Check First on Table A, if not found Check on other table - php

Question

I am creating a Log in and I have separate tables for Users A and Users B.
What I want to do is check first in first table if the Users that trying to Login is in the Table A,
if YES, it will not go to the Table B to check the Login credentials, if NOT, go to Table B and check the Login credentials.
Table A
SELECT * FROM tableA WHERE userId='$userId' AND password='$password'
Table B
SELECT * FROM tableB WHERE accountNumber='$accountNumber' AND password='$password'
Note: The 2 Tables has different Field Name userId and accountNumber.

Answer 1

I presume you are fetching the values of username and password from client side so I will tell you only what you asked for.
$getUserBasic1=$db->prepare('SELECT * FROM tableA WHERE userId="$userId" AND password="$password"');
$getUserBasic1->execute();
$user= $getUserBasic1->fetchAll();
if(count($user)>0)
{
//if yes do what you want here
}
else
{
$getUserBasic2=$db2->prepare('SELECT * FROM tableB WHERE accountNumber="$accountNumber" AND password="$password"');
$getUserBasic2->execute();
$user2= $getUserBasic2->fetchAll();
//write your code here
}

Answer 2

You could use an INNER JOIN and select both table results taking Table A's result first if it exists, else take Table B's result.
Assuming both tables have some sort of reference like the User ID you can use something like this:
SELECT tbla.*, tblb.* FROM tableA tbla
INNER JOIN tableB tblb ON tbla.userId = tblb.userId
WHERE userId='$userId' OR accountNumber='$accountNumber' AND password='$password'
ORDER BY userId ASC
LIMIT 1
The query above uses the cross-reference (userId in this case) and joins both tables together before querying the results. It orders the results by Table A before Table B but limits the result to 1 bringing either Table A or Table B out depending which is null.

Answer 3

Try combining the tables, some thing like:
SELECT * FROM tableA, tableB WHERE tableA.userId='$userId' AND tableA.password='$password' OR tableB.accountNumber='$accountNumber' AND tableB.password='$password'
I have not checked, so may not work, but see if this gets what you are looking for!

Answer 4

Something like this:
$sql = "SQL QUERY FOR TABLEA";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// checking if result in TABLE A
}
else{
//search in TABLE B by updating your sql value.
}
I hope that you want to check for the registered user, the best way to do that is to keep one table and just search there itself keeping the userID as the primary key.