sqlserver varchar转数字进行范围查询

SELECT COUNT
	( [size] ) num 
FROM
	crawler_publish_property 
WHERE
	CAST ( ISNULL( [size], 0 ) AS NUMERIC ( 10, 2 ) ) >= 0 
	AND CAST ( ISNULL( [size], 0 ) AS NUMERIC ( 10, 2 ) ) < 50

Numeric(10,2)表示总位数为10，小数点后为2位的数，也就是说这个字段的整数位最大是8位