I've got to re-learn my MySQL and PHP programming skills . I have a field name contentdata with a hex data of AA560D72DA4AB20AAA using a type char. In MySQL, I can run this command: SELECT SUBSTR(hex(contentdata),15,2) FROM table1 output is: 0A How can I code " SELECT SUBSTR(hex(contentdata),15,2) FROM table1 " in PHP so I can bring the same result? MySQL create php code gave me this recommendation but I can't show the value. $sql = "SELECT SUBSTR(hex(payload),15,2) FROM device_status LIMIT" Let me know what I'm missing here? UPDATE: A member (Katherine) in domain name forum recommended to use "AS hex_value" to create aliases for the field resulting from expressions. It works! So, I query the data using the codes below: " SELECT SUBSTR(hex(contentdata),15,2) AS myHex_data FROM table1 "