Sql on darcyjoven

Oracle in嵌套错误字段问题

Wed, 14 Oct 2026 00:00:00 +0000

假设存在两个表：

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create table darcy1(
	ima01 varchar(40),
	ima02 varchar(40),
	ima021 varchar(200)
);
create table darcy2(
	ima01 varchar(40),
	ima02 varchar(40)
)

运行下面代码不会出错，darcy2虽然没有ima021字段，但是SQL能匹配到darcy1有ima021字段，所以ima021字段被省略了。

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select * from darcy1 where (ima01,ima02,ima021) in (
	select ima01,ima02,ima021 from darcy2 where ima01 like 'M%'
)

以上代码结果等价于：

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select * from darcy1 where (ima01,ima02) in (
	select ima01,ima02 from darcy2 where ima01 like 'M%'
)

所以嵌套的时候，如果两个表字段有可能重复，子查询中请尽量用表名.字段的形式。

Oracle表空间查询与增加

Wed, 14 Oct 2026 00:00:00 +0000

表空间查询

system/sys 登录sqlplus后运行@q_tbsFREE

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select * from (
 select t.tablespace_name,t.owner, t.segment_name, t.segment_type, sum(t.bytes / 1024 / 1024) mb
 from dba_segments t
 where t.segment_type='TABLE'
	AND tablespace_name ='TEMPTABS'
 group by t.tablespace_name,t.OWNER, t.segment_name, t.segment_type
) t
order by t.mb desc;

查询表空间文件

查询命令@q_datafile

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select t.tablespace_name,
 d.file_name,
 d.bytes / 1024 / 1024 as size_mb,
 d.autoextensible,
 d.maxbytes / 1024 / 1024 as max_size_mb
 from dba_tablespaces t
 join dba_data_files d
 on t.tablespace_name = d.tablespace_name
 order by t.tablespace_name, d.file_name;

增加表空间

alter tablespace xx add datafile 'xxx.dbf' size 4G;

默认账户密码

TOPGP system/manager
T100 system/tiptop100

Oracle高级查询sql

Wed, 14 Oct 2026 00:00:00 +0000

`pivot`列转行

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WITH a AS
 (SELECT 'darcy' na, '语文' ke, 23 score FROM dual),
b AS
 (SELECT 'tom', '语文', 23 FROM dual),
c AS
 (SELECT 'darcy', '数学', 24 FROM dual),
d AS
 (SELECT * FROM a UNION ALL SELECT * FROM b UNION ALL SELECT * FROM c)
SELECT na, 语文, 数学
 FROM (SELECT na, ke, score FROM d)
PIVOT (SUM(score) FOR ke IN('语文' AS 语文, '数学' AS 数学));

`unpivot`行转列

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WITH a AS
 (SELECT 'darcy' na, '90' 语文, '80' 数学, '87' 英语 FROM dual)
SELECT na, ke, score FROM a UNPIVOT(score for ke in(语文, 数学, 英语))

keep 聚合的基础上再取最值

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SELECT 
tc_bmj03,tc_bmj04,MAX(tc_bmj01) KEEP(dense_rank LAST order BY tc_bmj09) max01
FROM tc_bmj_file
WHERE tc_bmj11 ='2'
GROUP BY tc_bmj03,tc_bmj04

over 分析

语法：rank()/dense_rank over(partition by A order by B)

over是一种分析函数，根据字段A对结果进行分区，在各分区内按照字段进行排序；

over不能单独使用，需要与row_number()，rank()和dense_rank，lag()和lead(),sum()等配合使用

说明：

over()在什么条件之上
partition by 按哪个字段划分组
order by 按哪个字段排序注意：
使用rank()/dense_rank() 时，必须要带order by否则非法
rank(): 跳跃排序，如果有两个第一级时，接下来就是第三级
dense_rank(): 连续排序，如果有两个第一级时，接下来仍然是第二级

