BlogJava-szhswl-文章分类-SQL

查询月的第一天及最后一天

宋针还 — Tue, 11 Dec 2007 11:53:00 GMT

SELECT TRUNC(TRUNC(SYSDATE, 'MONTH') - 1, 'MONTH') FIRST_DAY_LAST_MONTH,
       TRUNC(SYSDATE, 'MONTH') - 1 / 86400 LAST_DAY_LAST_MONTH,
       TRUNC(SYSDATE, 'MONTH') FIRST_DAY_CUR_MONTH,
       LAST_DAY(TRUNC(SYSDATE, 'MONTH')) + 1 - 1 / 86400 LAST_DAY_CUR_MONTH
FROM DUAL;

宋针还 2007-12-11 19:53 发表评论

有效的利用数据字典

宋针还 — Tue, 04 Dec 2007 07:12:00 GMT

        ORACLE的数据字典是数据库的重要组成部分之一，它随着数据库的产生而产生, 随着数据库的变化而变化,
体现为sys用户下的一些表和视图。数据字典名称是大写的英文字符。

        数据字典里存有用户信息、用户的权限信息、所有数据对象信息、表的约束条件、统计分析数据库的视图等。
我们不能手工修改数据字典里的信息。

　　很多时候，一般的ORACLE用户不知道如何有效地利用它。

　　dictionary　　　全部数据字典表的名称和解释，它有一个同义词dict
        dict_column　　全部数据字典表里字段名称和解释

如果我们想查询跟索引有关的数据字典时，可以用下面这条SQL语句:

SQL>select * from dictionary where instr(comments,index)>0;

如果我们想知道user_indexes表各字段名称的详细含义，可以用下面这条SQL语句:

SQL>select column_name,comments from dict_columns where table_name=USER_INDEXES;

依此类推，就可以轻松知道数据字典的详细名称和解释，不用查看ORACLE的其它文档资料了。

下面按类别列出一些ORACLE用户常用数据字典的查询使用方法。

一、用户

查看当前用户的缺省表空间
SQL>select username,default_tablespace from user_users;

查看当前用户的角色
SQL>select * from user_role_privs;

查看当前用户的系统权限和表级权限
SQL>select * from user_sys_privs;
SQL>select * from user_tab_privs;

二、表

查看用户下所有的表
SQL>select * from user_tables;

查看名称包含log字符的表
SQL>select object_name,object_id from user_objects
where instr(object_name,LOG)>0;

查看某表的创建时间
SQL>select object_name,created from user_objects where object_name=upper(&table_name);

查看某表的大小
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments
where segment_name=upper(&table_name);

查看放在ORACLE的内存区里的表
SQL>select table_name,cache from user_tables where instr(cache,Y)>0;

三、索引

查看索引个数和类别
SQL>select index_name,index_type,table_name from user_indexes order by table_name;

查看索引被索引的字段
SQL>select * from user_ind_columns where index_name=upper(&index_name);

查看索引的大小
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments
where segment_name=upper(&index_name);

四、序列号

查看序列号，last_number是当前值
SQL>select * from user_sequences;

五、视图

查看视图的名称
SQL>select view_name from user_views;

查看创建视图的select语句
SQL>set view_name,text_length from user_views;
SQL>set long 2000; 说明：可以根据视图的text_length值设定set long 的大小
SQL>select text from user_views where view_name=upper(&view_name);

六、同义词

查看同义词的名称
SQL>select * from user_synonyms;

七、约束条件

查看某表的约束条件
SQL>select constraint_name, constraint_type,search_condition, r_constraint_name
from user_constraints where table_name = upper(&table_name);

SQL>select c.constraint_name,c.constraint_type,cc.column_name
from user_constraints c,user_cons_columns cc
where c.owner = upper(&table_owner) and c.table_name = upper(&table_name)
and c.owner = cc.owner and c.constraint_name = cc.constraint_name
order by cc.position;

八、存储函数和过程

查看函数和过程的状态
SQL>select object_name,status from user_objects where object_type=FUNCTION;
SQL>select object_name,status from user_objects where object_type=PROCEDURE;

查看函数和过程的源代码
SQL>select text from all_source where owner=user and name=upper(&plsql_name);

