Cómo devolver el número de filas encontradas de la consulta SELECT

Question

Cómo devolver el número de filas encontradas de la consulta SELECT

16

83499 2014-01-29

Escribí unafunción que se supone que devuelveelnúmero defilasencontradasen una consulta SELECTpero siempreparece devolver 0 o unamatriz. ¡Heestadojugando conesto durante aproximadamente una hora ytodavíanopuedo resolverlo! Estoy seguro de queestoy haciendo algoestúpidamentemal.

Latabla MySQL

 +--------+-------------+---------------------+
| postid |     ip      |        time         |
+--------+-------------+---------------------+
|   1234 | 192.168.0.1 | 2014-01-29 14:27:02 |
|   5678 | 192.168.0.2 | 2014-01-29 14:27:02 |
+--------+-------------+---------------------+

PHP

 ### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = $ip");

    $rowcount = $wpdb->num_rows;

    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

I wrote a function which is supposed to return the number of rows found in a SELECT query but it always either seems to return 0 or an array. I have been messing around with this for about an hour now and I still can't figure it out! I'm sure I'm doing something stupidly wrong.

The MySQL Table

+--------+-------------+---------------------+
| postid |     ip      |        time         |
+--------+-------------+---------------------+
|   1234 | 192.168.0.1 | 2014-01-29 14:27:02 |
|   5678 | 192.168.0.2 | 2014-01-29 14:27:02 |
+--------+-------------+---------------------+

PHP

### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = $ip");

    $rowcount = $wpdb->num_rows;

    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

fuente
Swen

- ¿Cuáleselnombre de latabla yelprefijo de latabla?
  
  What is the name of the table and the table prefix?
  - 0
  - 2014-01-29
  - Chittaranjan
- @Chittaranjan Elnombre de latablaes wp_postviews_ips,aunquenoestoy seguro de a quéte refieres conelprefijo de latabla.
  
  @Chittaranjan Table name is wp_postviews_ips, I'm not sure what you mean by table prefix though.
  - 0
  - 2014-01-29
  - Swen
- ¡Laeliminación de "$ wpdb->" de $ wpdb-> wp_postviews_ipsparecíafuncionar!
  
  Removing "$wpdb->" from $wpdb->wp_postviews_ips seemed to do the trick!
  - 0
  - 2014-01-29
  - Swen
- Esaes la razónpor la quepedíelnombre yelprefijo de latabla.Todas lastablas de wordpresstienen unprefijo que seestablece durante la configuración del sitio de wordpress.Aquí haymás detalles sobre [codex] (http://codex.wordpress.org/Creating_Tables_with_Plugins#Database_Table_Prefix) Verifiquemi respuesta actualizada conel uso correcto delnombre de latabla.
  
  That's the reason I had asked for the table name and prefix. All wordpress tables have a prefix which you set during setting up the wordpress site. Here are more details on [codex](http://codex.wordpress.org/Creating_Tables_with_Plugins#Database_Table_Prefix) Please check my updated answer with correct use of table name.
  - 0
  - 2014-01-29
  - Chittaranjan

2 respuestas

votos

- 2
- 2014-01-29
Parece que la consultaesincorrecta.$ipes una cadena,por lo que debeponerloentre comillas como semuestra a continuación

$wpdb->get_results("SELECT * FROM {$wpdb->prefix}postviews_ips WHERE postid = $id AND ip = '$ip'");
Seems the query is wrong. $ip is string so you should put single quote around that as below

$wpdb->get_results("SELECT * FROM {$wpdb->prefix}postviews_ips WHERE postid = $id AND ip = '$ip'");
- Intentéesto ytodavía devuelve 0.
  
  Tried this and it still returns 0.
  - 0
  - 2014-01-29
  - Swen

eteich · Accepted Answer · 2014-01-29

29

2014-01-29

Si simplementeestátratando de obtener un recuento,$wpdb->get_var();junto conel uso de COUNT()en su sql serámejor:

 ### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $rowcount = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");

    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

En cuanto a lo que saliómalen suejemplo anterior,noestaba asignando suinstancia $wpdb->get_results() a una variable,y sinella $wpdb->num_rows; solo devolverá cero,ya queen realidadno seextrae de lainstancia de la consulta,sino del objetoglobal $ wbdb.

Si desea utilizar get_results():

 ### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $ipquery= $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");
    $rowcount = $ipquery->num_rows;
    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

Perono vería lanecesidad deeso amenos quenecesitara los resultados,en cuyo caso simplemente devolveríael objeto $ipquery y usaría num_rowsen él cuando Lonecesitaba:

 ### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $ipquery = $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");
    return $ipquery;
}

$someVariable = postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

echo $someVariable->num_rows;

If you are merely trying to get a count, $wpdb->get_var(); along with using COUNT() in your sql will be better:

### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $rowcount = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");

    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

As to what went wrong in your previous example, you weren't assigning your $wpdb->get_results() instance to a variable, and without it $wpdb->num_rows; is just going to return zero as it isn't actually pulling from the instance of the query, but rather the global $wbdb object.

If you do want to use get_results():

### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $ipquery= $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");
    $rowcount = $ipquery->num_rows;
    return $rowcount;
}

postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

But I wouldn't see the need for that unless you needed the results, in which case I would just return the $ipquery object and use num_rows on it when I needed it:

### Search for IP in database
function postviews_get_ip($id, $ip) {
    global $post, $wpdb;

    $ipquery = $wpdb->get_results("SELECT * FROM $wpdb->wp_postviews_ips WHERE postid = $id AND ip = '$ip'");
    return $ipquery;
}

$someVariable = postviews_get_ip($id, $_SERVER['REMOTE_ADDR']);
//both $id and $_SERVER['REMOTE_ADDR']) return the values I'm searching for in the database

echo $someVariable->num_rows;

Pequeña adición.Siempre debe usarprepare (https://developer.wordpress.org/reference/classes/wpdb/prepare/) cuandoejecute cualquier consultaparaevitar lainyección de SQL.

Small addition. You should always use prepare (https://developer.wordpress.org/reference/classes/wpdb/prepare/) when executing any queries to prevent sql injection.
- 1
- 2019-05-29
- Maciej Paprocki
En realidad,esono debería ser unapequeña adición,esoesmuyimportanteparano hacer que su código seaexplotable através de lainyección SQL.

Actually that shouldnt be a small addition, that's very important not to make your code exploitable via sql injection.
- 0
- 2019-09-12
- Max Carroll