Excluding records from table based on rules from another table - sql

Question

I'm using Oracle SQL and I have a product table with diffrent attributes and sales volume for each product and another table with certain exclusion rules for different level of aggregation. Let's look at the example:
Here is our main table with sales data on which we want to perform some calculations:
And the other table contains diffrent rules which are supposed to exclude certain rows from table above:
When there is an "x", this column shouldn't be considered so our rules are:
1. exclude all rows with ATTR_3 = 'no'
2. exlcude all rows with ATTR_1 = 'Europe' and ATTR_2 = 'snacks' and ATTR_3 = 'no'
3. exlcude all rows with ATTR_1 = 'Africa'
And based on that our final output should be like that:
How this could be achived in SQL? I was thinking about join but I have no idea how to handle different levels of aggregation for exclusions.

Answer 1

I think your expected output is wrong. None of the rules excludes the 2nd row (Europe - snacks - yes).
SQL> with
2 -- sample data
3 test (product_id, attr_1, attr_2, attr_3) as
4 (select 81928 , 'Europe', 'beverages', 'yes' from dual union all
5 select 16534 , 'Europe', 'snacks' , 'yes' from dual union all
6 select 56468 , 'USA' , 'snacks' , 'no' from dual union all
7 select 129921, 'Africa', 'drinks' , 'yes' from dual union all
8 select 123021, 'Africa', 'snacks' , 'yes' from dual union all
9 select 165132, 'USA' , 'drinks' , 'yes' from dual
10 ),
11 rules (attr_1, attr_2, attr_3) as
12 (select 'x' , 'x' , 'no' from dual union all
13 select 'Europe', 'snacks', 'no' from dual union all
14 select 'Africa', 'x' , 'x' from dual
15 )
16 -- query you need
17 select t.*
18 from test t
19 where (t.attr_1, t.attr_2, t.attr_3) not in
20 (select
21 decode(r.attr_1, 'x', t.attr_1, r.attr_1),
22 decode(r.attr_2, 'x', t.attr_2, r.attr_2),
23 decode(r.attr_3, 'x', t.attr_3, r.attr_3)
24 from rules r
25 );
PRODUCT_ID ATTR_1 ATTR_2 ATT
---------- ------ --------- ---
81928 Europe beverages yes
16534 Europe snacks yes
165132 USA drinks yes
SQL>

Answer 2

You can use the join using CASE .. WHEN statement as follows:
SELECT P.*
FROM PRODUCT P
JOIN RULESS R ON
(R.ATTR_1 ='X' OR P.ATTR_1 <> R.ATTR_1)
AND (R.ATTR_2 ='X' OR P.ATTR_2 <> R.ATTR_2)
AND (R.ATTR_3 ='X' OR P.ATTR_3 <> R.ATTR_3)

Answer 3

You can use NOT EXISTS
SELECT *
FROM sales s
WHERE NOT EXISTS (
SELECT 0
FROM attributes a
WHERE ( ( a.attr_1 = s.attr_1 AND a.attr_1 IS NOT NULL )
OR a.attr_1 IS NULL )
AND ( ( a.attr_2 = s.attr_2 AND a.attr_2 IS NOT NULL )
OR a.attr_2 IS NULL )
AND ( ( a.attr_3 = s.attr_3 AND a.attr_3 IS NOT NULL )
OR a.attr_3 IS NULL )
)
where I considered the x values within the attributes table as NULL. If you really have x characters, then you can use :
SELECT *
FROM sales s
WHERE NOT EXISTS (
SELECT 0
FROM attributes a
WHERE ( ( NVL(a.attr_1,'x') = s.attr_1 AND NVL(a.attr_1,'x')!='x' )
OR NVL(a.attr_1,'x')='x' )
AND ( ( NVL(a.attr_2,'x') = s.attr_2 AND NVL(a.attr_2,'x')!='x' )
OR NVL(a.attr_2,'x')='x' )
AND ( ( NVL(a.attr_3,'x') = s.attr_3 AND NVL(a.attr_3,'x')!='x' )
OR NVL(a.attr_3,'x')='x' )
)
instead.
Demo

Answer 4

I would do this with three different not exists:
select p.*
from product p
where not exists (select 1
from rules r
where r.attr_1 = p.attr_1 and r.attr_1 <> 'x'
) and
not exists (select 1
from rules r
where r.attr_2 = p.attr_2 and r.attr_2 <> 'x'
) and
not exists (select 1
from rules r
where r.attr_3 = p.attr_3 and r.attr_3 <> 'x'
) ;
In particular, this can take advantage of indexes on (attr_1), (attri_2) and (attr_3) -- something that is quite handy if you have a moderate number of rules.