The SELECT statement is the primary way to retrieve data from one or more tables in MySQL. It lets you choose specific columns, filter rows, transform values, combine tables, and control the order and volume of the returned results.
Key Points: • SELECT column_list FROM table specifies exactly which columns to retrieve rather than returning entire rows. • WHERE filters which rows are included based on a condition. • Aggregate functions such as SUM, AVG, COUNT, MIN, and MAX transform the retrieved data into summary values. • JOIN combines related data from multiple tables based on a matching column. • ORDER BY sorts results, and LIMIT caps the number of rows returned.
Example: To see just the names and positions of all employees rather than every column in the employees table, you'd run a SELECT that lists only those two columns.
Code Example:
SELECT name, position
FROM employees
WHERE position = 'Engineer'
ORDER BY name
LIMIT 10;Interview Tip: A concise interview answer is:
"SELECT is how you retrieve and shape data from one or more tables -- picking specific columns, filtering with WHERE, aggregating with functions like SUM or COUNT, joining across tables, and controlling order and row count with ORDER BY and LIMIT. It's the core read operation almost every application relies on."