使用PDO根据另一个表的第一个值查询MYSQL数据库

Hi I am having trouble querying a mysql table based on the first value of another table here is my code.

<?php

$host    = 'localhost';
$db      = 'msdds';
$user    = 'root';
$pass    = '';
$charset = 'utf8';



$dsn = "mysql:host=$host;dbname=$db;charset=$charset";



$opt = [
        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES   => false,
        ];


$dbh = new PDO($dsn, $user, $pass, $opt);



$sql  = $dbh->query("SELECT name FROM employee WHERE remarks != 'done' and branch ='EGYPT' and tenure=""");
$rows = $sql->fetchAll();
echo json_encode($rows);



?>

I want to add a query on tenure based on the first value of another table. I need to query from another table currently it is connected to employee table but I have another table that contains tenure and based on the first value there will be the content of tenure

Replace your Query with this

$sql = $dbh->query("SELECT name FROM employee WHERE remarks != 'done' AND (branch ='EGYPT' and tenure='')");

$rows = $sql->fetchAll();

tenure is also equal to single quote.