宋针还 2007-12-04 15:12 发表评论

case的应用

宋针还 — Tue, 04 Dec 2007 06:39:00 GMT

见如下两SQL：
select sys_navigation_param_tb.*,
case when sys_navigation_param_tb.id in
(select sys_role_rihgts_tb.nav_param_id from sys_role_rihgts_tb where sys_role_rihgts_tb.role_id='1')
then 0
else 1 end flag
from sys_navigation_param_tb

select
case when (select count(id) from sys_role_rigths_tb) > 0 then sys_navigation_param_tb.group_name
else sys_navigation_param_tb.order_name
end
from sys_navigation_param_tb

宋针还 2007-12-04 14:39 发表评论

查锁表

宋针还 — Mon, 03 Dec 2007 09:25:00 GMT

select /*+ RULE */ ls.osuser os_user_name, ls.username user_name,
decode(ls.type, 'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock', 'TX',
'Transaction enqueue lock', 'UL', 'User supplied lock') lock_type,
o.object_name object, decode(ls.lmode, 1, null, 2, 'Row Share', 3,
'Row Exclusive', 4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive', null)
lock_mode,   o.owner, ls.sid, ls.serial# serial_num, ls.id1, ls.id2
from sys.dba_objects o, ( select s.osuser,   s.username,   l.type,
l.lmode,   s.sid,   s.serial#,   l.id1,   l.id2 from v$session s,
v$lock l where s.sid = l.sid ) ls where o.object_id = ls.id1 and   o.owner
<> 'SYS'   order by o.owner, o.object_name

宋针还 2007-12-03 17:25 发表评论

查找低劣SQL

宋针还 — Mon, 03 Dec 2007 09:24:00 GMT

下面是我收藏的一些查找bad sql的方法:

    select * from (select buffer_gets, sql_text
    from v$sqlarea
    where buffer_gets > 500000
    order by buffer_gets desc) where rownum<=30;

-- 执行次数多的SQL

    select sql_text,executions from
    (select sql_text,executions from v$sqlarea order by executions desc)
    where rownum<81;

-- 读硬盘多的SQL

    select sql_text,disk_reads from
    (select sql_text,disk_reads from v$sqlarea order by disk_reads desc)
    where rownum<21;

-- 排序多的SQL

    select sql_text,sorts from
    (select sql_text,sorts from v$sqlarea order by sorts desc)
    where rownum<21;

--分析的次数太多，执行的次数太少，要用绑变量的方法来写sql

    set pagesize 600;
    set linesize 120;
    select substr(sql_text,1,80) "sql", count(*), sum(executions) "totexecs"
    from v$sqlarea
    where executions < 5
    group by substr(sql_text,1,80)
    having count(*) > 30
    order by 2;

-- 游标的观察

    set pages 300;
    select sum(a.value), b.name
    from v$sesstat a, v$statname b
    where a.statistic# = b.statistic#
    and b.name = 'opened cursors current'
    group by b.name;
    select count(0) from v$open_cursor;
    select user_name,sql_text,count(0) from v$open_cursor
    group by user_name,sql_text having count(0)>30;

--查看当前用户&username执行的SQL

   select sql_text from v$sqltext_with_newlines where (hash_value,address) in
    (select sql_hash_value,sql_address from v$session where username='&username')
    order by address,piece;

宋针还 2007-12-03 17:24 发表评论

更新不同表相同字段不同值

宋针还 — Mon, 03 Dec 2007 09:22:00 GMT

UPDATE SA.SUBMIT SA
   SET SEND_STATE = (SELECT SEND_STATE
                       FROM PHS.SUBMIT
                      WHERE PHS.SUBMIT.ID = SA.ID
                        AND SUBSTR(SA.SEND_STATE, 15, 1) <>
                            AN.SUBMIT.SEND_STATE
                        AND SUBSTR(SA.SEND_STATE, 15, 1) IS NOT NULL)
WHERE SA.ISCHGSTATUS = 0 AND EXISTS
(SELECT 1
          FROM PHS.SUBMIT PHS
         WHERE PHS.ID = SA.ID
           AND SUBSTR(SA.SEND_STATE, 15, 1) <> PHS.SEND_STATE
           AND SUBSTR(SA.SEND_STATE, 15, 1) IS NOT NULL)

