SQL Playground
Write queries, analyze performance, and learn optimization techniques
Query Editor
Sample queries:
Ready to analyze
Enter a query above and click "Analyze Query" to see results, insights, and optimization suggestions.
employees
20 rows
PK
id
name
FK
department_id
FK
manager_id
salary
hire_date
email
phone
departments
6 rows
PK
id
name
budget
location
customers
10 rows
PK
id
name
email
city
country
credit_limit
created_at
products
12 rows
PK
id
name
category
price
stock_quantity
weight
is_active
orders
15 rows
PK
id
FK
customer_id
FK
employee_id
order_date
shipped_date
status
notes
order_items
26 rows
PK
id
FK
order_id
FK
product_id
quantity
unit_price
discount
Relationships
departments
->
employees
(department_id)
employees
->
employees
(manager_id)
customers
->
orders
(customer_id)
employees
->
orders
(employee_id)
orders
->
products
(order_items)
Try These Exercises
- Write a query with
SELECT *and see the warning, then fix it - Try
WHERE YEAR(order_date) = 2023and see the suggested rewrite - Experiment with
LIKE '%phone%'to understand wildcard issues - Check the EXPLAIN tab to understand how MySQL would execute your query