How do you only return one field when there are multiple entries for each field? - sql

Question

I am trying to only return one email address for each employee. An Employee can be both an employee and a student. If you have both an employee and student email address then I only want to return the employee email address else if you only have student email address then return the student email address.
Here is the entire query:
select --spriden_pidm as pidm,
spriden_id as ban_id,
spriden_last_name as lastname,
spriden_first_name as firstname,
gmal.email,
phone_number.area || phone_number.phone as phone_number,
addr.permanent_address AS street,
addr.permanent_city AS city,
addr.permanent_state AS state,
addr.permanent_zip AS zip,
case
when nbrjobs_ecls_code in ('E1', 'E2', 'EN', 'F1', 'F2') and nbrjobs_ann_salary between 0 and 49999.99 then 'EHRA1'
when nbrjobs_ecls_code in ('E1', 'E2', 'EN', 'F1', 'F2') and nbrjobs_ann_salary between 50000 and 99999.99 then 'EHRA2'
when nbrjobs_ecls_code in ('E1', 'E2', 'EN', 'F1', 'F2') and nbrjobs_ann_salary between 100000 and 149999.99 then 'EHRA3'
when nbrjobs_ecls_code in ('E1', 'E2', 'EN', 'F1', 'F2') and nbrjobs_ann_salary >= 150000 then 'EHRA4'
when nbrjobs_ecls_code in ('SE', 'SN', 'LE') and nbrjobs_ann_salary between 0 and 49999.99 then 'SHRA1'
when nbrjobs_ecls_code in ('SE', 'SN', 'LE') and nbrjobs_ann_salary between 50000 and 99999.99 then 'SHRA2'
when nbrjobs_ecls_code in ('SE', 'SN', 'LE') and nbrjobs_ann_salary between 100000 and 149999.99 then 'SHRA3'
when nbrjobs_ecls_code in ('SE', 'SN', 'LE') and nbrjobs_ann_salary >= 150000 then 'SHRA4'
when nbrjobs_ecls_code in ('FA') then 'AF'
when nbrjobs_ecls_code in ('SH', 'SS', 'TS', 'WS') then 'M1'
else
null
end as empl_cat
from nbrjobs a,
spriden,
(select goremal_pidm as pidm,
goremal_email_address as email
from goremal
where goremal_emal_code in ('EMPL', 'STDN')
and goremal_status_ind = 'A') gmal,
(SELECT sprtele_pidm AS pidm,
sprtele_phone_area AS area,
sprtele_phone_number AS phone
FROM sprtele c
WHERE sprtele_tele_code = 'CA'
AND sprtele_primary_ind = 'Y'
AND sprtele_status_ind IS NULL
AND sprtele_seqno =
(SELECT MAX (sprtele_seqno)
FROM sprtele
WHERE sprtele_tele_code = 'CA'
AND sprtele_primary_ind = 'Y'
AND sprtele_status_ind IS NULL
AND sprtele_pidm = c.sprtele_pidm)) phone_number,
--spraddr
(SELECT spraddr_pidm AS pidm,
spraddr_street_line1 AS permanent_address,
spraddr_city AS permanent_city,
spraddr_stat_code AS permanent_state,
spraddr_zip AS permanent_zip
FROM spraddr b
WHERE spraddr_atyp_code = 'CA'
AND spraddr_status_ind IS NULL
AND spraddr_seqno =
(SELECT MAX (spraddr_seqno)
FROM spraddr
WHERE spraddr_atyp_code = 'CA'
AND spraddr_status_ind IS NULL
AND spraddr_pidm = b.spraddr_pidm)) addr
where a.nbrjobs_pidm = spriden_pidm
and a.nbrjobs_pidm = gmal.pidm(+)
and a.nbrjobs_pidm = phone_number.pidm(+)
and a.nbrjobs_pidm = addr.pidm(+)
and spriden_change_ind is null
and a.nbrjobs_sgrp_code = to_char(sysdate, 'YYYY')
and a.nbrjobs_effective_date = (select max(b.nbrjobs_effective_date)
from nbrjobs b
where b.nbrjobs_pidm = a.nbrjobs_pidm
and b.nbrjobs_posn = a.nbrjobs_posn
and b.nbrjobs_effective_date <= sysdate
--and b.nbrjobs_ecls_code in ('E1','E2','EN','F1','F2','SE','SN','LE')
and b.nbrjobs_ecls_code in ('E1','E2','EN','F1','F2','SE','SN','LE', 'RF', 'AF', 'FA', 'SH', 'SS', 'TS', 'WS')
and b.nbrjobs_sgrp_code = to_char(sysdate, 'YYYY'))
and a.nbrjobs_status <> 'T';`
and this is the part of the query I am trying to change to return the desired email address
(select goremal_pidm as pidm,
goremal_email_address as email
from goremal
where goremal_emal_code in ('EMPL', 'STDN')
and goremal_status_ind = 'A') gmal,

Answer 1

So the issue is that the query will return two email addresses if the employee is also a student? What you can do in this case is PIVOT the data, then use COALESCE() to get the student email where the employee email is NULL. The below query would replace the problematic subquery:
SELECT pidm, COALESCE(empl_email, stdn_email) AS email
FROM (
SELECT goremal_pidm AS pidm, goremal_email_address AS email, goremal_emal_code
FROM goremal
WHERE goremal_emal_code in ('EMPL', 'STDN')
AND goremal_status_ind = 'A'
) PIVOT (
MAX(email) FOR goremal_emal_code IN ('EMPL' AS empl_email, 'STDN' AS stdn_email)
)
EDIT: As an aside, you can use conditional aggregation instead of an explicit PIVOT (helpful if you're using Oracle 9i or lower):
SELECT pidm, COALESCE(empl_email, stdn_email) AS email FROM (
SELECT goremal_pidm AS pidm
, MAX(CASE WHEN goremal_emal_code = 'EMPL' THEN goremal_email_address END) AS empl_email
, MAX(CASE WHEN goremal_emal_code = 'STDN' THEN goremal_email_address END) AS stdn_email
FROM goremal
WHERE goremal_emal_code in ('EMPL', 'STDN')
AND goremal_status_ind = 'A'
GROUP BY goremal_pidm
)
Hope this helps.

Answer 2

Try using NVL2, as a example for your case -
NVL2(EMP_EMAIL_ADR, EMP_EMAIL_ADR, STDN_EMAIL_ADR)
This clause will return if the Employee email address is not null else it returns Student email address.
Hope this helps.