declaring pl sql variable using query then using in subsequent query - oracle

Question

I’ve read some on declaring and using variables in PL/SQL. and I’ve only done so in other versions (TSQL) or code languages.
Below is what I’m trying to do, which is
to declare a variable
assign a value to that variable via query
use the subsequent result from #2
in another query.
I’ve tried other methods listed on the Internet but nothing I do seems to work when calling the variable in the final query.
The declaration and into statements work but the last select query does not.
declare
Degr_term varchar2(20);
begin
select max(z.term)
INTO degr_term
from dwh.rpt_ersd_vw d
join dwh.dim_ers_term_vw z
on d.DIM_DEGR_ERS_TERM_SKEY = z.dim_ers_term_skey;
select * from ir_wip.stem_enr s where s.min_deg_term = degr_term;
end;

Answer 1

Just like you selected INTO from the 1st select statement, you have to do it in the 2nd as well. It means that you'll have to declare a variable which will hold its contents.
Presuming - maybe not correctly - that 2nd select returns only one row - you could
SQL> declare
2 degr_term varchar2(20);
3 l_stem stem_enr%rowtype; --> this
4 begin
5 select max(z.term)
6 into degr_term
7 from rpt_ersd_vw d
8 join dim_ers_term_vw z
9 on d.DIM_DEGR_ERS_TERM_SKEY = z.dim_ers_term_skey;
10
11 select *
12 into l_stem --> this
13 from stem_enr s
14 where s.min_deg_term = degr_term;
15 end;
16 /
PL/SQL procedure successfully completed.
SQL>
(I removed schema names as I don't have them and didn't feel like creating ones.)
If the 2nd query returns more than a single row, then you'd e.g.
SQL> declare
2 degr_term varchar2(20);
3 type l_stem_typ is table of stem_enr%rowtype;
4 l_stem_tab l_stem_typ;
5 begin
6 select max(z.term)
7 into degr_term
8 from rpt_ersd_vw d
9 join dim_ers_term_vw z
10 on d.DIM_DEGR_ERS_TERM_SKEY = z.dim_ers_term_skey;
11
12 select *
13 bulk collect
14 into l_stem_tab
15 from stem_enr s
16 where s.min_deg_term = degr_term;
17 end;
18 /
PL/SQL procedure successfully completed.
SQL>
[EDIT: How to output the result? Using a loop]
Presume that table looks like this (I don't know really, you never posted any sample data):
SQL> select * from stem_enr;
MIN_DEG_TERM NAME SURN
------------ ------ ----
1 Little Foot
1 Big Foot
Then you'd (simplified example; I didn't feel like creating other tables as well):
SQL> declare
2 type l_stem_typ is table of stem_enr%rowtype;
3 l_stem_tab l_stem_typ;
4 begin
5 select *
6 bulk collect
7 into l_stem_tab
8 from stem_enr s
9 where s.min_deg_term = 1;
10
11 for i in 1 .. l_stem_tab.count loop
12 dbms_output.put_line(l_stem_tab(i).name ||' '|| l_stem_tab(i).surname);
13 end loop;
14 end;
15 /
Little Foot
Big Foot
PL/SQL procedure successfully completed.
SQL>