','值2','值4','值6') ghaO#kI
10、说明:两张关联表,删除主表中已经在副表中没有的信息 6M6r&,yRu
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \x~},!l
11、说明:四表联查问题: )VkH':yCM
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 ..... bSk)GZyH\d
12、说明:日程安排提前五分钟提醒 MgQb" qx
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $$---Y
13、说明:一条sql 语句搞定数据库分页 :w26d-QR(
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 3W@ta1
14、说明:前10条记录 ;TCT%j`^o
select top 10 * form table1 where 范围 3\?yjL^
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.) 6;}W)S
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0?,%B?A8O
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 =R||c
(select a from tableA ) except (select a from tableB) except (select a from tableC) }b]z+4Ua(
17、说明:随机取出10条数据 X8
select top 10 * from tablename order by newid() xY`$j'u
18、说明:随机选择记录 0'II6,:
select newid() \r&9PkHWo
19、说明:删除重复记录 Ehg(xK
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) i/q1>
20、说明:列出数据库里所有的表名 R?J=5tO
select name from sysobjects where type='U' `>\>'V<&
21、说明:列出表里的所有的 -Z&9pI(3R~
select name from syscolumns where id=object_id('TableName') F'JceU
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。 a*{ -r]
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 XjJ[7"hs*
显示结果: z5IdYF?
type vender pcs c~n:xblv
电脑 A 1 <):= mr7
电脑 A 1 cy( WD#^
光盘 B 2 Y~-P9
光盘 A 2 ck#MpQ!An
手机 B 3 ),4cb
手机 C 3 %gV~e@|
23、说明:初始化表table1 !^(?C@TQ
TRUNCATE TABLE table1 S0p[Kt
24、说明:选择从10到15的记录 /\UFJ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ; +R
7Ezy-x2h
,&rHBNS
rL<a^/b/=
三、技巧
bjB4
1、1=1,1=2的使用,在SQL语句组合时用的较多 6e:#x:O
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 76RFu@k
如: {*t0WE&1t
if @strWhere !='' Huho|6ohH
begin 629#t`W\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere K|sx"u|?
end sB%QqFRP
else hd_<J]C
begin FKk.BA957h
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' nY 50dFA,
end "/$2oYNy+
我们可以直接写成 l5CFm8%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere x10u?@
2、收缩数据库 "'*w_H0
--重建索引 Ggp. %kS6F
DBCC REINDEX q;=! =aRg
DBCC INDEXDEFRAG ]Qh0+!SdG
--收缩数据和日志 NmZowh$M
DBCC SHRINKDB NVq3h\[X
DBCC SHRINKFILE v0'`K 5M
3、压缩数据库 "/qm,$
dbcc shrinkdatabase(dbname) I2<5#|CXpZ
4、转移数据库给新用户以已存在用户权限 >sm<$'vZ/
exec sp_change_users_login 'update_one','newname','oldname' ;TTH
go #^eXnhj 9
5、检查备份集 2H2Yxe7? -
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' PNhxF C.
6、修复数据库 [vyi_0[
ALTER DATABASE [dvbbs] SET SINGLE_USER _/@u[dWeL
GO KBy*QA
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK SH/^qDT'
GO YuKg|<WO
ALTER DATABASE [dvbbs] SET MULTI_USER =p7eP
GO ,K~r':ht
7、日志清除 S_dM{.!Z(,
SET NOCOUNT ON M5T4{^i
DECLARE @LogicalFileName sysname, Mib<1ZM
@MaxMinutes INT, {~+o+LV
@NewSize INT C`r{B.t`GT
USE tablename -- 要操作的数据库名 K%RjWX=H
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 NX9K%J
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *_CzCl^
@NewSize = 1 -- 你想设定的日志文件的大小(M) xJ|_R,>.H
-- Setup / initialize Hw
1cc3!
DECLARE @OriginalSize int We?cRb
SELECT @OriginalSize = size g]E>e v{`
FROM sysfiles CH+mzy
WHERE name = @LogicalFileName GLE"[!s]f
SELECT 'Original Size of ' + db_name() + ' LOG is ' + iFkXt<_A
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + k*uLjU
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6Dz N.fz
FROM sysfiles )HJ#|JpxC
WHERE name = @LogicalFileName u5E\wRn
CREATE TABLE DummyTrans t @vb3
(DummyColumn char (8000) not null) Xjs`iK=w
DECLARE @Counter INT, #f-pkeaeq
@StartTime DATETIME, r`5svY
@TruncLog VARCHAR(255) I*hzlE
SELECT @StartTime = GETDATE(), r%UsUj
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' IT=<p60"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) mVNHH!
