Dynamic Query for Retriving the translated column value in SQL - sql

Question

I have a table_lookup. This is the master table which has all the lookup codes like
LOOKUP_TYPE LOOKUP_CODE MEANING ENABLED_FLAG
EMP_CAT 3 Hourly with fixed hours per week Y
EMP_CAT 4 Hourly Y
EMP_CAT CAS Casual Y
EMP_CAT FR Full-time regular Y
EMP_CAT FR_01 Full-time Y
ABSENCE_CATEGORY DLHM Leave Y
ABSENCE_CATEGORY DLHNM Leave on the death of a husband Y
ABSENCE_CATEGORY DLR Leave on the death of a relative Y
ABSENCE_CATEGORY GB_ADO Adoption Y
ABSENCE_CATEGORY GB_PAT_ADO Paternity adoption Y
NATIONALITY PY Paraguayan Y
NATIONALITY QA Qatari Y
NATIONALITY RO Romanian Y
NATIONALITY RS Serbian
This table is referenced in different tables like
table_assignment
emp no. name Employee category active/inactive
1 divya 3 A
2 abc FR A
3 XYZ 4 I
4 aMY 100 A
Table table_nationality
Emp no. nationality
1 QA
2 RS
4 RO
That is the lookup_code f is translated in the table_Assignment employee_category column and nationality column in table_nationality.
I have a query like:
select emp_no.,
name,
employee_category
from table_assignment lookup_assignmen,
table_lookup lookup_stg
where lookup_stg.lookup_type = 'EMP_CAT'
AND LOOKUP_STG.LOOKUP_CODE = lookup_assignmen.employee_category;
SIMILARLY for table_nationality something like:
select emp_no.,
nationality
from TABLE_NATIONALITY lookup_NATIONALITY,
table_lookup lookup_stg
where lookup_stg.lookup_type = 'NATIONALITY'
AND LOOKUP_STG.LOOKUP_CODE = lookup_NATIONALITY.employee_category;
Now I want a dynamic query which detects if in say for example table_assignment there is any employee category which is not there in the table_lookup.
For example : In the table_assignment there is a value 100 given in the employee category column this is not there in the table_lookup.
Such values should be retrieved in a query but the query should be dynamic such that it should retrieve all the invalid lookup values in table_Assignment, table_nationality or any other
tables. I can input the lookup_type and table name in the query and the invalid values should be retrieved.
How do I change my static query to dynamic?

Answer 1

you can union all the invalid codes and avoid dynamic sql.
select *
from (
select emp_no as entity_id, 'emp_cat' as lookup_type, eployee_category as invalid_lookup_code
from table_assignment e
left join table_lookup r
on e.employee_category = r.lookup_code
and r.lookup_type = 'emp_cat'
where r.lookup_type is null
union all
select emp_no as entity_id, 'nationality' as lookup_type, nationality as invalid_lookup_code
from table_nationality e
left join table_lookup r
on e.employee_category = r.lookup_code
and r.lookup_type = 'nationality'
where r.lookup_type is null
) as t
where t.lookup_type = 'nationality'

Answer 2

You can run dynamic SQL inside SQL with a package that combines Oracle Data Cartridge with the ANY types. The code below uses my open source version of this idea.
Even using pre-built PL/SQL, this will still be a difficult task since building queries in queries is confusing. And it's not clear how the tables are mapped together, it looks like there are no foreign keys or standard names. I assume there's a mapping table somewhere, or one can be created. For the demo, I created this:
create table lookup_map(
table_name varchar2(30),
column_name varchar2(30),
lookup_type varchar2(100)
);
insert into lookup_map
select 'TABLE_ASSIGNMENT', 'EMPLOYEE_CATEGORY', 'EMP_CAT' from dual union all
select 'TABLE_NATIONALITY', 'NATIONALITY', 'NATIONALITY' from dual;
commit;
This code will build and run dynamic queries for each table, and will UNION ALL the results.
select * from table(method4.dynamic_query(
q'[
select replace(replace(replace(q'!
select '#TABLE_NAME#' table_name, emp_no, #COLUMN_NAME#
from #TABLE_NAME#
left join table_lookup
on #TABLE_NAME#.#COLUMN_NAME# = table_lookup.lookup_code
and table_lookup.lookup_type = '#LOOKUP_TYPE#'
where table_lookup.lookup_code is null
!',
'#TABLE_NAME#', table_name),
'#COLUMN_NAME#', column_name),
'#LOOKUP_TYPE#', lookup_type) v_sql
from lookup_map
]'
));
TABLE_NAME EMP_NO EMPLOYEE_CATEGORY
---------- ------ -----------------
TABLE_ASSIGNMENT 4 100
To avoid quotation-mark-hell it's best to use the alternative quoting mechanism (q') and REPLACE. The quotation marks look unmatched in the Stackoverflow syntax highlighter but it should look better in an Oracle IDE.
This is overkill for this exact query. But it gives you plenty of room to grow. You can change the queries and make them even more dynamic without any additional PL/SQL code.