I have an issue with the below query:
select main.courseid
,main.coursename
,main.catid
,main.catname
,main.need_dte
from (
select t1.courseid
,t1.coursename
,t2.catid
,t2
,catname
,t2.need_dte
from t1
,t2
where t1.courseid = t2.courseid
and t1.coursename = t2.coursename
) main
left outer join (
select courseid
,coursename
,need_dte training_info
) ui on main.courseid = ui.courseid
and main.coursename = ui.coursename
and main.need_dte = ui.need_dte
I have the above scenario in which i am trying to do left outer join between the tables "main" and "training_info".
main table: a inner join between t1 and t2 to get the training and the category details.
training_info(ui): has training details without category details.
here i have few course details in "main" and "ui" tables in common. and i have few unique course records in "main" table not in "ui" table. so i am trying to extract both the unique and common records.
I am able to get the results for this join, but the issue is with the need_dte. the need_dte field is present in both tables.In the result if the records are from "main" table am able to get the need_dte field updated from the inner table t2. if the records are from "ui" table in the result, the need_dte is not being populated.
Is there any way using this join set up I need to get the need_dte for the result records from training_info table also if those records have a need_dte.
Thanks!
Is this what you want?
select t1.courseid, t1.coursename, t2.catid, t2.catname,
coalesce(ti.need_dte, t2.need_dte ) as need_dte
from t1 join
t2
on t1.courseid = t2.courseid and
t1.coursename = t2.coursename left outer join
training_info ti
on t1.courseid = ti.courseid and
t1.coursename = ti.coursename and
t2.need_dte = ti.need_dte;
I find your query with the nested subqueries, multiple levels of naming, and archaic join
syntax to be difficult to read. I think the above is what you are looking for. It returns need_dte
from training_info
, if present, and then from t2
.
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