Given the following relational database schema: Users$($uid$,$ name, school, year, age$)$

Friends$($uid$1,$ uid$2)$

Foreign key$($uid$1)$ references Users$($uid$)$ Foreign key$($uid$2)$ references Users$($uid$)$

Posts$($pid$,$ uid, text, datetime, rating$)$

Foreign key$($uid$)$ references Users$($uid$)$

Likes$($uid$,$ pid, datetime$)$

Foreign key$($uid$)$ references Users$($uid$)$ Foreign key$($pid$)$ references Posts$($pid$)$

Write SQL commands to achieve each of the following requests $[5$ points for each$]$:

$1)$ Retrieve each post text and the name of the user who has posted it$.$

$2)$ Retrieve the text of each post that has been posted by any person who is enrolled at UTD $($school$).$

$3)$ Retrieve the names of all the friends of the user $$John Smith$.$

$4)$ Retrieve the name of each user if he$/$she has posted any text that talks about $$UTD$.$

$5)$ Retrieve the name of user who does not have any post.

$6)$ Retrieve the name of each user and the number of friends he$/$she has.

$7)$ Retrieve the name$($s$)$ of the user$($s$)$ who has the maximum number of posts.

$8)$ Remove every fact that indicates that the user with the name $$John Smith$$ likes posts that were posted by the user whose name is $$Tom Harper$.$

$9)$ Increase the rating by $1$ for every post that has been posted by any user whose age is more than $80.$

$10)$ Prevent any user of age below $12$ from posting any text.