Oracle SQL - select from view more rows than running select in the view - sql

Question

When I run this SQL, I get 116,463 rows.
select * from appsdisc.appsdisc_phones_gen_v
When I run the select that is in the view definition script, I get 11,702 rows.
I can't figure out why the result set is different.
The view script is as follows.
CREATE OR REPLACE FORCE VIEW APPSDISC.APPSDISC_PHONES_GEN_V
(PARTY_ID, CUSTOMER_ID, CUSTOMER_NUMBER, PHONE_NUMBER, PHONE_TYPE)
AS
SELECT party_id,
customer_id,
customer_number,
phone_number,
phone_type
FROM appsdisc_phones_v pv1
WHERE pv1.phone_type LIKE
DECODE (TRIM (SUBSTR (pv1.attribute14, 1, 4)),
'FR', 'FR T%',
'PHONE')
AND pv1.contact_point_id =
(SELECT MIN (pv2.contact_point_id)
FROM appsdisc_phones_v pv2
WHERE pv2.customer_id = pv1.customer_id
AND pv2.phone_type LIKE
DECODE (
TRIM (SUBSTR (pv1.attribute14, 1, 4)),
'FR', 'FR T%',
'PHONE'));

Answer 1

If you're running the view query exactly as it is, and you are not logged in as APPSDISC, you might be querying your own table (or view), since appsdisc_phones_v isn't prefixed by the schema in the view script. Hopefully this is a development environment and you have an old copy for a valid reason.
Here's a demo of the effect I think you're seeing. As one user (SOUSER1) I can create and populate a table with a view on top of it, and grant access to that view to a different user. Notice I don't need to grant access to the underlying table directly.
create table my_table (id number);
insert into my_table
select level as id from dual connect by level <= 1000;
commit;
create view souser1.my_view as select * from my_table;
grant select on souser1.my_view to souser2;
select count(*) from my_view;
COUNT(*)
----------
1000
select count(*) from my_table;
COUNT(*)
----------
1000
I didn't specify the schema in the select inside the view statement, so it's going to be the same as the view owner, which is SOUSER1 in this case.
Then as a second user (SOUSER2) I can create my own version of the table, with fewer rows. Querying the view still shows the row count from the SOUSER1 table, not my own.
create table my_table (id number);
insert into my_table
select level as id from dual connect by level <= 100;
commit;
select count(*) from souser1.my_view;
COUNT(*)
----------
1000
If I run the query from the original view I'm seeing my own copy of the table, which is smaller, because the table name isn't qualified with the schema name - hence it defaults to my own:
select count(*) from my_table;
COUNT(*)
----------
100
So seeing a different number of rows makes sense as long as there are two versions of the table and you haven't specified which you want to query.
And in my case, if I try to query the other schema's table directly I get an error, since I didn't grant any privileges on that:
select count(*) from souser1.my_table;
SQL Error: ORA-00942: table or view does not exist
00942. 00000 - "table or view does not exist"
But you'd see the same error querying my_table if you don't have your own copy, you don't set your current schema on login, and you don't have a synonym pointing to a table in some schema.

Answer 2

Gordon is right, the select should return the same results as the view. Issues such as running the query in different schema, databases, or over database links could explain what you are observing. You can see this by running the two SQL commands in the same database and schema below and comparing the values returned by both.
First, confirm the number of rows the view returns with the SQL:
SELECT COUNT(*) FROM APPSDISC.APPSDISC_PHONES_GEN_V;
Then confirm the number of rows the query for the view returns with the SQL:
WITH RESULTS AS (
SELECT party_id,
customer_id,
customer_number,
phone_number,
phone_type
FROM appsdisc_phones_v pv1
WHERE pv1.phone_type LIKE
DECODE (TRIM (SUBSTR (pv1.attribute14, 1, 4)),
'FR', 'FR T%',
'PHONE')
AND pv1.contact_point_id =
(SELECT MIN (pv2.contact_point_id)
FROM appsdisc_phones_v pv2
WHERE pv2.customer_id = pv1.customer_id
AND pv2.phone_type LIKE
DECODE (
TRIM (SUBSTR (pv1.attribute14, 1, 4)),
'FR', 'FR T%',
'PHONE')))
SELECT COUNT(*)
FROM RESULTS
/
Both queries should be returning the same values. If not then there is more to this issue than a query returning a different number of rows.