TRY IT YOURSELF $7$

Continue your exploration of joins and set operators with these exercises:

$1.$ According to the census population estimates, which county had the greatest percentage loss of population between $2010$ and $2019?$ Try an internet

search to find out what happened. $($Hint: The decrease is related to a particular type of facility.$)$

Joining Tables in a Relational Database $115$

$2.$ Apply the concepts you learned about UNION to create query results that

merge queries of the census county population estimates for $2010$ and

$2019.$ Your results should include a column called year that specifies the

year of the estimate for each row in the results.

$3.$ Using the percentile$\_$cont$()$ function from Chapter $6,$ determine the

median of the percent change in estimated county population between

$2010$ and $2019$