INSERT WITH TWO TABLES - PHP

Question

I have the table students and the table payments, I am doing a gym system. I linked the two tables by placing the id_students in the payments table as foreign key.

I want when registering student information and payment information, appear on the screen the data together of these two tables.

The registration of the student information (table students) is performed successfully, but the payment (table payments) does not enter in the bank anything...

I’ve tried to do with msql_insert_id and mysqli_insert_id but says that this does not exist, let alone the last_insert_id ...

CREATE.PHP

<?php
session_start();
include_once 'conexao.php';

$nome = filter_input(INPUT_POST, 'nome',FILTER_SANITIZE_SPECIAL_CHARS);
$cpf = filter_input(INPUT_POST, 'cpf', FILTER_SANITIZE_SPECIAL_CHARS);
$rg = filter_input(INPUT_POST, 'rg', FILTER_SANITIZE_SPECIAL_CHARS);
$nascimento = filter_input(INPUT_POST, 'nascimento', 
FILTER_SANITIZE_SPECIAL_CHARS);
$sexo = filter_input(INPUT_POST, 'sexo', FILTER_SANITIZE_SPECIAL_CHARS);
$fone = filter_input(INPUT_POST, 'fone', FILTER_SANITIZE_SPECIAL_CHARS);
$email = filter_input(INPUT_POST, 'email', FILTER_SANITIZE_SPECIAL_CHARS);
$endereco = filter_input(INPUT_POST, 'endereco', 
FILTER_SANITIZE_SPECIAL_CHARS);
$bairro = filter_input(INPUT_POST, 'bairro', FILTER_SANITIZE_SPECIAL_CHARS);
$cep = filter_input(INPUT_POST, 'cep', FILTER_SANITIZE_SPECIAL_CHARS);
$estado = filter_input(INPUT_POST, 'estado',FILTER_SANITIZE_SPECIAL_CHARS);
$cidade = filter_input(INPUT_POST, 'cidade', FILTER_SANITIZE_SPECIAL_CHARS);
$situacao_aluno = filter_input(INPUT_POST, 'situacao_aluno', 
FILTER_SANITIZE_SPECIAL_CHARS);
$validade_plano = filter_input(INPUT_POST, 'validade_plano', 
FILTER_SANITIZE_SPECIAL_CHARS);
$planos = filter_input(INPUT_POST, 'planos', FILTER_SANITIZE_SPECIAL_CHARS);
$vencimento = filter_input(INPUT_POST, 'vencimento', 
FILTER_SANITIZE_SPECIAL_CHARS);
$cpf_amigo = filter_input(INPUT_POST, 'cpf_amigo', 
FILTER_SANITIZE_SPECIAL_CHARS);
$forma_pagamento = filter_input(INPUT_POST, 'forma_pagamento', 
FILTER_SANITIZE_SPECIAL_CHARS);
$data_matricula = filter_input(INPUT_POST, 'data_matricula', 
FILTER_SANITIZE_SPECIAL_CHARS);
$numero_documento = filter_input(INPUT_POST, 'numero_documento', 
FILTER_SANITIZE_SPECIAL_CHARS);
$data_documento = filter_input(INPUT_POST, 'data_documento', 
FILTER_SANITIZE_SPECIAL_CHARS);
$valor = filter_input(INPUT_POST, 'valor', FILTER_SANITIZE_SPECIAL_CHARS);

$querySelect1 = $link->query("select email from alunos");
$array_emails = [];

while($emails = $querySelect1->fetch_assoc()):
$emails_existentes = $emails ['email'];
array_push($array_emails,$emails_existentes);
endwhile;

if(in_array($email,$array_emails)):
$_SESSION['msg'] = "<p class='center red-text'>".'Já existe um aluno com 
esse email'."</p>";
    header("Location:../");
else:
 $queryInsert1 = $link->query ("insert into alunos values(default,'$nome'
'$cpf','$rg','$nascimento','$sexo','$fone','$email','$endereco','$bairro', 
'$cep','$estado','$cidade')");

$queryInsert2 = $link->query("insert into pagamentos values(default, 
$situacao_aluno','$validade_plano','$planos','$vencimento',
'$cpf_amigo','$forma_pagamento','$data_matricula',
'$numero_documento','$data_documento','$valor')");


    $affected_rows = mysqli_affected_rows($link);

    if($affected_rows > 0):
        $_SESSION['msg'] = "<p class='center green-text'>".'Cadastro 
     efetuado com sucesso!'."</br>";
        header("Location:../cadastro.php");
    endif;
   endif;
  ?>

I no longer know what to do ... Someone knows this ?

Answer 1

Usa a função mysql_insert_id();

depois do insert aluno, vc usa mysql_insert_id() e grava em outra variavel.
Exemplo:
$aluno_ID = mysql_insert_id();

E depois usa essa variavel no seu insert pagamento