1、SQL 语句收集精妙 SQL 语句收集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。一、基础1、说明:创建数据库CREATE DATABASE database-name2、说明:删除数据库drop database dbname3、说明:备份sql server- 创建 备份数据的 deviceUSE masterEXEC sp_addumpdevice disk, testBack, c:mssql7backupMyNwind_1.dat- 开始 备份BACKUP DATABASE pubs TO testBack4、说明:创建新表create tab
2、le tabname(col1 type1 not null primary key,col2 type2 not null,.)根据已有的表创建新表:A:create table tab_new like tab_old (使用旧表创建新表)B:create table tab_new as select col1,col2. from tab_old definition only5、说明:删除新表drop table tabname6、说明:增加一个列Alter table tabname add column col type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,
3、唯一能改变的是增加varchar类型的长度。7、说明:添加主键: Alter table tabname add primary key(col)说明:删除主键: Alter table tabname drop primary key(col)8、说明:创建索引:create unique index idxname on tabname(col.)删除索引:drop index idxname注:索引是不可更改的,想更改必须删除重新建。9、说明:创建视图:create view viewname as select statement删除视图:drop view viewname10、基本
4、的sql语句选择:select * from table1 where 范围插入:insert into table1(field1,field2) values(value1,value2)删除:delete from table1 where 范围更新:update table1 set field1=value1 where 范围查找:select * from table1 where field1 like %value1% -like的语法很精妙,查资料!排序:select * from table1 order by field1,field2 desc总数:select cou
5、nt as totalcount from table1求和:select sum(field1) as sumvalue from table1平均:select avg(field1) as avgvalue from table1最大:select max(field1) as maxvalue from table1最小:select min(field1) as minvalue from table111、说明:几个高级查询运算词A: UNION 运算符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
6、 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。B: EXCEPT 运算符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。C: INTERSECT 运算符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
7、除重复行。注:使用运算词的几个查询结果行必须是一致的。12、说明:使用外连接A、left outer join: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。SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.cB:right outer join: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。C:full outer join: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。13、按时间查询数据 select * fro
8、m tablename t where t.tdate=to_date(2011-08-17, yyyy-mm-dd) -查某一天的 select * from tablename t where to_char(t.tdate,yyyy-mm-dd)2011-08-17 一段时间内的 select * from tablename c where to_char(c.begin_date,yyyy-mm-dd hh24:mi:ss)2011-03-15 13:44:55 and c.begin_dateto_date(2011-03-25 13:44:55, yyyy-mm-dd hh24:
9、mi:ss)14、查询数据库版本select * from v$version;-(oracle)15、查询数据表大小select sum(bytes)/(1024*1024)as m from user_segments where segment_name=BO_DEMA_COLL -(oracle)16、查询数据库日志(oracle)select * from v$sqlselect * from v$sqlareselect * from bo_sys_log二、提升1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)法一:select * into b fro
10、m a where 11法二:select top 0 * into b from a法三: create table newtable as select * from oldtable where 11(plsql)2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)insert into b(a, b, c) select d,e,f from b;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)insert into b(a, b, c) select d,e,f from b in 具体数据库 where 条件例子:.from b
11、in &Server.MapPath(.)&data.mdb & where.4、说明:子查询(表名1:a 表名2:b)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)5、说明:显示文章、提交人和最后回复时间select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b6、说明:外连接查询(
12、表名1:a 表名2:b)select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c7、说明:在线视图查询(表名1:a )select * from (SELECT a,b,c FROM a) T where t.a 1;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select * from table1 where time between time1 and time2select a,b,c, from table1 where a not be
