使用共享字段（mysql和php）从两个不同的表打印数据

Question

I'm trying to bring data from two different tables where there is a shared field: in table1, I have many fields and one of them is the employee Position which is a number. in table2 I have two fields: EmpPos (which is equal to Position in table1) and PosName . Now, I want to print all employees' info from table1 but instead of printing Position (which is a number), I want to print its associated PosName from table2. My following query is not working!

$sql ="SELECT * FROM table1, table2 WHERE table1.Position=table2.EmpPos";
$result = $conn->query($sql);

if ($result->num_rows > 0) {

    <tr>
        <th>Name</th>
        <th>Email</th>
        <th>Position Name</th>
        <th>phoneExt</th>

    </tr>";

    while($row = $result->fetch_assoc()) {
        echo "<tr>";
        echo "<td>" .$row['table1.FirstName'] ." " .$row['table1.LastName'] ."</td>";
        echo "<td>" .$row['table1.Email'] ."</td>";
        echo "<td>" .$row['table2.PosName'] ."</td>";
        echo "<td>" .$row['table1.phoneExt'] ."</td>";
        echo"</tr>";
}

Thanks in advance

Answer 1

The issue is you didn't define any relationship between the tables. So you should be using INNER or LEFT JOIN for this:

SELECT * FROM Table1 m INNER JOIN
Table2 k ON k.EmpPos = m.Position

Or the following should do:

SELECT * FROM Table1 m LEFT JOIN
Table2 k ON k.EmpPos = m.Position

As you have a foreign key (Shared field), then it's easy and obvious to use joins.

Answer 2

使用内部联接

SELECT * FROM table1 tab1 INNER JOIN table2 tab2 ON tab1.position = tab2.EmpPos