两个表的内部联接[更新]

Question

tbl teacher

lrn
fname
lname
email
image
schedule

tbl user

lrn
fname
lname
email
image
account-type

$id=$_SESSION['id'];

$get_record_sched = mysqli_query ($db, "SELECT schedule FROM teacher INNER JOIN users ON teacher.lrn = users.lrn WHERE teacher.lrn = '$id' ");

I want to echo the exact schedule based on the id of the logged in account. But with this, query, there's no output...

Answer 1

You said you have $id from the session. Assuming that column lrn is the ID, then

Select t.schedule
From teacher t
Where t.lrn = $id

No need to join the table with the user table.

Note that parameter binding is advised.

$statement = $connection->prepare("Select t.schedule From teacher t Where t.lrn = ?");
$statement->bind_param("s", $id);

Answer 2

In you where condition was wrong.They don't have any param to validate condition.so change like this

"SELECT schedule FROM teacher INNER JOIN users  ON teacher.id = users.id WHERE 1  "

OR

use same where condition with join

"SELECT schedule FROM teacher INNER JOIN users  ON teacher.id = users.id AND teacher.schedule = users.id   WHERE 1  "

OR

if You have logged used id in session like

$id=$_SESSION['user_id'];

"SELECT schedule FROM teacher INNER JOIN users ON teacher.id = users.id WHERE teacher.schedule='$id' "