为什么在将服务器更改为 PHP 7.3 后此查询会出现此错误

Question

Warning [2] Use of undefined constant mybb_ - assumed 'mybb_' (this will throw an Error in a future version of PHP) - Line: 8 - File: index.php(432): eval()'d code(70): eval()'d code PHP 7.3.28 (Linux)

I tried to fix it by myself of course and I have an idea what this error means, but I can not find a forgotten $ or "" or ''?

$query = $db->query("
    SELECT t.tid, t.fid, t.uid, t.username, t.subject, t.replies, t.views, t.lastposter, p.message
    FROM " . mybb_ . "threads t
    INNER JOIN " . mybb_ . "posts p ON (p.tid=t.tid)
    WHERE t.fid='333' AND t.visible='1'
    ORDER BY t.dateline DESC
    LIMIT 6"

What have I overlooked?

Answer 1

it looks like your sql is wrong. You can use SQL validator Right here: https://www.eversql.com/sql-syntax-check-validator/