Page 483 - Computer_Science_F5

Computer Science (g) UNION
The ‘UNION’ operator is used to combine the result sets of two or more SELECT
statements. For example,
SELECT name FROM employees
FOR ONLINE READING ONLY
UNION
SELECT name FROM contractors;

(h) EXISTS
The ‘EXISTS’ operator checks whether any records exist in a subquery. For example,
SELECT name
FROM employees

WHERE EXISTS (SELECT 1 FROM departments WHERE departments.
department_id = employees.department_id);

(i) IN
The ‘IN’ operator allows you to specify multiple values in a WHERE clause. For
example,
SELECT name
FROM employees
WHERE department_id IN (1, 2, 3);

(j) BETWEEN
The ‘BETWEEN’ operator selects values within a given range. For example,

SELECT name, salary
FROM employees
WHERE salary BETWEEN 650000 AND 1250000;

(k) LIKE
The ‘LIKE’ operator is employed to find a particular pattern within a column. For
example,
SELECT name

FROM employees
WHERE name LIKE ‘J%’;

The pattern ‘J%’ in the WHERE clause selects names from the employees table where
the name column starts with ‘J’. Using ‘%’, a wildcard, matches any characters in
SQL queries. Thus, this query retrieves all names starting with ‘J’.

474
for Advanced Secondary Schools

Computer Science Form 5.indd 474 23/07/2024 12:35