const regex = /AS "([^.]+)\.([^.]+)"(?<!AS "[^.]+\.\2"[\s\S]*AS "\1\.\2")(?![\s\S]*AS "[^.]+\.\2")/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('AS "([^.]+)\\.([^.]+)"(?<!AS "[^.]+\\.\\2"[\\s\\S]*AS "\\1\\.\\2")(?![\\s\\S]*AS "[^.]+\\.\\2")', 'gm')
const str = ` table1.field1 AS "table1.field1",
table2.field2 AS "table2.field2",
table3.field3 AS "table3.field3",
table4.field1 AS "table4.field1",
table4.field1 AS "table5.field5",
table6.field6 AS "table6.field1",`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions