The main difference between all the Total column parameters (shown in Table 6 in ERA5 documentation) and the Total precipitation is that the firsts are instantaneous parameters in a column extending from the surface of the Earth to the top of the atmosphere. However, Total precipitation is an accumulated parameter over a particular time period which depends on the data extracted that falls to the Earth's surface.
All total column parameters are in kg m-2, instead Total precipitation is in m.
More information on all ECMWF parameters is available from the ECMWF parameter database.