JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.full.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/alasql@4.5.1/dist/alasql.min.js"></script>
<xmp id="output"></xmp>

JavaScript

var data = [
    { age: 5 },
    { age: 15 },
    { age: 25 },
   // { age: 30 },
];

var sql = `
    SELECT 
        CASE 
            WHEN age BETWEEN 0 AND 9 THEN '0-9'
            WHEN age BETWEEN 10 AND 19 THEN '10-19'
            WHEN age BETWEEN 20 AND 29 THEN '20-29'
            ELSE '30+'
        END AS age_group 
        
    FROM ? 
  GROUP BY age_group 
`;

var res = alasql(sql, [data]);

print(res);






function print(x){
    document.getElementById('output').textContent += JSON.stringify(x,  null, '\t')+"\n";
}
print('AlaSQL v'+alasql.version)