Convert INNER JOIN to LEFT JOIN - Sql - sql

Question

i have a query which returns ~ 97k records because i am using an inner join. Now i want to use left join to show also the null records on the right table(should be about 300k records). This is the actual query(INNER JOIN):
select artnr as "Article number", ardbez1 as "Article description ", arpadrnr as "Supplier code", cd.ADPPHYSLAND as "Country of this supplier code", p.adrnr as "Parent supplier code", p.adrkname as "Name of parent", pd.ADPPHYSLAND as "Country of parent ", arppreis as "Price", arpwae as "Unit", arzwert as "COO", atatarnr as "HS Code"
from mic_ccs_artikel, mic_ccs_artikeldetail, mic_ccs_artikelpreis, mic_dna_adressen c, mic_dna_adrdetail cd, mic_dna_adressen p, mic_dna_adrrelation, mic_dna_adrdetail pd, mic_ccs_artikelzoll, mic_ccs_artikeltarif
where artsid = ardartsid
and arddatstart <= sysdate
and nvl(arddatend, '01.01.4000') >= sysdate
and artsid = arpartsid
and ARPPREISART = 'VP'
and arpdatstart <= sysdate
and nvl(arpdatend, '01.01.4000') >= sysdate
and c.adrsid = cd.adpadrsid
and arpadrnr = c.adrnr
and cd.adpdatvon <= sysdate
and nvl(cd.adpdatbis, '01.01.4000') >= sysdate
and c.adrmandant = 'S1'
and c.adrwerk = 'V1'
and p.adrmandant = 'S1'
and p.adrwerk = 'V1'
and p.adrsid = arlrelsid1
and c.adrsid = arlrelsid2
and p.adrsid = pd.adpadrsid
and pd.adpdatvon <= sysdate
and nvl(pd.adpdatbis, '01.01.4000') >= sysdate
and artsid = arzartsid
and arztyp = 'URLD'
and arzadrnr = c.adrnr
and arzdatstart <= sysdate
and nvl(arzdatend, '01.01.4000') >= sysdate
and artsid = ataartsid
and ATAREGION = 'SE'
and atatarart='EXPORT'
and atadatstart <= sysdate
and nvl(atadatend, '01.01.4000') >= sysdate
;
Then i tried to "convert" it to LEFT JOIN, but it's always showing the same result:
select artnr as "Article number", ardbez1 as "Article description ", arpadrnr as "Supplier code", cd.ADPPHYSLAND as "Country of this supplier code", p.adrnr as "Parent supplier code", p.adrkname as "Name of parent", pd.ADPPHYSLAND as "Country of parent ", arppreis as "Price", arpwae as "Unit", arzwert as "COO", atatarnr as "HS Code"
from mic_ccs_artikel, mic_ccs_artikeldetail, mic_ccs_artikelpreis, mic_dna_adressen c, mic_dna_adrdetail cd, mic_dna_adressen p, mic_dna_adrrelation, mic_dna_adrdetail pd, mic_ccs_artikelzoll, mic_ccs_artikeltarif
where artsid = ardartsid(+)
and arddatstart <= sysdate
and nvl(arddatend, '01.01.4000') >= sysdate
and artsid = arpartsid(+)
and ARPPREISART = 'VP'
and arpdatstart <= sysdate
and nvl(arpdatend, '01.01.4000') >= sysdate
and c.adrsid = cd.adpadrsid(+)
and arpadrnr = c.adrnr
and cd.adpdatvon <= sysdate
and nvl(cd.adpdatbis, '01.01.4000') >= sysdate
and c.adrmandant = 'S1'
and c.adrwerk = 'V1'
and p.adrmandant = 'S1'
and p.adrwerk = 'V1'
and p.adrsid = arlrelsid1(+)
and c.adrsid = arlrelsid2
and p.adrsid = pd.adpadrsid
and pd.adpdatvon <= sysdate
and nvl(pd.adpdatbis, '01.01.4000') >= sysdate
and artsid = arzartsid(+)
and arztyp = 'URLD'
and arzadrnr = c.adrnr
and arzdatstart <= sysdate
and nvl(arzdatend, '01.01.4000') >= sysdate
and artsid = ataartsid(+)
and ATAREGION = 'SE'
and atatarart='EXPORT'
and atadatstart <= sysdate
and nvl(atadatend, '01.01.4000') >= sysdate
;
Why is it always showing the same result?

Answer 1

Echoing the sentiments in the comments, using a left join and a where clause can result in some unexpected behavior. See my answer here for more details as to why that happens. Basically, you should switch to using ANSI syntax and alias your tables. In your case, that would look something like
select * -- select whichever fields you want here
from mic_ccs_artikel a -- only one table in the from clause
left join mic_ccs_artikeldetail b on b.someID = a.someID -- join conditions here
left join mic_ccs_artikelpreis c
on c.someID = a.someID -- join conidition
and c.someField = 'Some Property' -- filtering here
...
The secondary join conditions removes the risk of throwing out those records in the where clause. Again, see my other answer for more details on that.