How to do multiple inserts at one time?

Well I have 3 tables in my database, and I make a INSERT in the sale table, and as soon as I enter the data in it automatically I would have to insert into the and the vendaproduct table that would be this code:

if(isset($_POST['send'])){
$venda = $_POST['num_venda'];
$data = $_POST['data_venda'];
$placa = $_POST['placa'];
$km = $_POST['km'];
$produtos = $_POST['produtos'];
$servicos = $_POST['servicos'];


include ('banco.php');


mysql_query("INSERT INTO venda(id_venda, num_venda, data_venda, placa, km, produtos, servicos)
        values(
            NULL,
            '{$venda}',
            '{$data}',
            '{$placa}',
            '{$km}',
            '{$produtos}',
            '{$servicos}'

                        )
        ");

mysql_query("INSERT INTO vendaproduto (id, id_venda, produtos)
          SELECT venda.id_venda, venda.id_venda, venda.produtos
          FROM venda");

mysql_query("INSERT INTO vendaservico (id, id_venda, servicos)
          SELECT venda.id_venda, venda.id_venda, venda.servicos
          FROM venda") ;

header("location:lista.php");}

The first time I tested the code it worked, but now every time I try not to insert the vendaproduct and saleservic tables, just insert the data into the table sale.

The error is as follows: Duplicate entry '1' for key 'PRIMARY'

Can I still use mysql_ to interfere with something in my code?

Use the mysql_insert_id function to get the last record entered in sales. Then you can do insert with select but this time add a where, which compares the id with the last record inserted

if(mysql_query("INSERT INTO venda ... ")){
    $id = mysql_last_id();

    mysql_query("INSERT INTO vendaproduto (id, id_venda, produtos)
          SELECT venda.id_venda, venda.id_venda, venda.produtos
          FROM venda WHERE id = $id") or die(mysql_error());

    mysql_query("INSERT INTO vendaservico (id, id_venda, servicos)
          SELECT venda.id_venda, venda.id_venda, venda.servicos
          FROM venda WHERE id = $id") or die(mysql_error());  
}

Apparently the error you are giving is that you are trying to insert duplicate values into a single value field.

But to insert multiple values with an insert just do this:

INSERT INTO 'usuarios' ('id', 'nome', 'email') VALUES (123, 'Fulano da Silva', 'fulano@email.com'), (32, 'Ciclano', 'ciclano@uol.com.br')

You are inserting duplicate ID’s in the vendaproduto and vendaservico table.
If the “id” column is auto-incremental you can omit the ID column.

It would look like this:

mysql_query("INSERT INTO vendaproduto (id_venda, produtos)
      SELECT venda.id_venda, venda.produtos
      FROM venda");

mysql_query("INSERT INTO vendaservico (id_venda, servicos)
      SELECT venda.id_venda, venda.servicos
      FROM venda") ;