13、tween 数值1 and 数值29、说明:in 的使用方法select * from table1 where a not in (值1,值2,值4,值6)10、说明:两张关联表,删除主表中已经在副表中没有的信息delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )11、说明:四表联查问题:select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join
14、d on a.a=d.d where .12、说明:日程安排提前五分钟提醒SQL: select * from 日程安排 where datediff(minute,f开始时间,getdate()513、说明:一条sql 语句搞定数据库分页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 (Sql servert)14、说明:前10条记录select top 10 * form table1 where
15、范围 (Sql servert)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15、(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.)select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)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(select a from tableA ) except (select a from tableB) except
16、 (select a from tableC)17、说明:随机取出10条数据select top 10 * from tablename order by newid()18、说明:随机选择记录select newid()19、说明:删除重复记录 Delete from tablename where id not in (select max(id) from tablename group by col1,col2,.) -需要保证ID不重复的delete from sm_temp b where rowid not in(select max(rowid) from sm_temp gr
17、oup by id) -plsql适用,rowid为数据库本身定义的ID,是肯定不重复的。20、说明:列出数据库里所有的表名select name from sysobjects where type=Uselect * from user_tables where table_name like SP% or table_name likeWM%21、说明:列出表里的所有的select name from syscolumns where id=object_id(TableName)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
18、select 中的case。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显示结果:type vender pcs电脑 A 1电脑 A 1光盘 B 2光盘 A 2手机 B 3手机 C 323、说明:初始化表table1TRUNCATE TABLE table1(慎用,初始化了就没得恢复了,不确定的最好
19、用delete)24、说明:选择从10到15的记录select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc25、查找字段值重复的数据select b.a, b.字段 from (select count(字段) as a, 字段 from 表名 group by 字段) b where b.a 126、汉字按拼音首字母排序Select * From tablename t order bynlssort(t.cloumn,NLS_SORT=SCHINESE_PINYIN_
20、M);27、代码转换为文字select case when status = 0 then 有效 when status = 1 then 无效 else 其他 end as statu from tablename28、将一个字段中以逗号分隔的数据生成一个表with test as (select remarks c from bo_sys_para where para = FAUL_ROLE_TYPE and value=2) select substr(t.ca, instr(t.ca, , 1, c.lv) + 1, instr(t.ca, , 1, c.lv + 1) - (ins
21、tr(t.ca, , 1, c.lv) + 1) AS c from (select , | c | , AS ca, length(c | ,) - nvl(length(REPLACE(c, ,), 0) AS cnt FROM test) t, (select LEVEL lv from dual CONNECT BY LEVEL = 100) c where c.lv DATEDIFF (mi, StartTime, GETDATE() - time has not expired AND OriginalSize = (SELECT size FROM sysfiles WHERE
22、name = LogicalFileName) AND (OriginalSize * 8 /1024) NewSize BEGIN - Outer loop. SELECT Counter = 0 WHILE (Counter OriginalSize / 16) AND (Counter 50000) BEGIN - update INSERT DummyTrans VALUES (Fill Log) DELETE DummyTrans SELECT Counter = Counter + 1 END EXEC (TruncLog) END SELECT Final Size of + d
23、b_name() + LOG is + CONVERT(VARCHAR(30),size) + 8K pages or + CONVERT(VARCHAR(30),(size*8/1024) + MB FROM sysfiles WHERE name = LogicalFileNameDROP TABLE DummyTransSET NOCOUNT OFF8、说明:更改某个表exec sp_changeobjectowner tablename,dbo9、存储更改全部表CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch OldOwner as NV
24、ARCHAR(128), NewOwner as NVARCHAR(128)ASDECLARE Name as NVARCHAR(128)DECLARE Owner as NVARCHAR(128)DECLARE OwnerName as NVARCHAR(128)DECLARE curObject CURSOR FOR select Name = name, Owner = user_name(uid) from sysobjects where user_name(uid)=OldOwner order by nameOPEN curObjectFETCH NEXT FROM curObj
25、ect INTO Name, OwnerWHILE(FETCH_STATUS=0)BEGIN if Owner=OldOwner begin set OwnerName = OldOwner + . + rtrim(Name) exec sp_changeobjectowner OwnerName, NewOwner end- select name,NewOwner,OldOwner FETCH NEXT FROM curObject INTO Name, OwnerENDclose curObjectdeallocate curObjectGO10、SQL SERVER中直接循环写入数据declare i intset i=1while i30begin ins