Use Convert() to add two digits the end of a number and a comma to the left?

I’m asked to use the CONVERT function to return the third column as a datatype that outputs 2 digits to the right of the decimal point and all comma’s to the left (i.e. 3, 106.34). Name it FormatTotal.

This is where I’m at.

USE AP

SELECT InvoiceTotal,
    CAST(InvoiceTotal AS int) intTotal,
    CAST(InvoiceTotal AS decimal(8,1)) DecimalTotal
    CONVERT(decimal(???), InvoiceTotal) AS FormatTotal
FROM Invoices;

Answer

This looks like a task for format():

format(InvoiceTotal, 'N2', 'en-US') as FormatTotal

N is the format specifier for numbers.

2 gives you the precision (ie the number of decimal digits).

en-US defines the comma separator for thousands and the dot separator for decimals.