Expand the length of the last$\_$name column to the sec$0612\_$employees table. Expand it to a

length of $50$ letters so people with hyphenated last names can be hired by the company.

$(6-13)$ Question $5$:

Delete the phone$\_$number column from a the sec$0613\_$employees table.

$(6-16)$ Question $6$:

Eliminate the duplicate rows from the sec$0616\_$duplicate$\_$rows table.

$(6-17)$ Question $7$:

Assign a number to each row of the sec$0617\_$duplicate$\_$rows table.