SQL说明：更新sa用户的submit表，与an用户的submit表相同字段但值不相同的数据。

宋针还 2007-12-03 17:22 发表评论

监控数据库性能SQL

宋针还 — Mon, 03 Dec 2007 09:19:00 GMT

    监视数据库性能的几个sql
　1. 监控事例的等待
　　select event,sum(decode(wait_Time,0,0,1)) "Prev",
　　sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
　　from v$session_Wait
　　group by event order by 4;
　2. 回滚段的争用情况
　　select name, waits, gets, waits/gets "Ratio"
　　from v$rollstat a, v$rollname b
　　where a.usn = b.usn;
　3. 监控表空间的 I/O 比例
　　select df.tablespace_name name,df.file_name "file",f.phyrds pyr,
　　f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
　　from v$filestat f, dba_data_files df
　　where f.file# = df.file_id
　　order by df.tablespace_name;
　4. 监控文件系统的 I/O 比例
　　select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
　　a.status, a.bytes, b.phyrds, b.phywrts
　　from v$datafile a, v$filestat b
　　where a.file# = b.file#;
　5.在某个用户下找所有的索引
　　select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
　　from user_ind_columns, user_indexes
　　where user_ind_columns.index_name = user_indexes.index_name
　　and user_ind_columns.table_name = user_indexes.table_name
　　order by user_indexes.table_type, user_indexes.table_name,
　　user_indexes.index_name, column_position;
　6. 监控 SGA 的命中率
　　select a.value + b.value "logical_reads", c.value "phys_reads",
　　round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO"
　　from v$sysstat a, v$sysstat b, v$sysstat c
　　where a.statistic# = 38 and b.statistic# = 39
　　and c.statistic# = 40;
　7. 监控 SGA 中字典缓冲区的命中率
　　select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",
　　(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
　　from v$rowcache
　　where gets+getmisses <>0
　　group by parameter, gets, getmisses;
　8. 监控 SGA 中共享缓存区的命中率，应该小于1%
　　select sum(pins) "Total Pins", sum(reloads) "Total Reloads",
　　sum(reloads)/sum(pins) *100 libcache
　　from v$librarycache;
　　select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
　　from v$librarycache;
   9.表空间碎片整理
      1,指定pctincrease不为0,则系统自动相邻自由盘区空间合并
      2,如果pctincrease为0,则系统不会自动实现相邻自由盘区空间合并,
        但是可以使用oracle命令 alter tablespace xxxx coalesce,强制
        相邻自由盘区空间合并.但是该命令不能合并被数据盘区分割的自由
        盘区.
      3,如果想彻底的合并所有的自由空间,只有对该表空间施行导出导入.以
        重新分配数据盘区

   10,重组表(使用move 命令可以减少行迁移,优化性能)
       可以删除旧表,复制数据,创建新表
       alter table xxx move
       tablespace new_tbs
       storage (initial xxM next xM pctincrease 0)
       pctfree 0 pctused 50
       initrans 2 nologging;

宋针还 2007-12-03 17:19 发表评论

求一列所有值的积

宋针还 — Mon, 03 Dec 2007 09:17:00 GMT

select power(2,sum(log(2,a))) from table;

宋针还 2007-12-03 17:17 发表评论

创建物化视图SQL

宋针还 — Mon, 03 Dec 2007 08:38:00 GMT

create materialized view v_acct_view refresh complete on demand
start with sysdate
next trunc(sysdate+1)+2/24
enable query rewrite
as
select area.areaname                   areaname,
       latn.Latnname                   latnname,
       count(cust.custid)              custid,
       to_char(vMain.updatedate,'yyyy-mm-dd')             Dday,
       to_char(vMain.updatedate,'yyyy-mm')                Ymonth,
       to_char(vMain.updatedate,'q')                      Qquater,
       count(vMain.acctid)             sum_acctid,
       sum(vMain.Jftotal)              sum_jftotal,
       sum(vMain.Jfusable)             sum_jfusable,
       sum(vMain.Jfconsume)            sum_jfconsume,
       sum(vMain.Jfinline)             sum_jfinline,
       sum(vMain.Jfsales)              sum_jfsales,
       sum(vMain.Jfencourage)          sum_Jfencourage,
       round(avg(vMain.Jftotal))       avg_jftotal,
       round(avg(vMain.Jfusable))      avg_jfusable,
       round(avg(vMain.Jfconsume))     avg_jfconsume,
       round(avg(vMain.Jfinline))      avg_jfinline,
       round(avg(vMain.Jfsales))       avg_jfsales,
       round(avg(vMain.Jfencourage))   avg_Jfencourage
from acct vMain
left join latn latn on latn.latnid = vMain.latnid
left join area area on area.areaid = vMain.areaid
group by
    latn.latnname,
    area.areaname,
    to_char(vMain.updatedate,'q') ,
    to_char(vMain.updatedate,'yyyy-mm'),
    to_char(vMain.updatedate,'yyyy-mm-dd')

