diff --git a/src/services/articles.js b/src/services/articles.js
index dc7f3d1..92ccd27 100644
--- a/src/services/articles.js
+++ b/src/services/articles.js
@@ -35,7 +35,7 @@ async function listArticles({ limit = 20, offset = 0, tag = null, category = nul
   let sql = `SELECT id, slug, title, excerpt, cover_url, tags, category, author, reading_time, published_at
              FROM articles WHERE status='published'`;
   const params = [];
-  if (tag) { sql += ` AND tags ?? ${params.length + 1}`; params.push(tag); }
+  if (tag) { sql += ` AND tags ? ${params.length + 1}`; params.push(tag); }
   if (category) { sql += ` AND category=${params.length + 1}`; params.push(category); }
   sql += ` ORDER BY published_at DESC LIMIT $${params.length + 1} OFFSET $${params.length + 2}`;
   params.push(limit, offset);