I have a field that is populated with a series of criteria in a specific format:
CRITERIA
$1 = True
$2 > $3
The criteria information is stored in a table
CRIT_ID CRIT_DESCRIPTION
1 Example 1
2 Example 2
3 Example 3
The final output should look like this
CRITERIA
Example 1 = True
Example 2 > Example 3
Can anyone suggest how best to accomplish this? I have tried REPLACE and dabbled with REGEXP_REPLACE so far...
Perhaps not the most efficient, but it works recursively (that is, if the crit_description itself contains "placeholders", those are expanded as well. (A first solution, simpler than what's shown below, didn't do this recursive step.) See the third sample input which I added. I will post again later if I can clean it up some more.
NOTE: This assumes all "placeholders" are actually found in the criteria_info table; I didn't test what happens if they are not found. OP to state the requirement.
with
inputs ( criteria ) as (
select '$1 = True' from dual union all
select '$2 > $3' from dual union all
select '$1 = $4' from dual
),
criteria_info ( crit_id, crit_description ) as (
select 1, 'Example 1' from dual union all
select 2, 'Example 2' from dual union all
select 3, 'Example 3' from dual union all
select 4, '$2 + $3' from dual
),
rec ( criteria, new_str ) as (
select criteria, criteria
from inputs
union all
select r.criteria,
regexp_replace(r.new_str, '\$\d+', c.crit_description, 1, 1)
from rec r inner join criteria_info c
on to_number(regexp_substr(r.new_str, '\$(\d+)', 1, 1, null, 1)) = c.crit_id
where regexp_substr(r.new_str, '\$\d+') is not null
)
select criteria, new_str
from rec
where regexp_substr(new_str, '\$\d+') is null
;
CRITERIA NEW_STR
--------- ------------------------------------
$1 = True Example 1 = True
$2 > $3 Example 2 > Example 3
$1 = $4 Example 1 = Example 2 + Example 3
3 rows selected.
In the following query I'm using the first SPACE as a separator between the id and the equation (and assuming that the id always start on the second char).
SELECT B.CRIT_DESCRIPTION || SUBSTR(A.CRITERIA, INSTR(A.CRITERIA, ' '))
FROM A, B
WHERE TO_NUMBER(SUBSTR(A.CRITERIA, 2, INSTR(A.CRITERIA, ' ') - 2)) = B.CRIT_ID
SUBSTR.