宋针还 2007-12-03 16:38 发表评论

重复记录和处理

宋针还 — Mon, 03 Dec 2007 07:48:00 GMT

1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断
select * from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录
delete from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查找表中多余的重复记录（多个字段）
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录
delete from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

利用rowid重复记录的查询还可以用下面SQL：
select * from people p1
where p1.rowid not in (select max(rowid) from people p2 where p2.peopleId = p1.peopleId)

宋针还 2007-12-03 15:48 发表评论

同一列值在同一单无中显示

宋针还 — Mon, 03 Dec 2007 07:42:00 GMT

select chgdetail_id,
       chgdetail_custname
       min(decode(seq, 1, serv_devcode, NULL)) || ',' ||
       min(decode(seq, 2, serv_devcode, NULL)) || ',' ||
       min(decode(seq, 3, serv_devcode, NULL))
       chgdetail_roperatorid
from (select chgdetail_id,
               chgdetail_custname,
               serv_devcode,
               row_number() over(partition by chgdetail_id order by chgdetail_id asc) seq
          from (select c.id chgdetail_id,
                       c.custname chgdetail_custname,
                       serv.devcode serv_devcode
                  from chgdetail c
                  left outer join serv serv on c.racctid = serv.racctid
                 where
                 group by c.id,
                          c.custname,
                          serv.devcode))
where seq < 4
group by chgdetail_id,
     chgdetail_custname
SQL说明：当查询出结果的相连的数量(如上SQL只要求电话号前三位通过“，”相连)有限制或相同需求时，可用decode相连。

宋针还 2007-12-03 15:42 发表评论

同一列值在同一单元中显示之sys_connect_by_path的应用

宋针还 — Mon, 03 Dec 2007 07:19:00 GMT

select substr(max(sys_connect_by_path(upload_num_count, ',')), 2) result
from (select id, upload_num_count, rn, lead(rn) over(partition by id order by rn) rn1
          from (select 1 id, upload_num_count, row_number() over(order by upload_num_count desc) rn
                  from adp_yellowpage_sr))
start with rn1 is null
connect by rn1 = prior rn
SQL说明：将adp_yellowpage_sr表中的upload_num_count字段排序后显示在同一单元中，显示结果：
0,0,0,0,1,11,11,11,11,11,11,11,11,11,11,11,11,11,85,254,254,254,352,,,,,

select id,
       login_id,
       job_number,
       user_name,
       user_mobile,
       user_duty,
       user_status,
       max(ltrim(sys_connect_by_path(role_name, ','), ',')) role_name
from (select usertb.id,
               usertb.login_id,
               usertb.job_number,
               usertb.user_name,
               usertb.user_mobile,
               usertb.user_duty,
               usertb.user_status,
               roletb.role_name,
               row_number() over(partition by usertb.id order by roletb.role_name) rn
          from sys_user_info_tb usertb
          left outer join sys_user_role_tb userrole on userrole.user_id =
                                                       usertb.id
          left outer join sys_role_info_tb roletb on roletb.id =
                                                     userrole.role_id)
start with rn = 1
connect by prior rn + 1 = rn
       and prior id = id
group by id,
          login_id,
          job_number,
          user_name,
          user_mobile,
          user_duty,
          user_status
SQL说明：有三个表sys_user_role_tb用户信息表，sys_role_info_tb角色信息表，sys_user_role_tb用户角色关联表，
此SQL实现了role_name在同一单元中以“，”相连显示。

宋针还 2007-12-03 15:19 发表评论