Oracle数据常用操作

将用逗号隔开字段拆分成两行：

select * from mp_fs_file_info a,dm_process_upload b where instr(b.attachment,a.file_id,1,1)>0;

字段名小写加双引号
to_char转换成制定格式。
select to_char(xmmc), 项目名称，dwmc "name" from desulfidation，

插入多条数据：
insert into imdt_role_permission (
     (select 3,5 from dual)
     union
     (select 3,23 from dual)
     union
     (select 3,30 from dual)
     union
     (select 3,31 from dual)
     )
)

delete from calm_role_permission where role_id=2 and permission_id between 1 and 12

查询列表最大数据记录方法：

<wiz_code_mirror>

 
select a.* from pc_evaluation_upload a where not exists(

select 1 from pc_evaluation_upload b where b.well_id=a.well_id and b.create_date >a.create_date) and  a.well_id ='0000000039';//两个字段不出现重复,时间相同时需要用distinct

​

​

select a.* from pc_evaluation_upload a inner join

 (select well_id,max(create_date) maxgdtime from pc_evaluation_upload group by well_id) b 

 on a.well_id=b.well_id and a.create_date=b.maxgdtime

你可以理解为 JOIN 　　是 INNER JOIN 的缩写。

LEFT JOIN 等价于 LEFT OUTER JOIN

RIGHT JOIN 等价于 RIGHT OUTER JOIN，等价于from t1,t1 where t1.id =t2.id

having：

group by以后的where过滤。

查询字段出现两次以上的数据，也可用于在另一张表中

SELECT * FROM material_plan_ming a WHERE a.material_plan_id IN (

SELECT b.material_plan_id FROM material_plan_ming b

GROUP BY b.material_plan_id HAVING COUNT(b.material_plan_id)>1);

distinct和group by去重区别：

即只有所有指定的列信息都相同，才会被认为是重复的信息。

单纯的去重操作使用distinct，速度是快于group by的。

group by使用的频率相对较高，但正如其功能一样，它的目的是用来进行聚合统计的，虽然也可能实现去重的功能，但这并不是它的长项

group by 的优势是可以包含一个聚合函数，最大值，max，min，sum等。

不包含聚集函数的GROUP BY操作来说，和DISTINCT操作是等价的

SELECT DISTINCT a.key_id a.well_id,a.barrier_type_id FROM pc_evaluate_wellhead a WHERE a.well_id='0000000206'

select e.well_id,e.barrier_type_id from pc_evaluate_wellhead e group by e.well_id,e.barrier_type_id

SELECT DISTINCT well_id FROM pc_evaluate_wellhead;

SELECT well_id, COUNT(well_id) from pc_evaluate_wellhead group BY well_id;

行转列,group分组查询，逗号隔开：

select con_basis_id, sum(con_amount) from contract_basis_pro group by con_basis_id;

select LISTAGG(to_char(pro_name),',') WITHIN GROUP( ORDER BY con_basis_id) pro_name,con_basis_id from contract_basis_pro group by con_basis_id;

select con_basis_id,to_char(wm_concat(pro_name)) pro_name,to_char(wm_concat(con_amount)) con_amount,to_char(wm_concat(remark)) remark

from contract_basis_pro group by con_basis_id ;

select con_basis_id,wm_concat(to_char(pro_name)) pro_name,wm_concat(to_char(con_amount)) con_amount,wm_concat(to_char(remark)) remark from contract_basis_pro group by con_basis_id ;

wm_concat(toto)over(partition by ename order by type)

行转列排序问题：

SELECT con_basis_id, max(pro_id) pro_id FROM(SELECT con_basis_id,

to_char(wm_concat(to_char(pro_id)) over (partition by con_basis_id order by ID)) pro_id

FROM contract_basis_pro ) GROUP BY con_basis_id

列转行：

select REGEXP_SUBSTR(a.file_url ,'[^,]+',1,l) as file_url

from reply_file a,

(SELECT LEVEL l FROM DUAL CONNECT BY LEVEL<=100) b

WHERE l <=LENGTH(a.file_url) - LENGTH(REPLACE(file_url,','))+1;

查询有重复的语句：（having 对group后的组进行过滤，筛选。某些条件可用where替换）

select * from pro_bas_info where pro_code in (select pro_code from pro_bas_info group by pro_code having COUNT(*)>1);

select well_id, max(create_date) maxgdtime from pc_evaluation_upload group by well_id HAVING count(*) > 2

