SELECT Statements Estimated reading: 2 minutes 20 views 1. Write a query to fetch specific columns from a tableTo fetch specific columns, use the SELECT statement followed by the column names you need.Example: SELECT name, salary FROM employees; 2. How do you retrieve all rows and columns from a table?Use SELECT * to fetch all rows and columns from the table.Example: SELECT * FROM employees; 3. What is the use of aliases (AS keyword) in a SELECT statement? Provide an example.Aliases are used to give columns or tables a temporary name for better readability or convenience.Example: SELECT name AS EmployeeName, salary AS EmployeeSalary FROM employees; 4. How do you use mathematical expressions or calculated fields in a SELECT query?You can use arithmetic expressions like addition, subtraction, multiplication, and division to calculate new fields.Example: SELECT name, salary * 12 AS AnnualSalary FROM employees; 5. Write a query to combine columns from multiple tables using a JOINUse the JOIN clause to combine columns from multiple tables based on a related column.Example: SELECT e.name, d.department_name FROM employees e JOIN departments d ON e.department_id = d.id; 6. How can you fetch the first N rows from a table using SQL?In Oracle, you can use ROWNUM to limit the number of rows returned.Example: SELECT * FROM employees WHERE ROWNUM <= 5;
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