text: /*
  We've learned our first DDL command CREATE, 
  and now it's time to learn the second: ALTER
  
  We'll use ALTER TABLE command to add,delete or update something about our tables.
  Such as when we create our table we forgot to add a column, or we changed wrong datatype for a column
  we can use ALTER TABLE tbl_name to change it.
  
  There are lots of things we can do with ALTER but for now we'll just see the basic ones.
  
  ALTER TABLE tbl_name ADD column_name datatype;
  ALTER TABLE tbl_name DROP column_name;
  ALTER TABLE tbl_name ALTER COLUMN column_name TYPE datatype;
  
  Let's make examples to understand it clearly.
  */
  
  ALTER TABLE public."students" ADD student_phone_number char(11);
  
  ALTER TABLE public."students" DROP email;
  
  ALTER TABLE public."students" ALTER COLUMN first_name TYPE varchar(20);
  
  /*
  ADD adds a column 
  DROP drops/removes a column
  ALTER COLUMN column_name TYPE dtype changes the datatype of a column.
  */
  
  
  
  
  