I dont think this is possible via database however if you want to check for a quest, if a boss has been killed then you must do this:
In the quest, must save his name by using !addnamelist quest.txt, so that the other script will know, you have applied for this quest. Then you set the boss in mapquest, which directs it to specific script you have made once the monster have died. In mapquest it should look like this:
D1506 [0] 0 [MonDie] Tadanga * [Mapquest_def\quest1] [@Main]
So this takes you to the new script once the monster have been killed, in that scirpt you may put in:
[@main]
#IF
checknamelist quest.txt
#ACT
addnamelist quest1Finish.txt
So nice and easy, then you add an extension to your ORGINAL quest, so that it checks if the players name is in quest1finish.txt, if it is, it means he killed the boss, if it isnt there, then it means he did not killed the boss.
Hope you understand it, but in feature write in more detail and specificly whats the problem otherwise no one will answere, i looked at ur first post and its like 10 days old and though **** it, if i think what he means, then might as well try explaining.
BTW: IM NOT SURE IF ITS !ADDNAMELIST OR ADDNAMELIST, CORRECT ME GUYS.