How to find difference between table with multiple conditions - sql

Question

I have exact two tables but some value differences. So I would like to find those differences with condition that if the column value has a difference of more than 10.
For example, all 9 columns have the same values in both tables, but the difference between the values column is 11, so this record is different. If the value difference is 9 so records are the same.
So I wrote this query to get differences:
select *
from test.test m
inner join test.test1 t
on
m.month_date = t.month_date and
m.level_1 = t.level_1 and
m.level_2 = t.level_2 and
m.level_3 = t.level_3 and
m.level_4 = t.level_4 and
m.level_header = t.level_header and
m.unit = t.unit and
m.model_type_id = t.model_type_id and
m.model_version_desc = t.model_version_desc
where m.month_date = '2022-11-01' and abs(m.value - t.value) > 10)
so this returns me all records that all column values are matched but did not pass the value difference condition.
Second, i have full outer join to get all differences
select *
from test.test m
full outer join test.test1 t
on
m.month_date = t.month_date and
m.level_1 = t.level_1 and
m.level_2 = t.level_2 and
m.level_3 = t.level_3 and
m.level_4 = t.level_4 and
m.level_header = t.level_header and
m.unit = t.unit and
m.model_type_id = t.model_type_id and
m.model_version_desc = t.model_version_desc
where m.month_date is null or t.month_date is null and m.month_date = '2022-11-01'
How can I combine the results of these two queries without UNION? I want to have only one query (sub query is acceptable)

Answer 1

Assuming that for a given day, you need to find
rows that match between the tables but exceed the value difference threshold
AND
rows present in either left or right table, that don't have a corresponding row in the other table
select *
from test.test m
full outer join test.test1 t
using (
month_date,
level_1,
level_2,
level_3,
level_4,
level_header,
unit,
model_type_id,
model_version_desc )
where (m.month_date is null
or t.month_date is null
and m.month_date = '2022-11-01' )
or (m.month_date = '2022-11-01' and abs(m.value - t.value) > 10);
Online demo
Since the columns used to join the tables have the same names, you can shorten their list by swapping out the lengthy table1.column1=table2.column1 and... list of pairs for a single USING (month_date,level_1,level_2,level_3,...) (doc). As a bonus, it will avoid listing the matching columns twice in your output, once for the left table, once for the right table.
select *
from (select 1,2,3) as t1(a,b,c)
full outer join
(select 1,2,3) as t2(a,b,c)
on t1.a=t2.a
and t1.b=t2.b
and t1.c=t2.c;
-- a | b | c | a | b | c
-----+---+---+---+---+---
-- 1 | 2 | 3 | 1 | 2 | 3
select *
from (select 1,2,3) as t1(a,b,c)
full outer join
(select 1,2,3) as t2(a,b,c)
using(a,b,c);
-- a | b | c
-----+---+---
-- 1 | 2 | 3

Answer 2

In your first query, you can replace the null values for a specific number. Something like this:
where m.month_date = '2022-11-01' and abs(ISNULL(m.value,-99) - ISNULL(t.value,-99)) > 10)
The above will replace the nulls for -99 (choose an appropriate value for your data), so if you have that m.value is 10 and t.value is null, then should be returned in your first query.