SQL Show table Query is for showing a list of tables from a database available on Database server. If you are using a GUI software to access your database (Query Analyser or PHPMYAdmin) then you will be able to see the list of avaialble tables by just using mouse. But if you are using a Shell or Cosole (DOS) then to see list of available tables, the show tables query is useful.
Show tables command is used for showing you all the tables inside a database. To use this command, first you need to go inside a databse by using use name-of-database command. Once you are inside a database, then you can easily use show tables command to see all the tables inside a database.
Its same like, when you want to read chapters from a book, first you need to open the book and then you can go through chapters