Summary

Currently, Jira does not store the project creation date outside of the audit logs which are cleaned periodically. With that, the creation date is only stored in the Jira Database when advanced auditing is set (if available), and for many cases the information may not be retrieved from there.

Solution

First, check if the information is stored in the database with:

SELECT 
	"ENTITY_TIMESTAMP" as timestamp, 
	"PRIMARY_RESOURCE_ID" as project_id, 
	"SECONDARY_RESOURCE_ID" as username, 
	"RESOURCES" as details 
FROM public."AO_C77861_AUDIT_ENTITY"
WHERE "ACTION_T_KEY" = 'jira.auditing.project.created'
ORDER BY "ID" ASC LIMIT 100;

If not present, the closest date we can get as a workaround for this is to retrieve the date of the first issue created on the projects.

This workaround is only applicable if the project is not empty (only if it contains issues).

Run the query below in Jira's database to retrieve all project keys and their first issue-created date.

select P.pkey, min(I.created) 
from jiraissue I
join project P on P.id = I.project
group by P.pkey;

You can add the number of issues on each project by adding count(I.ID) to your select statement:

select P.pkey, min(I.created), count(I.ID)
from jiraissue I
join project P on P.id = I.project
group by P.pkey;