JSFiddle - React, Tailwind, and code Playground

HTML

<div id="fixme">SELECT a, b, c, d FROM</div>
<br>
<button>Change text</button>

JavaScript

$("button").click(function() {
    var srctext = $("#fixme").text();
    console.log("old text: " + srctext);
    
    //var re = /.*SELECT\s+(.*)\s+FROM.*/;
    var newtext = srctext.replace(/(SELECT)(.+?)(?= FROM)/, "$1 count(*)");
    console.log("new text: " + newtext);
    
    $("#fixme").text(newtext)
});