David Gagnon <dgagnon@xxxxxxxxxx> writes: > update test set id=test2.id from test2 where id=test2.id; > > ERROR: column reference "id" is ambiguous It's complaining about the second use of "id", which could mean either "test2.id" (which would be a self-join) or "test.id" (which is what you want). -Doug ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match