Oracle SQL How can I write this Join with less code? - sql

Question

Hello Oracle experts I have a question on how to join two tables correctly.
My first table describes an leave category, the minimum years of service time required for new max vacation leave rollover amount and the max rollover numbers.
PTRLVAC_LCAT_CODE PTRLVAC_YEAR PTRLVAC_ROLL_MAX_HRS
C1 0 80
C1 2 88
C1 5 128
P3 0 120
P3 2 128
P3 5 168
The next table details the employee id, hire date, and leave category
PEBEMPL_PIDM PEBEMPL_HIRE_DATE PEBEMPL_LCAT_CODE
1234 01/09/2017 P3
3214 02/01/2014 C1
The join that I have right now relies on a CTE and I'm not sure if it's the easiest solution.
**I've included the tables here as CTEs
with ptrlvac as(
select 'C1' ptrlvac_lcat_code
,0 ptrlvac_year
,80 ptrlvac_roll_max_hrs
from dual union all
select 'C1', 2, 88 from dual union all
select 'C1', 5, 128 from dual union all
select 'P3', 0, 120 from dual union all
select 'P3', 5, 128 from dual union all
select 'P3', 2, 168 from dual
) , pebempl as(
select 1234 pebempl_pidm
,to_date('09-JAN-2017', 'DD-MON-YYYY') pebempl_hire_date
,'P3' pebempl_lcat_code
from dual
UNION ALL
select 3214, to_date('01-FEB-2014','DD-MON-YYYY'), 'C1' from dual
) ,leave as(
select a.ptrlvac_lcat_code
,a.ptrlvac_year
,a.ptrlvac_roll_max_hrs
,row_number()
over(partition by a.ptrlvac_lcat_code
order by a.ptrlvac_year) rn
from ptrlvac a
)
,leave_rules as(
select a.ptrlvac_lcat_code
,a.ptrlvac_year year_start
,nvl(b.ptrlvac_year, 100)-1 year_end
,a.ptrlvac_roll_max_hrs
from leave a
left join leave b
on a.ptrlvac_lcat_code = b.ptrlvac_lcat_code
and a.rn = b.rn - 1
)
select distinct pebempl_pidm
,pebempl_hire_date
,floor(months_between(to_date(:seldate, 'DD-MON-YYYY'), pebempl_hire_date) / 12) as service_years
,pebempl_lcat_code as lcat
,b.ptrlvac_roll_max_hrs
from pebempl a
inner join leave_rules b
on a.pebempl_lcat_code = b.ptrlvac_lcat_code
and floor(months_between(to_date(:seldate, 'DD-MON-YYYY'), pebempl_hire_date) / 12) between b.year_start and b.year_end
Any help to save some keystrokes would be greatly appreciated.
Thanks in advance.

Answer 1

I'm not sure if this does what you want:
select
t2.PEBEMPL_PIDM,
t1.PTRLVAC_ROLL_MAX_HRS
from test1 t1, test2 t2
where
t1.PTRLVAC_LCAT_CODE = t2.PEBEMPL_LCAT_CODE and
t1.PTRLVAC_YEAR =
(select max(t1s.PTRLVAC_YEAR) from test1 t1s
where t1s.PTRLVAC_LCAT_CODE = t2.PEBEMPL_LCAT_CODE
and (sysdate-PEBEMPL_HIRE_DATE)/365 >= t1s.PTRLVAC_YEAR);
Here are the results I got based on your test data:
PEBEMPL_PIDM PTRLVAC_ROLL_MAX_HRS
------------ --------------------
3214 88
1234 120
Bobby

Answer 2

Had this thought over lunch, further reducing #BobbyDurret's answer:
select
t2.PEBEMPL_PIDM,
max(t1.PTRLVAC_ROLL_MAX_HRS)
from ptrlvac t1, pebempl t2
where
t1.PTRLVAC_LCAT_CODE = t2.PEBEMPL_LCAT_CODE and
(sysdate-PEBEMPL_HIRE_DATE)/365 >= t1.PTRLVAC_YEAR
group by t2.PEBEMPL_PIDM
Assumes the Max_Hrs always increases for more years of service.

Answer 3

Instead of using row_number and filtering in a separate CTE, use lead:
with leave_rules as
(
select a.ptrlvac_lcat_code
,a.ptrlvac_year as year_start
,a.ptrlvac_roll_max_hrs
,lead(ptrlvac_year,1,10000) over (partition by ptrlvac_lcat_code
order by ptrlvac_year)
as year_end
from ptrlvac a
)
select distinct pebempl_pidm
,pebempl_hire_date
,floor(months_between(sysdate, pebempl_hire_date) / 12) as service_years
,pebempl_lcat_code as lcat
,b.ptrlvac_roll_max_hrs
from pebempl a
inner join leave_rules b
on a.pebempl_lcat_code = b.ptrlvac_lcat_code
and floor(months_between(sysdate, pebempl_hire_date) / 12) between year_start and year_end
Combines your 2 CTE's to compute "leave_rules" into 1. I just put sysdate for the date variable so I could test easily - you probably want to use the bind variables as you originally had.