“警告”错误PHP [重复]

Question

This question already has an answer here:

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I need help with this:

 $query="SELECT productos.id_producto, productos.nombre, productos.precio, 
 ci.quantity, ci.quantity * productos.precio AS subtotal  
        FROM productos p  
            LEFT JOIN cart_items ci 
                ON ci.id_producto = productos.id_producto"; 
 $com = mysqli_query($cnx, $query);
 $row = mysqli_fetch_assoc($com);

Warning: mysqli_fetch_assoc() expects parameter 1 to be mysqli_result, string given in "XXXXX" on line 34

In this case is line = 6.

Sorry if this is "simple php" error.

I'm learning PHP.

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Answer 1

You have an error on your SQL statement. You've given an alias to your table productos as p but your calling the fields using the table name itself. Try to remove the alias name and you're good to go.

$query="SELECT productos.id_producto, productos.nombre, productos.precio, 
 ci.quantity, (ci.quantity * productos.precio) AS subtotal  
        FROM productos  
            LEFT JOIN cart_items ci 
                ON ci.id_producto = productos.id_producto";

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