Question

I have two tables as: table1 with fields c1 and dt(nullable); table2 with fields start_dt, end_dt and wk_id. Now I need to perform left outer join between the table1 and table2 to take wk_id such that dt falls between start_dt and end_dt. I applied following condition but some wk_id which shouldn’t be NULL are pulled NULL and some rows get repeated.

where nvl(t1.dt,'x') between nvl(t2.start_dt(+), 'x') and nvl(t2.end_dt(+), 'x');

What is wrong with the condition?

Answer 1

select *
from table1 t1
left join table2 t2
    on t1.dt between t2.start_dt and t2.end_dt

I recommend you try the new ANSI join syntax.

Also, are you just using 'x' as an example? Or are the dt columns really stored as strings?