Hello I am fairly new to SQL and having spent much time over the manual I decided to ask for help. So here's my deal.
I've got a query with 5 tables that I join together
The problem is the table Threat_Map is a many to many mapping between the Map table and the Threat table. Eg) A map can have more than one threat and a threat can have more than one map. I know this is not the best way to have a database set up but its out of my hands as to changing the database. What I need help with is this.
My application checks as to whether a certain field in the Map table is expired or out of date (as in the query). If so it gets some required information from the other tables using those joins. However, I don't want to get information for the same Map.mapID that's expired twice. I don't really care which ThreatID I get from the Threat_Map table I just need to get one of them to meet the objects standards. However, so far this seemingly simple task has eluded me. I'd like to do this in SQL. Is there perhaps a way to do this. If not I guess I'll just take care of it in the application.
-Alex
I've got a query with 5 tables that I join together
Code:
SELECT * FROM Map
INNER JOIN ThreatCategory
INNER JOIN Threat ON
ThreatCategory.threatCategoryID = Threat.threatCategoryID
INNER JOIN Threat_Map
ON Threat.threatID = Threat_Map.threatID
ON Map.mapID = Threat_Map.mapID
LEFT JOIN person on map.contentPersonID = person.personID
WHERE (((DATEDIFF(dd, Map.dataAcquisitionDate, GETDATE()) > map.goodForDays) and (map.expired = '1'))
or (map.expired = '3'))
The problem is the table Threat_Map is a many to many mapping between the Map table and the Threat table. Eg) A map can have more than one threat and a threat can have more than one map. I know this is not the best way to have a database set up but its out of my hands as to changing the database. What I need help with is this.
My application checks as to whether a certain field in the Map table is expired or out of date (as in the query). If so it gets some required information from the other tables using those joins. However, I don't want to get information for the same Map.mapID that's expired twice. I don't really care which ThreatID I get from the Threat_Map table I just need to get one of them to meet the objects standards. However, so far this seemingly simple task has eluded me. I'd like to do this in SQL. Is there perhaps a way to do this. If not I guess I'll just take care of it in the application.
-Alex
