-- oracle上一些查询表和字段语句

-- oracle上一些查询表和字段语句

--查询表空间中表数据占用情况语句

SELECT 
     OWNER
    ,TABLESPACE_NAME
    ,SEGMENT_NAME
    ,SUM(BYTES) / 1024 / 1024 AS TOALL
FROM DBA_SEGMENTS
WHERE SEGMENT_NAME = 'TB_DSS_APP_BI_KPI_D1901054'
GROUP BY  
    SEGMENT_NAME
--HAVING SUM(BYTES) / 1024 / 1024 >= 10
ORDER BY 
    TOALL DESC;

-------表大小

select 
    (tt.free_gb + tt1.use_gb)
from 
    (
        select 
             t.tablespace_name
            ,sum(t.bytes) / 1024 / 1024 / 1024 as free_gb
        from user_free_space t, user_users s
        where 
            t.tablespace_name = s.default_tablespace
        group by 
            t.tablespace_name
    ) tt,(
            select 
                sum(t.bytes) / 1024 / 1024 / 1024 as use_gb
            from user_segments t
        ) tt1
;

----查用户下表

 select * from all_TABLES where lower(owner) like '%dic_bi%'； 

----查用户下表对应字段

select 
     table_name
    ,column_name
    ,data_type
from ALL_tab_columns 
where 
    lower(owner) like '%dic_bi%' 
    and lower(table_name) like 'tb_dss_app_bi_kpi%' 
order by 
     table_name
    ,column_name
;

-- 去重语句

delete from ldc_data.tb_xw_lc_xhzwfx_02 t 
where exists (
                select * 
                from  ldc_data.tb_xw_lc_xhzwfx_02 t2 
                where  
                    t.latn_id=t2.latn_id 
                    and t.prd_inst_id=t2.prd_inst_id  
                    and t.rowid>t2.rowid
            )
;

--  循环

begin  
     for cu_latn in (select  latn_id  from  eda.tb_b_dim_latn) loop
      execute immediate 'insert into  eda.tem_chenbao_hlr_day_20200703
select  /*+ parallel(a,8) */
20200703 day_id,a.latn_id,b.latn_name,b.order_id,count(distinct a.prd_inst_id) kj,'||cu_latn.latn_id||' old_latn_id        
from tb_b_ft_hlr_day_'||cu_latn.latn_id||' a,
     tb_b_dim_latn_city b         
where a.act_flag=1 and a.day=3 and a.latn_id=b.latn_id
group by a.latn_id,b.latn_name,b.order_id';
commit;
end loop;
end;
/

--  oracle添加注释

 COMMENT ON COLUMN STUDENT_INFO.STU_ID IS '学号'; 

-- decode函数

 decode(条件，值1，返回值1，值2，返回值2，...值n,返回值n，缺省值)