Conversion from INT to HEX

SELECT CONVERT(VARBINARY(8), 256)

Converting from HEX to INT

SELECT CONVERT(INT, 0x00000100)
 

SELECT 0x00000100*1 HextoInt

from:http://blog.sqlauthority.com/2012/07/26/sql-server-answer-how-to-convert-hex-to-decimal-or-int/