Finding the Highest and Lowest values of a Dataset

SELECT 'After 1/1/2018' AS selection_date,

COUNT(*) AS number_of_invoices,

MAX(invoice_total) AS highest_invoice_total,

MIN(invoice_total) AS lowest_invoice_total

FROM invoices

WHERE invoice_date > '2018-01-01'

Notice you are manually maintaining this integrity

The Output for this Query