分页查询：(第二种方式效率较高）

SELECT a.*, ROWNUM RN FROM (SELECT * FROM mp_fs_file_info ORDER BY R_CREATEDATE DESC) a

WHERE ROWNUM BETWEEN 0 AND 4;

SELECT * FROM (

SELECT a.*, ROWNUM RN FROM (SELECT * FROM mp_fs_file_info ORDER BY R_CREATEDATE DESC) a

WHERE ROWNUM <=4) b

WHERE RN > 0;

IN和EXISTS的用法和区别：

exists : 强调的是是否返回结果集，不要求知道返回什么

in 最大的区别在于 in引导的子句只能返回一个字段

select a.* from contract_basis a where exists(select 1 from signed_file b where a.id = b.con_basis_id); //查询在另一张表中有数据，有附件。

select a.* from contract_basis a where a.id in (select b.con_basis_id from signed_file b where a.id = b.con_basis_id);

DELETE FROM contract_basis_pro t1 WHERE NOT EXISTS (SELECT 1 FROM pro_bas_info t2 WHERE t1.pro_id = t2.pro_code); 查询在另一张中不存在的段。

按排序取出第一条数据：

with ti as (SELECT ID,MK_NO FROM (SELECT ID,MK_NO FROM MP_APP_DEPT WHERE PID = 'JGZNBM')

WHERE mk_no>'020202' order by mk_no)

select * from ti where rownum =1;

按排序取出第一条数据：

SELECT a.key_id,b.file_id FROM dm_process_upload a,mp_fs_file_info b WHERE a.attachment = b.file_id(+) ;

select to_char(sysdate,'YYYY-MM-DD HH24:MI:SS') d1 from dual;

to_date('2010-02-24 15:01:54','YYYY-MM-DD HH24:MI:SS')

select sysdate d1,trunc(sysdate) d2 from dual;//只要日期部分

select sysdate d1,EXTRACT(YEAR FROM sysdate) thisyear//日期的部分YEAR、MONTH,DAY、HOUR、MINUTE、SECOND

select date'2017-12-29'-a.branch_declare_date from special_evaluation a;

正则表达式：

SELECT * FROM pay_info WHERE 1=1 ORDER BY to_number(regexp_replace(doc_no, '[^0-9]')) DESC;//to_number的用法。

SELECT regexp_replace('20322323-07', '^[0-9]') FROM dual;

select regexp_replace('XX路1001弄12幢102室', 'd+幢', '') from dual 可取消第三个参数

sql字段为空则替换：

SELECT t.task_id,t.process_id,to_number(nvl(t.task_id,0))+to_number(nvl(t.process_id,0)) FROM material_plan t;

replace与translate都是替代函数：

select translate('abcdcefga','abc','wo') 返回值 from dual;//wodefgw

SELECT Replace('abcdcefga','abc','wo') 返回值 FROM dual;//wodcefga

只不过replace针对的是字符串，而translate针对的是单个字符,没有出现的，如‘c’也删除。

Union和Union All的区别:

1、Union，对两个结果集进行并集操作，不包括重复行，同时进行默认规则的排序；

2、Union All，对两个结果集进行并集操作，包括重复行，不进行排序；3、都是取select后的字段名作为统一字段名，union后的字段按顺序组合即可。

清除字段中有空格的字段：

select REPLACE(report_no, ' ', '') from contract_basis;

update contract_basis set report_no=REPLACE(report_no, ' ', '');

查询时间fan范围：

sysdate+1就是加一天
如果要加一小时的话就是sysdate+1/24
如果要加一分钟的话就是sysdate+1/24/60

--数据恢复：（delete闪回，drop回收站）
select * from user_recyclebin;--查询回收站内容

flashback table 要恢复的表名 to before drop;--恢复表

flashback table 表A to before drop rename to 表B;--从回收站恢复时重命名表(把表A重新恢复命名为表B)

1、 insert into 表名 (select * from 表名 as of timestamp to_timestamp('删除时间点','yyyy-mm-dd hh24:mi:ss'));-- 注意要保证主键不重复。

2、

--开启行移动功能

·alter table 表名 enable row movement

--恢复表数据
·flashback table 表名 to timestamp to_timestamp(删除时间点','yyyy-mm-dd hh24:mi:ss')

--关闭行移动功能 ( 千万别忘记 )

·alter table 表名 disable row movement