Sql query to convert nvarchar to int

Question

I have to query for total amount of a column using an aggregate function. The column data type is NVARCHAR(MAX). How can I convert it to Integer?

I have tried this:

Answer 1

In addition to gbn's answer, you need to protect against non-numeric cases:

sum(CASE WHEN ISNUMERIC(Amount)=1 THEN CAST(CAST(amount AS float) AS INT)END )