
--条件查询
select * from Kess a where a.UUID = 'b487-757';
 
nner join(等值连接) 只返回两个表中联结字段相等的行
left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记录
right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录
INNER JOIN 语法：
INNER JOIN 连接两个数据表的用法：
select * FROM 表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号
 
--去重
select distinct(a.cust_code) from otc_match_app a where a.app_date=20181108 and to_char(a.app_timestamp,'mmddhhMM')<'11080901';
 
--查数据库中所有的表的话
select count(*) FROM dba_tables；
 
--模糊查询
select * from Persons where City like 'N%';
 
--以逆字母顺序显示公司名称，并以数字顺序显示顺序号：asc升序-默认、desc降序
select Company, Number FROM kess order by Company DESC, Number ASC；
 
--资金总和，分组
select Customer,SUM(OrderPrice) FROM Orders
GROUP BY Customer
 
 
 
--插入语句
INSERT INTO 表名称 VALUES (值1, 值2,....);
 
--也可以指定所要插入数据的列：
INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....);
 
--修改语句
UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值;
 
UPDATE Person SET Address = 'Zhongshan 23', City = 'Nanjing' where  LastName = 'Wilson'
 
 
--删除数据：删除满足条件的记录
DELETE from KESS where UUID = 'b487-7';
 
--删除所有数据，不会影响表结构，不会记录日志，数据不能恢复--》删除很快
truncate table KESS;
 
 
--删除所有数据，包括表结构一并删除，不会记录日志，数据不能恢复--》删除很快
drop table KESS;

1.解锁用户

alter user test account unlock;

2.修改用户密码

alter user sys  identified by pswd12asd1a;

3.查看所有用户的缺省表空间

SELECT username, default_tablespace FROM dba_users;

4.查看表空间路径，名称，大小

select file_name,tablespace_name,bytes from dba_data_files;

5.查看数据库大小

select round(sum(bytes)/1024/1024/1024,2) as size_GB from dba_segments;

6.查询数据库连接数-总数


select inst_id, resource_name, current_utilization, max_utilization, initial_allocation, limit_value
from gv$resource_limit
where resource_name in('processes','sessions')
order by inst_id, resource_name;

7.查询数据库连接数-详细连接数


select inst_id, username, machine, module, program, service_name, count(*)
from gv$session
where type<>'BACKGROUND'
and username not in ('SYS','PUBLIC','SYSRAC','DBSNMP')
and status<>'KILLED'
group by service_name, username, inst_id, machine, module, program
order by service_name, username, inst_id, machine, module, program;

8.查询字符集


SELECT
    SYS_CONTEXT('USERENV', 'LANG')                           AS LANG,
    SYS_CONTEXT('USERENV', 'LANGUAGE')                       AS LANGUAGE
FROM
    dual;

9.数据库启停


1. 使用root用户通过SSH登录BIEE资料库服务器shell命令控制台
2. 切换到oracle用户下：
#su - oracle
3. 使用数据库管理员连接oracle数据库：
$sqlplus / as sysdba
4. 启动数据库：
>startup
5. 退出数据库连接 ：
>exit
 
 
 
注：关闭数据库：
关闭监听服务：
$lsnrctl stop
使用数据库管理员连接oracle数据库：
$sqlplus / as sysdba
关闭数据库：
>shutdown immediate
退出数据库连接 ：
>exit
 
 
 
6. 启动数据库监听：
$lsnrctl    start
7. 查看服务启动状态，看到以下回显信息，服务启动成功：
$lsnrctl    status

10.修改密码过期时间


 
sqlplus / as sysdba
 
SELECT username, PROFILE FROM dba_users;
 
 
查看密码周期
SELECT * FROM dba_profiles s WHERE s.profile='DEFAULT' AND resource_name = 'PASSWORD_LIFE_TIME';
 
 
 
修改为密码周期为不限制；
 
alter profile default limit password_life_time unlimited;
 
 
 
6、如果已经提示：java.sql.SQLException: ORA-28001: 口令已经失效这样的错误，还需要修改一下密码，改为本密码就可以。
 
alter user 用户名 identified by 旧密码;
 
 
 
commit;

11.通过表名-->找用户

select owner,table_name from dba_tables where table_name='RENWEI';

12.性能排查sql a.查看耗时SQL;b.查看CPU耗时最多的SQL语句;c.查看消耗磁盘读取最多的SQL


定位问题
 
 
1、通过PID与v$process、v$session两张视图快速定位出语句的sql_id，如下：
 
 
SQL> select sql_id from v$session where paddr= (select addr from v$process  where spid ='29889');
SQL_ID
-------------
59vtwwcggzcwh
 
