My flange is mouted flush w/the cement floor.How do I raise it up to meet the sub floor 7/8" plus 1/4 " for the tile? Is there an adapter?

They make a extension in PVC and possibly for other flanges, or you can try a regular wax gasket with a repair wax ring with a rubber or plastic collar (repair flange) on top of the regular wax ring with the repair flange above it with the collar going through the bottom ring to keep the wax ring from blocking the toilet opening

To make a correction,where I said repair flange I meant repair wax ring

You can by toilet closet flange extender kit, see the image below, Thanks.

John

I got the "extended closet flange",which fit into the 3" pvc.I installed the subfloor,and mouted the flange to the subfloor.Problem solved. Thanks for the great answers.The guy at Home Depot, told me I had to dig up the cement,cut the 3"line,add a coupling w/a new elbow, and flange... What?

The guy at Home Depot, told me I had to dig up the cement,cut the 3"line,add a coupling w/a new elbow, and flange...
Which is why big box salesmen aren't out there doing plumbing.
Cheers, Tom