2.2 KiB
2.2 KiB
Lecture 1 (13:00) - Sub-queries
- Aggregate functions cannot be used in a where clause. ex.
SELECT staffNo, name, position, salary
FROM staff
WHERE salary > ( SELECT AVG(salary) FROM STAFF )
IN Operator
- Used to check if an attribute has a value from a set of values.
- [NOT] IN (<value list>) ex.
SELECT name
FROM Drivers
WHERE address IN ("Dundee", "Aberdeen")
ex of IN used with subqueries. This would select all properties, their rooms and rent values, where their staff number matches a specific branch number
SELECT propertyNo, rooms, rent
FROM property
WHERE staffNo IN
( SELECT staffNo
FROM staff
WHERE branchNo = (
SELECT branchNo
FROM branch
WHERE street = "Main St"
)
);
Tutorial 2 (15:00) - SQL Sub-queries
- List the names of pirates who have pillaged booty of type bt3.
SELECT p-name
FROM pirates
WHERE p-code IN (
SELECT p-code
FROM pillage
WHERE boat-code = "b3"
)
);
- List the names of pirates who have pillaged any kind of fruit.
SELECT p-name
FROM pirates
WHERE p-code IN (
SELECT p-code
FROM pillage
WHERE booty-code IN (
SELECT booty-code
FROM booty
WHERE booty-name LIKE "%Fruit"
)
);
- List the names of booty whose value is greater than the average value of all the booty.
SELECT booty-name
FROM booty
WHERE value > (
SELECT AVG(value)
FROM booty
);
Workshop 2 (10:00)
-
List the names of the products whose number of units on order is greater than the average number of units in stock.
-
List the names of the products which have a value for UnitsInStock that is less than the average number of units in stock. Your query should also list the value for the UnitsInStock for each of these products. The results must be sorted into ascending order on UnitsInStock.
-
List names of the products whose number of units in stock is less than the average number of units in stock and whose number of units on order is less than the average number of units on order.
