Count salary categories

#
# Table: Accounts
# +-------------+------+
# | Column Name | Type |
# +-------------+------+
# | account_id  | int  |
# | income      | int  |
# +-------------+------+
# account_id is the primary key (column with unique values) for this table.
# Each row contains information about the monthly income for one bank account.
# Write a solution to calculate the number of bank accounts for each salary category. The salary categories are:
# "Low Salary": All the salaries strictly less than $20000.
# "Average Salary": All the salaries in the inclusive range [$20000, $50000].
# "High Salary": All the salaries strictly greater than $50000.
# The result table must contain all three categories. If there are no accounts in a category, return 0.
# Return the result table in any order.
# The result format is in the following example.
# Example 1:
# Input:
# Accounts table:
# +------------+--------+
# | account_id | income |
# +------------+--------+
# | 3          | 108939 |
# | 2          | 12747  |
# | 8          | 87709  |
# | 6          | 91796  |
# +------------+--------+
# Output:
# +----------------+----------------+
# | category       | accounts_count |
# +----------------+----------------+
# | Low Salary     | 1              |
# | Average Salary | 0              |
# | High Salary    | 3              |
# +----------------+----------------+
# Explanation:
# Low Salary: Account 2.
# Average Salary: No accounts.
# High Salary: Accounts 3, 6, and 8.
#

# Write your MySQL query statement below

SELECT 'Low Salary' AS category, COUNT(*) AS accounts_count
FROM Accounts WHERE income < 20000
UNION ALL
SELECT 'Average Salary', COUNT(*)
FROM Accounts WHERE income BETWEEN 20000 AND 50000
UNION ALL
SELECT 'High Salary', COUNT(*)
FROM Accounts WHERE income > 50000;