Insread of select * why can't we use show command, it will show whole table?

Answer 1

ohk that mean show command only give name
while* gives whole content thanks!

Answer 2

Do you mean "show tables..."? If so, this will only print the names of the tables that (eventually) match a name pattern, whereas "select * from..." will show the actual content (i.e. the records therein) of a table.