We present a database of the absolute magnitudes of asteroids named the Kharkiv Asteroid Absolute Magnitude Database (KhAAMD). The database includes a homogeneous set of the absolute magnitudes for about 400 asteroids in the new HG1G2 magnitude system. We performed a comparative analysis of the asteroid absolute magnitudes between the Kharkiv database and other main magnitude databases (MPC, Pan-STARRS, ATLAS, PTF, and Gaia). We show that the PanSTARRS absolute magnitude dataset has no systematic deviations and is the most suitable for the determination of diameters or albedos of asteroids. For the MPC dataset, there is a linear trend to overestimate the absolute magnitudes of bright objects and underestimate the magnitudes of faint asteroids. The ATLAS dataset has both a systematic overestimation of asteroid magnitudes and a linear trend. We propose the equations, which can be used to correct for systematic errors in the MPC and the ATLAS magnitude datasets. There are possible systematic deviations of about 0.1mag for Gaia and PTF databases but we have insufficient data overlapping with our data for a definitive analysis.