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SELECT fan01,
 fan03,
 fan04,
 fan15,
 dense_rank() OVER(PARTITION BY fan01 ORDER BY fan03 DESC, fan04 DESC) r
 FROM fan_file
 WHERE fan041 IN ('0', '1')
 AND fan05 IN ('1', '2')
 AND fan01 = 'FLYG200001'

lag 偏移函数

可以查询上几条数据,下几条数据,适合查上下站资料

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SELECT fan01,
 fan03,
 fan04,
 fan15,
			 LAG(fan03||fan04) OVER (ORDER BY fan03 DESC ,fan04 DESC) a1,
			 LAG(fan03||fan04,2,0) OVER (ORDER BY fan03,fan04) a2
 FROM fan_file
 WHERE fan041 IN ('0', '1')
 AND fan05 IN ('1', '2')
 AND fan01 = 'FLYG200001'
	 ORDER BY fan03,fan04

`instr` 字符串匹配函数

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SELECT 
 INSTR('123456789','2'), -- 返回：2
 INSTR('123456654321','66'), -- 返回：6
 INSTR('123456654321','66',6), -- 返回：6
 INSTR('123456654321','66',8), -- 返回：0
 INSTR('11223344','2',1,2), -- 返回：4
 INSTR('11223344','2',2,3), -- 返回：0
 INSTR('11223344','2',-1,2), -- 返回：3
 INSTR('11223344','2',-6,1), -- 返回：3
 INSTR('11223344','2',-6,2) -- 返回：0
 FROM DUAL ;

istagg 聚合为一条数据

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LISTAGG(字段名,',') WITHIN GROUP( ORDER BY 字段名)
listagg(字段名,',') within GROUP (order by 字段名) over (partition by 字段名) rank

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with temp as(
select 500 population, '中国' nation ,'江苏' city from dual union all
select 1500 population, '中国' nation ,'上海' city from dual union all
select 500 population, '中国' nation ,'北京' city from dual union all
select 1000 population, '美国' nation ,'纽约' city from dual union all
select 500 population, '美国' nation ,'波士顿' city from dual union all
select 500 population, '日本' nation ,'东京' city from dual
)
select population,
nation,
city,
listagg(city,',') within GROUP (order by city) over (partition by nation) rank
from temp

递归

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SELECT LEVEL,
 CONNECT_BY_ISLEAF 是否无下阶料,
 bmb01,
 bmb03,
 SYS_CONNECT_BY_PATH(bmb01, '/') 路径,
 CONNECT_BY_ROOT(bmb01) root
 FROM bmb_file
 WHERE bmb04 <= SYSDATE
 AND (bmb05 IS NULL OR bmb05 > SYSDATE)
 START WITH bmb01 LIKE 'AA0011A3CR' --从这个资料开始
CONNECT BY PRIOR bmb03 = bmb01 --下笔资料的bmb03 和当前bmb01一样

Oracle锁表查询

Wed, 14 Oct 2026 00:00:00 +0000

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SELECT
 l.session_id,
 l.locked_mode,
 l.oracle_username,
 l.os_user_name,
 o.object_name,
 s.sid,
 s.serial#,
 s.logon_time
FROM
 v$locked_object l,
 dba_objects o,
 v$session s
WHERE
 l.object_id = o.object_id
 AND l.session_id = s.sid;

ALTER SYSTEM KILL SESSION 'sid,serial#';

Oracle运维常用命令

Wed, 14 Oct 2026 00:00:00 +0000

清除查询缓存

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ALTER SYSTEM FLUSH SHARED_POOL;
ALTER SYSTEM FLUSH BUFFER_CACHE;
ALTER SYSTEM FLUSH GLOBAL CONTEXT;

分析表结构

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--① 分析表的所有字段，所有索引，所有索引字段。其中：① = ②
analyze table student compute statistics;
--② 分析表的所有字段，所有索引，所有索引字段。其中：① = ②
analyze table student compute statistics for table for all indexes for all columns;
--③ 只分析所有有索引的字段
analyze table student compute statistics for table for all indexes for all indexed columns;

--④ 抽样估算法
analyze table student estimate statistics sample 20 percent;

--⑤ 删除分析数据
analyze table student delete statistics;
analyze table student delete statistics for table for all indexes for all indexed columns;

--查看表的统计信息
select table_name,num_rows,blocks,empty_blocks from user_tables where table_name='student';

analyze table glaq_t compute statistics;

