Disclosed herein are system, method, and computer program product embodiments for generating join histograms. An embodiment operates by a computer implemented method that includes determining, by at least one processor, a first interval associated with a first histogram of a first data structure and a first estimate frequency associated with the first interval. The method further includes determining, by the at least one processor, a second interval associated with a second histogram of a second data structure and a second estimate frequency associated with the second interval. The method further includes determining, by the at least one processor, a join interval based on the first and second intervals by calculating an intersection of the first and second intervals. The method further includes calculating, by the at least one processor, a join estimate frequency based on the first and second estimate frequencies.