SELECT SUM(x.FloatAmount) FROM filetransaction ftCROSS APPLY ( SELECT FloatAmount = CASE WHEN ISNUMERIC(ft.amount) = 1 THEN CAST(ft.amount AS FLOAT) ELSE 0 END) x WHERE 1 = 1

SELECT sum(CONVERT(float, ft.amount)) FROM filetransaction ft WHERE ft.fileid <>332 and ISNUMERIC(ft.amount)=1

SELECT sum(CONVERT(float, ft.amount)) FROM filetransaction ft WHERE ISNUMERIC(ft.amount)=1