Mysqli查询一行

Question

The current procedure I am using to run a simple SQL query is the following:

$a = $mysqli->query("SELECT column FROM table");
$b = $a->fetch_assoc();
$c = $b["column"];

This uses 3 different variable names and it gets frustrating trying to come up with suitable names. I think that in the procedural style, I can run this in two lines as oppose to three:

$a = mysql_fetch_assoc(mysql_query("SELECT column FROM table"));
$b = $a["column"];

Is there any approach to use the object-oriented style in just one line of code?

Answer 1

Why don't you use OOP that you are already using? If I'm not mistaken, you could use the facade design pattern. This is not exactly one line of code but it is more of a write once.

Create an object to do the querying.

//This is just a rough idea
class SimpleQuery {

    protected $mysqli;

    function __construct() {
       //Get a connection using whatever way you want
    }

    /**
     * @param string $query The query to execute
     * @param string $field The field to return(optional)
     * @return mixed
     */
    function query($query, $field = NULL) {

      $a = $this->mysqli->query($query);
      $b = $a->fetch_assoc($a);

      //Obviously this function needs to be adjusted to do what you seek, get multiple rows perhas
      if ($field) {
         return $b[$field];
      } else {
         return $b;
      }

    }

}

Then you can simply just:

$simpleQuery = new SimpleQuery();

$dbData = $simpleQuery->query('SELECT column FROM table','column');

Don't know if this works for you but it's worth writing. The reason objects were created, to be reusable. :-)

Answer 2

Is there any approach to use the object-oriented style in just one line of code?

Sure.
This is what object-oriented style exactly for.

However, you don't quite understand the idea of the object-oriented style.
The idea is, actually, is not to throw some OO-methods together to get some awkward and unreliable construct, but to create a class , which will have methods for all your needs.

@Touch's is absolutely right with his answer, but of course it's only a sketch. Such a class have to be extended to have all the methods you need:

Say, to have a column from table,

$a = $db->getOne("SELECT column FROM table LIMIT 1");

Or to get a whole row:

$row = $db->getRow("SELECT * FROM table LIMIT 1");

or all the rows

$data = $db->getAll("SELECT * FROM table");

You may note that these snippets is not only shorter than silly approaches from other answers, but also have error reporting, query logging, profiling and many other useful things implemented already.

You should also take into account that placeholders support is a must! Otherwise all this stuff will be totally useless . Note that dedicated OO-based solution is the only way to keep the code in one line: with raw API methods you'll end up not with one but with dozen lines at the very least.

Yet such a class can keep one-liners all right:

$name = $db->getOne('SELECT name FROM table WHERE id = ?i',$_GET['id']);
$data = $db->getInd('id','SELECT * FROM ?n WHERE id IN ?a','table', array(1,2));
$data = $db->getAll("SELECT * FROM ?n WHERE mod=?s LIMIT ?i",$table,$mod,$limit);

Here is an example of a class I am talking about. , which you can use already.

Answer 3

There's nothing stopping you form using

$mysqli->query($query)->fetch_assoc()["column"];

Typical names are:

• $a -- $result
• $b -- $row
• $c -- $column

Answer 4

You should check this query before fetch();

I recommend use this:

    $query = mysql_query("SELECT column FROM table");
    if ($query)
    {
       $data = mysql_fetch_assoc($query);
    }
    else
    {
     echo mysql_error($query);
    }

If you will use one line mysql query for fetch result you have a problem with debug if query fails.