CASE
statement to check if the income is less than 20000, between 20000 and 50000, or greater than 50000.SUM
function to count the number of accounts that fall into each category based on the CASE
statement.UNION
to combine the results of the three categories into a single result set.sum()
method to count the number of True values, which correspond to the number of accounts in each category.erDiagram Accounts { int account_id int income }