优化器

优先查询前 25 笔

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SELECT /*+ FIRST_ROWS(25) */ employee_id, department_id
FROM hr.employees
WHERE department_id > 50;

强制走索引

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SELECT /*+index(a)*/ * FROM sfb_file
LEFT JOIN sfa_file ON sfa01= sfb01
LEFT JOIN ima_file a ON a.ima01 = sfb05
LEFT JOIN ima_file b ON b.ima01 = sfa03
LEFT JOIN ima_file c ON c.ima01 = sfa27

查询被删除的表

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select object_name,original_name,partition_name,type,ts_name,createtime,droptime
from recyclebin;

恢复删除的表

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flashback table test_drop to before drop;或
flashback table "BIN$hgcd$0" to before drop;

清理临时表空间

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set linesize 132;
set pagesize 0;
set timing off;
spool drop_tables.sql;
SELECT 'drop table '||OWNER||'.'||TABLE_name||' purge;' FROM dba_tables WHERE tablespace_name='TEMPTABS';
spool off;
@drop_tables.sql;

查询某个时间之前的表状态（闪回）

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select * from sfb_file
as of timestamp to_timestamp('2021-09-22 15:30:00','yyyy-mm-dd hh24:mi:ss')

查询单个 table 占用磁盘空间

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select * from (
 select t.tablespace_name,t.owner, t.segment_name, t.segment_type, sum(t.bytes / 1024 / 1024) mb
 from dba_segments t
 where t.segment_type='TABLE'
	AND tablespace_name ='TEMPTABS'
 group by t.tablespace_name,t.OWNER, t.segment_name, t.segment_type
) t
order by t.mb desc;

在备份中仅恢复部分表

准备号 dmp 备份文件
建立临时测试库

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sqlplus system/manager@topprod
 create user test1 identified by test1 default tablespace dbs1;
 grant connect,resource to test1;
 commit;

恢复表

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imp system/manager@topprod file=/u3/backup/Wed/exp_KT_20210203.dmp
 fromuser=kt touser=test1 tables=gen_file,eci_file

增加表空间

管理员账号登陆，运行@q_tbsFREE命令查询表空间是否足够
运行@q_datefile查询表空间文件位置
增加合适大小表空间文件

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alter tablespace xx add datafile 'xxx.dbf' size 4G;

Oracle最近运行SQL查询

Wed, 14 Oct 2026 00:00:00 +0000

最近运行平均时间较长SQL查询

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select *
 from (select sa.SQL_TEXT,
 sa.SQL_FULLTEXT,
 sa.EXECUTIONS "执行次数",
 round(sa.ELAPSED_TIME / 1000000, 2) "总执行时间",
 round(sa.ELAPSED_TIME / 1000000 / sa.EXECUTIONS, 2) "平均执行时间",
 sa.COMMAND_TYPE,
 sa.PARSING_USER_ID "用户ID",
 u.username "用户名",
 sa.HASH_VALUE
 from v$sqlarea sa
 left join all_users u
 on sa.PARSING_USER_ID = u.user_id
 where sa.EXECUTIONS > 0
 order by (sa.ELAPSED_TIME / sa.EXECUTIONS) desc)
 where rownum <= 50;

最近运行SQL查询

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SELECT * from V$SQL WHERE sql_id IS NOT NULL;

Sql on darcyjoven

Oracle in嵌套错误字段问题

Oracle表空间查询与增加

表空间查询

查询表空间文件

增加表空间

默认账户密码

Oracle高级查询sql

pivot列转行

unpivot行转列

keep 聚合的基础上再取最值

over 分析

lag 偏移函数

instr 字符串匹配函数

istagg 聚合为一条数据

递归

Oracle锁表查询

Oracle运维常用命令

清除查询缓存

分析表结构

优化器

查询被删除的表

清理临时表空间

查询某个时间之前的表状态（闪回）

查询单个 table 占用磁盘空间

在备份中仅恢复部分表

增加表空间

Oracle最近运行SQL查询

最近运行平均时间较长SQL查询

最近运行SQL查询

`pivot`列转行

`unpivot`行转列

`instr` 字符串匹配函数