 
2、通过sql_id查看具体sql
 
 
SQL> select sql_text from v$sql where sql_id='59vtwwcggzcwh';
SQL_TEXT
--------------------------------------------------------------------------------
select * from scott.t3 where name=dbms_random.string('u', 10)
 
 
 
--1、查看耗时SQL
 
select *
 
from (select v.sql_id,
 
v.child_number,
 
v.sql_text,
 
v.elapsed_time,
 
v.cpu_time,
 
v.disk_reads,
 
rank() over(order by v.elapsed_time desc) elapsed_rank
 
from v$sql v) a
 
where elapsed_rank <= 10;
 
-- 2.查看CPU消耗时间最多的前10条SQL语句
 
select *
 
from (select v.sql_id,
 
v.child_number,
 
v.sql_text,
 
v.elapsed_time,
 
v.cpu_time,
 
v.disk_reads,
 
rank() over(order by v.cpu_time desc) elapsed_rank
 
from v$sql v) a
 
where elapsed_rank <= 10;
 
--3.查看消耗磁盘读取最多的前10条SQL语句
 
select *
 
from (select v.sql_id,
 
v.child_number,
 
v.sql_text,
 
v.elapsed_time,
 
v.cpu_time,
 
v.disk_reads,
 
rank() over(order by v.disk_reads desc) elapsed_rank
 
from v$sql v) a
 
where elapsed_rank <= 10;

13.查询表空间-数据文件可扩展


SELECT
    S.TABLESPACE_NAME,
    S.CURSIZE   AS "CURRENT_TBS_SIZE(MB)",
    TRUNC(NVL2(F.FREE, S.CURSIZE - F.FREE, S.CURSIZE)) AS "USED_SIZE(MB)",
    NVL(F.FREE, 0) AS "CURRENT_FREE_SIZE(MB)",
    CASE
        WHEN S.MAXSIZE - S.CURSIZE > 0 THEN
            S.MAXSIZE - S.CURSIZE
        ELSE
            0
    END AS "EXTENSIBLE_FREE_SIZE(MB)",
    S.MAXSIZE   AS "MAX_SIZE(MB)",
    LPAD(TO_CHAR(TRUNC(NVL2(F.FREE, S.CURSIZE - F.FREE, S.CURSIZE) * 100 / S.MAXSIZE)), 3, ' ')
    || '%' AS "PCT_USED"
FROM
    (
        SELECT
            TABLESPACE_NAME,
            TRUNC(SUM(BYTES) / 1024 / 1024) AS CURSIZE,
            TRUNC(SUM(
                CASE
                    WHEN(MAXBYTES < BYTES
                         OR MAXBYTES IS NULL
                         OR AUTOEXTENSIBLE = 'NO') THEN
                        BYTES
                    ELSE
                        MAXBYTES
                END
            ) / 1024 / 1024) AS MAXSIZE
        FROM
            DBA_DATA_FILES
        GROUP BY
            TABLESPACE_NAME
        UNION ALL
        SELECT
            TABLESPACE_NAME,
            TRUNC(SUM(BYTES) / 1024 / 1024) AS CURSIZE,
            TRUNC(SUM(
                CASE
                    WHEN(MAXBYTES < BYTES
                         OR MAXBYTES IS NULL
                         OR AUTOEXTENSIBLE = 'NO') THEN
                        BYTES
                    ELSE
                        MAXBYTES
                END
            ) / 1024 / 1024) AS MAXSIZE
        FROM
            DBA_TEMP_FILES
        GROUP BY
            TABLESPACE_NAME
    ) S,
    (
        SELECT
            TABLESPACE_NAME,
            TRUNC(SUM(BYTES) / 1024 / 1024) AS FREE
        FROM
            DBA_FREE_SPACE
        GROUP BY
            TABLESPACE_NAME
    ) F
WHERE
    F.TABLESPACE_NAME (+) = S.TABLESPACE_NAME
ORDER BY
    7 DESC;

14.数据库备份

1.查看管理理员目录

select * from dba_directories;

2.赋于要导出数据表的所属用户权限

sql>grant read,write on directory dpdata1 to RENWEI;

3.备份 :RENWEI

expdp system/passwd123@orcl directory=PUMP_DIR dumpfile=RENWEI20221008.dmp logfile=RENWEI20221008.log schemas=RENWEI

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