Comments on: If you can’t do it in PL/SQL, do it in SQL

By: Boneisteist

Boneisteist — Sat, 06 Aug 2011 11:33:24 +0000

Tree walking is possible in (some versions of) some other rdbms’s, with the advent of Common Table Expressions (at least, I think that’s what they call them!), which Oracle 11g has too (only it’s an advance of the Subquery-factoring we’ve had for a while now!).

testing
  1
2   3

thanks for the tip!

By: mikesmithers

mikesmithers — Sat, 06 Aug 2011 10:57:36 +0000

Boneist,

thanks for your persistence.
Your solution is far more elegant than mine. So what if tree walking ( connect by prior etc) is proprietary to Oracle, they started it with their fancy date formats !
In any case, the Universal Translator has long given up in despair and wandered off in the direction of the pub.
Incidentally, formatting code in wordpress is possible if you use the “sourcecode” “/sourcecode” tags. You need to enclose them in square brackets ( and I can’t drop them into this comment cos it treats them as tags and you don’t see them ! Yes, it took me a while to work that one out as well.

By: Boneist

Boneist — Thu, 04 Aug 2011 14:26:09 +0000

ah, I worked it out, it was the > sign which was confusing Wordpress. Last attempt at getting the right sql (if it doesn't change the &> into a greater than sign, please replace manually before running!):

with dates as (select trunc(sysdate, 'mm') + 21 + level dt -- 23rd of the month and onwards
               from   dual
               connect by level <= 5
               union
               select last_day(trunc(sysdate)) + level dt -- 1st of next month and onwards
               from   dual
               connect by level <= 5)
select min(dt), min(case when dt > last_day(trunc(sysdate)) then dt end)
from   dates
where  to_char(dt, 'DY', 'nls_date_language=english') not in ('SAT', 'SUN')
and    dt not in (select bh_date from bank_holidays);

I wish there was a preview on comments available!

By: Boneist

Boneist — Thu, 04 Aug 2011 14:22:11 +0000

I think I'm going to give up; clearly I can't master the art of C&P! This is hopefully the correct version, using sysdate etc:

with dates as (select trunc(sysdate, 'mm') + 21 + level dt -- 23rd of the month and onwards
               from   dual
               connect by level <= 5
               union
               select last_day(trunc(sysdate)) + level dt -- 1st of next month and onwards
               from   dual
               connect by level  last_day(trunc(sysdate)) then dt end)
from   dates
where  to_char(dt, 'DY', 'nls_date_language=english') not in ('SAT', 'SUN')
and    dt not in (select bh_date from bank_holidays)

*hangs head*

By: Boneist

Boneist — Thu, 04 Aug 2011 14:20:12 +0000

Gosh, the middle bit of my query got eaten up somewhere along the line! It should be (I've used sysdate; obviously that'd need to be changed to a parameter etc)

with dates as (select trunc(:p_date) + 21 + level dt -- 23rd of the month and onwards
               from   dual
               connect by level <= 5
               union
               select last_day(trunc(:p_date)) + level dt -- 1st of next month and onwards
               from   dual
               connect by level  last_day(trunc(:p_date)) then dt end)
select min(dt), max(dt)
from   dates
where  to_char(dt, 'DY', 'nls_date_language=english') not in ('SAT', 'SUN')
and    dt not in (select bh_date from bank_holidays);

By: Boneist

Boneist — Mon, 01 Aug 2011 09:16:00 +0000

An alternative would be:

with dates as (select trunc(:p_date) + 21 + level dt -- 23rd of the month and onwards
               from   dual
               connect by level <= 5
               union
               select last_day(trunc(:p_date)) + level dt -- 1st of next month and onwards
               from   dual
               connect by level  last_day(trunc(:p_date)) then dt end)
from   dates
where  to_char(dt, 'DY', 'nls_date_language=english') not in ('SAT', 'SUN')
and    dt not in (select bh_date from bank_holidays)