Use of case in SQL why and when we use it.

Question

Accepted Answer

CASE in SQL is used to apply conditional logic to queries and manipulate data based on specific conditions.

CASE is used to create conditional expressions in SQL
It allows for the manipulation of data based on specific conditions
CASE can be used in SELECT, WHERE, and ORDER BY clauses
It can be used to create calculated fields or to filter data based on specific criteria
CASE can also be used in conjunction with aggregate functions like SUM and COUNT
Example: SELECT name, CASE WHEN age > 18 THEN 'Adult' ELSE 'Minor' END AS age_group FROM customers
Example: SELECT product_name, CASE WHEN price > 100 THEN 'Expensive' ELSE 'Affordable' END AS price_category FROM products
Example: SELECT category, SUM(CASE WHEN status = 'Shipped' THEN 1 ELSE 0 END) AS shipped_count FROM orders GROUP BY category

Top Amazon Business Analyst interview questions & answers