So geben Sie die Anzahl der gefundenen Zeilen aus der SELECT-Abfrage zurück

Question

So geben Sie die Anzahl der gefundenen Zeilen aus der SELECT-Abfrage zurück

16

83499 2014-01-29

Ich habeeine Funktiongeschrieben,die die Anzahl derin einer SELECT-Abfragegefundenen Zeilen zurückgeben soll,aberimmerentweder 0 oderein Array zurückzugeben scheint. Ich habejetzt seit ungefähreiner Stunde damit rumgespielt und kannesimmernochnicht herausfinden! Ichbin sicher,ichmacheetwas dummesfalsch.

Die MySQL-Tabelle

 +--------+-------------+---------------------+
| 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

Quelle
Swen

- Wie heißt die Tabelle und das Tabellenpräfix?
  
  What is the name of the table and the table prefix?
  - 0
  - 2014-01-29
  - Chittaranjan
- @Chittaranjan Tabellennameist wp_postviews_ips,ichbin mirjedochnicht sicher,was Siemit Tabellenpräfixmeinen.
  
  @Chittaranjan Table name is wp_postviews_ips, I'm not sure what you mean by table prefix though.
  - 0
  - 2014-01-29
  - Swen
- Das Entfernen von "$ wpdb->" aus $ wpdb-> wp_postviews_ips schien den Trick zutun!
  
  Removing "$wpdb->" from $wpdb->wp_postviews_ips seemed to do the trick!
  - 0
  - 2014-01-29
  - Swen
- Aus diesem Grund hatteichnach dem Tabellennamen und dem Präfixgefragt.Alle WordPress-Tabellen habenein Präfix,das Siebeim Einrichten der WordPress-Sitefestgelegt haben.Hierfinden Sie weitere Details zu [Codex] (http://codex.wordpress.org/Creating_Tables_with_Plugins#Database_Table_Prefix). Bitte überprüfen Siemeine aktualisierte Antwort unter korrekter Verwendung des Tabellennamens.
  
  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 Antworten

Stimmen

- 2
- 2014-01-29
Scheint,dass die Abfragefalschist.$ipisteine Zeichenfolge,daher sollten Sie diese wiefolgtin einfache Anführungszeichen setzen

$wpdb->get_results("SELECT * FROM {$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'");
- Versuchte dies undesgibt immernoch 0 zurück.
  
  Tried this and it still returns 0.
  - 0
  - 2014-01-29
  - Swen

eteich · Accepted Answer · 2014-01-29

29

2014-01-29

Wenn Sie lediglich versuchen,eine Zählung zuerhalten,ist $wpdb->get_var(); zusammenmit der Verwendung von COUNT()in Ihrem SQLbesser:

 ### 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

Wasin Ihrem vorherigen Beispiel schiefgelaufenist,Sie haben Ihre $wpdb->get_results() -Instanz keiner Variablen zugewiesen,und ohne sie $wpdb->num_rows;gibt nur Null zurück,daesnicht aus der Instanz der Abfrage stammt,sondern aus demglobalen $ wbdb-Objekt.

Wenn Sie get_results() verwendenmöchten:

 ### 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

Aberich würde die Notwendigkeit dafürnicht sehen,wenn Sienicht die Ergebnissebenötigen. In diesem Fall würdeicheinfach das Objekt $ipquery zurückgeben und num_rows verwenden,wenn Ichbrauchtees:

 ### 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;

Kleine Ergänzung.Sie solltenimmerprepare (https://developer.wordpress.org/reference/classes/wpdb/prepare/) verwenden,wenn Sie Abfragen ausführen,umeine SQL-Injection zu verhindern.

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
Eigentlich sollte das keine kleine Ergänzung sein,dasist sehr wichtig,um Ihren Codenicht über SQL Injection ausnutzbar zumachen.

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