Oracle SQL Join query results - sql

Question

I have the following two tables
Table 1: SOURCE_SYSTEM
ID CODE Source ID Source Name
123 111 Monster Dice.com
456 111 Dice ABC COMPANY
456 888 Ticv A2 systems
4566 999 MOnster hgtt solutions
789 222 Monster ABC COMPANY
985 222 Dice Dice.com
Table 2: TARGET_SYSTEM
RECORDID AI CL ID Source Name Op Code
123 111 Dice.com Secondary
456 111 ABC COMPANY Primary
789 222 ABC COMPANY Secondary
985 222 Dice.com Primary
We have a process which runs gets the data from source table and loads into target table. But in here the process has a rule saying the primary row in Target should has the Source Name from Source table where Source ID = ‘Monster’.
Here the following entry in Target is correct
RECORDID AI CL ID Source Name Op Code
123 111 Dice.com Secondary
456 111 ABC COMPANY Primary
But the following is wrong, has Primary Source name is Dice.com which should be ABC COMPANY.
RECORDID AI CL ID Source Name Op Code
789 222 ABC COMPANY Secondary
985 222 Dice.com Primary
So I need a query which can identify all the rows in Target which the same issue.

Answer 1

Why are the two rows for AI_CL_ID = 111 correct? They are wrong according to your specification, because recorded = 123 corresponds to 'Monster' but it has 'Secondary' in your target_system table.
To find all the rows in the target_system table with the wrong op_code you can use the following query. Assumptions: The pair (id, code) is unique target_system; there are no NULLs in any column; the source_name in target_system is always correct (it matches the source_name in source_system when matched by id and code); the marker 'Primary' is special, but there may be other markers besides 'Secondary'.
The solution does not include the rows from "with" to the closing " ) " after the definition of target_system; the WITH clause is used to generate test data within the query itself, but in real life you should simply start with select t.id, ... and hit your base tables or views.
with
source_system ( id, code, source_id, source_name) as (
select 123, 111, 'Monster', 'Dice.com' from dual union all
select 456, 111, 'Dice' , 'ABC COMPANY' from dual union all
select 456, 888, 'Ticv' , 'A2 systems' from dual union all
select 4566, 999, 'MOnster', 'hgtt solutions' from dual union all
select 789, 222, 'Monster', 'ABC COMPANY' from dual union all
select 985, 222, 'Dice' , 'Dice.com' from dual
),
target_system ( recordid, ai_cl_id, source_name, op_code ) AS (
select 123, 111, 'Dice.com' , 'Secondary' from dual union all
select 456, 111, 'ABC COMPANY', 'Primary' from dual union all
select 789, 222, 'ABC COMPANY', 'Secondary' from dual union all
select 985, 222, 'Dice.com' , 'Primary' from dual
)
select t.recordid, t.ai_cl_id, t.source_name, t.op_code
from target_system t inner join source_system s
on t.recordid = s.id and t.ai_cl_id = s.code
where ( s.source_id = 'Monster' and t.op_code != 'Primary' )
or
( s.source_id != 'Monster' and t.op_code = 'Primary' )
order by ai_cl_id, recordid
;
Output (with your inputs; the output is different from that in your post since what you have in your post is wrong, as I explained).
RECORDID AI_CL_ID SOURCE_NAME OP_CODE
---------- ---------- ----------- ---------
123 111 Dice.com Secondary
456 111 ABC COMPANY Primary
789 222 ABC COMPANY Secondary
985 222 Dice.com Primary