MySQL Database Query Work - Need to parse some data and make usable

We need someone to pull info off our MySQL database and rework it to be more usable. More specifically, we need to do the following: In a MySQL database we have a meta_key called: "score_record" and a meta_key called: "act_score_record". The "meta_value" of each of these rows looks something like this: "a:3:{i:0;a:9:{s:8:"engscore";s:2:"26";s:9:"engmissed";s:1:"4";s:9:"mathscore";s:2:"21";s:10:"mathmissed";s:2:"11";s:8:"sciscore";s:2:"21";s:9:"scimissed";s:1:"7";s:9:"readscore";s:2:"24";s:10:"readmissed";s:2:"10";s:4:"date";i:1424446035;}i:1;a:9:{s:8:"engscore";s:2:"32";s:9:"engmissed";s:1:"3";s:9:"mathscore";s:2:"24";s:10:"mathmissed";s:2:"14";s:8:"sciscore";s:2:"22";s:9:"scimissed";s:2:"10";s:9:"readscore";s:2:"23";s:10:"readmissed";s:2:"10";s:4:"date";i:1425159028;}i:2;a:9:{s:8:"engscore";s:2:"28";s:9:"engmissed";s:1:"3";s:9:"mathscore";s:2:"20";s:10:"mathmissed";s:2:"15";s:8:"sciscore";s:2:"21";s:9:"scimissed";s:2:"12";s:9:"readscore";s:2:"28";s:10:"readmissed";s:2:"10";s:4:"date";i:1428878101;}}" The data in here are practice test scores from multiple attempts at the same test. You can see in the quotes '"mathscore"' and then the next quoted item is '"24"', meaning on that test the person got a 24 on the math section. For each of these rows need to find the lowest score and the highest score someone got on the tests in each section. In this example it appears the lowest math score was 20, the highest 24. We need this for each section on each user. We will then use this info to determine average score changes within our data.