left outer join doesnt return all rows on left table - sql

Question

set #fuel_type='hsd';
select
ro.ro_id,
(case
when if(#fuel_type='ms',r.ms_field_input_id,r.hsd_field_input_id)= 0
then if(#fuel_type='ms',concat(r.remark_ms,r.remark_branded),r.remark_hsd)
else
f.field_name
end )
from
retail_outlets ro left join
volume_trackers r on ro.ro_id=r.ro_id,
field_inputs_master f
where
if(#fuel_type='ms',r.ms_field_input_id = f.field_id,r.hsd_field_input_id=f.field_id)
and ro.pricing_module=1 and if(#fuel_type='ms',ro.ms,ro.hsd)=1 and r.date_inserted='2017-02-06'
;
I need to show all the ro_id in the retail_outlets table but only the ro_id that match with the volume trackers table are displayes

Answer 1

Not positive but I think this is what you're after.
changes are the following:
removed , notation and inject a left join
moved the r.date_inserted to the join criteria.
moved where clause for , join to new left join and altered to case statement as to why I used a left join... Since we tie back to R which is already a left join it made sense to me to continue with left joins...
removed some unneeded ()'s
Assumptions r.date_inserted is a varchar2 data type or '2017-02-06' is implicitly being cast correctly.
.
SET #fuel_type='hsd';
SELECT
ro.ro_id ,
CASE
WHEN IF(#fuel_type='ms',r.ms_field_input_id,r.hsd_field_input_id)= 0
THEN IF(#fuel_type='ms',concat(r.remark_ms,r.remark_branded),r.remark_hsd)
ELSE f.field_name
END
FROM retail_outlets ro
LEFT JOIN volume_trackers r
ON ro.ro_id = r.ro_id
AND r.date_inserted = '2017-02-06'
LEFT JOIN field_inputs_master f
ON f.field_id = CASE WHEN #fuel_type='ms'
THEN r.ms_field_input_id
ELSE r.hsd_field_input_id
END
WHERE ro.pricing_module=1
AND IF(#fuel_type ='ms',ro.ms,ro.hsd)=1;