Oracle 查询连接日期

Question

I have the following query:

select * 
  from mytable 
 where to_char(mydate,'mm/dd/yyyy') between ('05/23/2013') 
                                        and ('06/22/2013')

I need to change it to make dynamically so that I won't modify it every month from 05/23/2013 to 06/23/2013 for example:

('05/23/' + (select to_char(sysdate, 'yyyy') from dual))

but this is giving an error. Any suggestions?

What I need to do: Every month I need to run this query to get the records between 23 ^rd of this month and 23 ^rd of the last month.

Answer 1

Oracle uses || as the concatenation operator :

('05/23/' || (select to_char(sysdate, 'yyyy') from dual))

BTW, David is right. If you really want to compare string representations of dates (but why?), use a date format that is ordered the same way as dates:

to_char(mydate,'yyyy/mm/dd')

Answer 2

You're performing a comparison on strings, not on dates, so your code doesn't work the way you think it does.

Based on the string logic, "05/23/2000" is between "05/22/2013" and "06/24/2000".

Keep the data types as date and Oracle will get the comparison right.

Possibly what you want is:

select *
from   my_table
where  mydate >= add_months(trunc(sysdate,'MM'),-1)+22 and
       mydate <  trunc(sysdate,'MM')+22

but it's difficult to tell without a description of what the requirement actually is.

Answer 3

How about this one?

SELECT '(''05/23/'''||to_char(sysdate, 'yyyy')||'''' FROM DUAL

Have not testet because I have no Oracle database right now, needs checking for quote escapes...

Do you need exact days from the month? You can also substract days from sysdate:

SELECT (sysdate - 30) FROM DUAL

Answer 4

您也可以使用 concat 函数

concat('05/23/', (select to_char(sysdate, 'yyyy') from dual))