Write a query to return every staging_orders.order_ref with a numeric amount and a format reason, after trimming amount_text.
Use missing for NULL or empty trimmed values. Use ok only for unsigned digits with an optional decimal part of one or two digits, either without commas or with correctly grouped thousands commas. Leading zeros are allowed. Any other value is bad_format, including a value with three decimal places such as 1.800.
Convert only ok values, removing thousands commas and keeping their decimals. Return NULL for amount on missing or bad-format rows.
Ordering: Sort by order_ref in ascending order.