Question

我有FM_TBL表，该表的month_id列是数字数据类型，日期以“ YYYYMM”格式存储。

我想比较上个月和当月的数据，并以此为基础找出当月插入FM_TABLE的新行数。

Answer 1

您可以使用减号

select SYS_DB_NAME, ENTITY_ID, MONTH_ID
from my_table 
where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( extract(month from sysdate), 2,'0')
minus  
select  SYS_DB_NAME, ENTITY_ID, MONTH_ID
from my_table 
where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( (extract(month from sysdate) -1) , 2,'0')

，如果需要行内容

select * from  my_table  m
inner join  (
    select SYS_DB_NAME, ENTITY_ID, MONTH_ID
    from my_table 
    where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( extract(month from sysdate), 2,'0')
    minus  
    select  SYS_DB_NAME, ENTITY_ID, MONTH_ID
    from my_table 
    where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( (extract(month from sysdate) -1) , 2,'0')
) T on m.SYS_DB_NAME = t.SYS_DB_NAME 
      AND m.ENTITY_ID = t.ENTITY_ID 
        AND m.MONTH_ID = t.MONTH_ID

，如果您只需要计数

select count(*) from  
inner join  (
    select SYS_DB_NAME, ENTITY_ID, MONTH_ID
    from my_table 
    where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( extract(month from sysdate), 2,'0')
    minus  
    select  SYS_DB_NAME, ENTITY_ID, MONTH_ID
    from my_table 
    where MONTH_ID = to_char(sysdate, 'YYYY') || lpad( (extract(month from sysdate) -1) , 2,'0')
) T

Answer 2

您可以使用not exists：

select count(*)
from fm_tbl t
where t.monthid = to_char(sysdate, 'YYYYMM') and
      not exists (select 1
                  from fm_tbl t2
                  where t2.monthid = to_char(sysdate - interval '1' month, 'YYYYMM') and
                        t2.cust_srcid = t.cust_srcid
                 );

如果可以在给定的月份内回头客，请使用count(distinct cust_srcid)。

根据月份比较并获取插入表中的新数据

2 个答案: