SQL Exercise: Find nurses who have ever been on call for room 122

SQL hospital Database: Exercise-35 with Solution

35. From the following table, write a SQL query to find out, which nurses have been on call for room 122 in the past. Return name of the nurses.

Sample table: nurse

Sample table: on_call

Sample table: room

Sample Solution:

SELECT n.name
FROM nurse n
WHERE employeeid IN
    ( SELECT oc.nurse
     FROM on_call oc,
          room r
     WHERE oc.blockfloor = r.blockfloor
       AND oc.blockcode = r.blockcode
       AND r.roomnumber = 122 );

Sample Output:

 Laverne Roberts
 Paul Flowers
(2 rows)	


The said query in SQL that selects the name of the nurse who is on-call for the same block and floor as room number 122.

In the subquery the nurse ID from the 'on_call' table, which stores information about nurses who are on call. A join builds with the 'room' table and 'on_call' table, to match the block and floor of the room number 122 with the corresponding block and floor of the nurse's on-call shift.

The outer query then selects the name of the nurse using the nurse's employee ID, which is found in the 'nurse' table.

The WHERE clause filters the nurse records based on whether their employee ID is in the list of nurse IDs returned by the subquery.

Practice Online

E R Diagram of Hospital Database:

E R Diagram: SQL Hospital Database.

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous SQL Exercise: Medical procedures done after certification expired.
Next SQL Exercise: Patients who have been prescribed some medication.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

Follow us on Facebook and Twitter for latest update.

SQL: Tips of the Day

Grouped LIMIT in PostgreSQL: Show the first N rows for each group?

db=# SELECT * FROM xxx;
 id | section_id | name
  1 |          1 | A
  2 |          1 | B
  3 |          1 | C
  4 |          1 | D
  5 |          2 | E
  6 |          2 | F
  7 |          3 | G
  8 |          2 | H
(8 rows)

I need the first 2 rows (ordered by name) for each section_id, i.e. a result similar to:

id | section_id | name
  1 |          1 | A
  2 |          1 | B
  5 |          2 | E
  6 |          2 | F
  7 |          3 | G
(5 rows)

PostgreSQL v9.3 you can do a lateral join

select distinct t_outer.section_id, t_top.id, t_top.name from t t_outer
join lateral (
    select * from t t_inner
    where t_inner.section_id = t_outer.section_id
    order by t_inner.name
    limit 2
) t_top on true
order by t_outer.section_id;

Database: PostgreSQL

Ref: https://bit.ly/3AfYwZI


We are closing our Disqus commenting system for some maintenanace issues. You may write to us at reach[at]yahoo[dot]com or visit us at Facebook