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Basic SELECT Query
Filtering Data with WHERE Clauses
Sorting Data with ORDER BY
Using Aggregate Functions
Grouping Data with GROUP BY
Filtering Groups with HAVING
Joining Tables (INNER JOIN)
LEFT JOIN and NULL Handling
Combining Results with UNION
Medium
Subqueries for Complex Filtering
Using CASE Statements
Joining Tables (INNER JOIN)
  • Description: Learn how to join data from two tables using INNER JOIN. Retrieve each employee’s name along with their department name.
  • Table Used: employees, departments
    • employees Columns: employee_id, first_name, last_name, department_id, salary
    • departments Columns: department_id, department_name
  • Expected Columns Returned: employee_id, first_name, last_name, department_name
  • Schema:
classDiagram direction BT class departments { varchar(50) department_name int department_id } class employees { varchar(50) first_name varchar(50) last_name int department_id decimal(10,2) salary int employee_id } employees --> departments : department_id

select * from employees