EXEC (@TruncLog) ~"}o^#@DwJ
-- Wrap the log if necessary. Z,}c)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired = &"x6F.`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [
F7ru4"{
AND (@OriginalSize * 8 /1024) > @NewSize Dwuao`~Xm
BEGIN -- Outer loop. o*
C_9M
SELECT @Counter = 0 .LA?2N
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) zyPc<\HoK
BEGIN -- update $fFh4O4
INSERT DummyTrans VALUES ('Fill Log') gjDxgNpa
DELETE DummyTrans 8qWN~Gk1p{
SELECT @Counter = @Counter + 1 AOscewQ
END ((cRe6
EXEC (@TruncLog) G7uYkJO
END bTbF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + UNJAfr P
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1Zt>andBF
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' G e+T[
FROM sysfiles ?`T-A\A=
WHERE name = @LogicalFileName ^g
N/ 5
DROP TABLE DummyTrans ViYfK7Z
SET NOCOUNT OFF Td,s"p>Vq
8、说明:更改某个表 iWp
6^g
exec sp_changeobjectowner 'tablename','dbo' S\R5SRE
9、存储更改全部表 +
[~)a4#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch KuJNKuHa.
@OldOwner as NVARCHAR(128), :jr`}Z%;y
@NewOwner as NVARCHAR(128) +Hkr\
AS 5Vj O:>
DECLARE @Name as NVARCHAR(128) $~)YI/b
DECLARE @Owner as NVARCHAR(128) W@FSQ8b>$m
DECLARE @OwnerName as NVARCHAR(128) 0AD8X+M{P
DECLARE curObject CURSOR FOR ,jq:%Y[KZ
select 'Name' = name, :b`ywSp`
'Owner' = user_name(uid) P87Lo4Rd
from sysobjects Q.} guI\
where user_name(uid)=@OldOwner fprP$MbI
order by name ae0t*;~
OPEN curObject (d>}Fp
FETCH NEXT FROM curObject INTO @Name, @Owner DVz_;m6)
WHILE(@@FETCH_STATUS=0) p-XO4Pc6
BEGIN L25%KGg'o
if @Owner=@OldOwner )18C(V-x
begin ToX--w4
set @OwnerName = @OldOwner + '.' + rtrim(@Name) yZQcxg%
exec sp_changeobjectowner @OwnerName, @NewOwner PWk\#dJN&
end &M{;[O{
-- select @name,@NewOwner,@OldOwner L%;[tu(*
FETCH NEXT FROM curObject INTO @Name, @Owner ;LqpX!Pi
f
END mnL+@mm
close curObject nZ %%{#T7
deallocate curObject 5jAS1XG
GO %00cC~}4
10、SQL SERVER中直接循环写入数据 (z 9M
declare @i int )f,9 h
set @i=1 m^gxEPJK
while @i<30 #7['M;_
begin `!Yd$=*c_&
insert into test (userid) values(@i) =z[$o9
set @i=@i+1 %U6A"?To
end DIw9ov>k
小记存储过程中经常用到的本周,本月,本年函数 y}1Pc*
Dateadd(wk,datediff(wk,0,getdate()),-1) *-(8Z>9
Dateadd(wk,datediff(wk,0,getdate()),6) 6{!Cx9V
Dateadd(mm,datediff(mm,0,getdate()),0) DM,)nh6'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kgh0
Dateadd(yy,datediff(yy,0,getdate()),0) eY[kUMo
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) @Yn+ir0>O
上面的SQL代码只是一个时间段 V5' (op /
Dateadd(wk,datediff(wk,0,getdate()),-1) mgMa)yc!dp
Dateadd(wk,datediff(wk,0,getdate()),6) '<{Jlz(u9
就是表示本周时间段. gY!?JZC-0
下面的SQL的条件部分,就是查询时间段在本周范围内的:
JKV&c=I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) `BVXF#sb
而在存储过程中 K[yP{01
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "!ks7:}v
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) foUB/&Ee