从 PHP 中的外键引用获取列值

Question

My output is only id column, reference to "combustibili" table. How to get value reference from combustibili?

$combustibili = "SELECT * FROM tabelint";  
    $rezcom = $conectare->query($combustibili);
    $p = new GNUPlot();
    while($row = $rezcom->fetch_assoc()) {
      if($row["ID"] == 1){
        $data = new PGData($row["ID_BENZINA_STANDARD"]);
        $data2 = new PGData($row["ID_MOTORINA_STANDARD"]);
        $data3 = new PGData($row["ID_BENZINA_SUPERIOARA"]);
        $data4 = new PGData($row["ID_MOTORINA_SUPERIOARA"]);
      }
    }

Answer 1

From information provided assume COMBUSTIBILI table structure should be something like
COMBUSTIBILI(id pk and fk_in_tabelint number, name varchar, price float)
TABELINT(id pk number, ID_BENZINA_STANDARD fk->COMBUSTIBILI number... etc)
so
SELECT * FROM tabelint where id=1 will retun something like
(id #1, ID_BENZINA_STANDARD #2... etc)
and just need to query COMBUSTIBILI with fks

$combustibili = "SELECT * FROM tabelint";  
$rezcom = $conectare->query($combustibili);
$p = new GNUPlot();
//assume also record for id=1 exists
while($row = $rezcom->fetch_assoc()) {
  if($row["ID"] == 1){
    $data = new PGData($row["ID_BENZINA_STANDARD"]);
    $data2 = new PGData($row["ID_MOTORINA_STANDARD"]);
    $data3 = new PGData($row["ID_BENZINA_SUPERIOARA"]);
    $data4 = new PGData($row["ID_MOTORINA_SUPERIOARA"]);
  }
}
//add for each id_s
//BENZINA_STANDARD :: should be 1 row if db is consistent
//not sure how PGData class is defined and how to retrive only id : maybe $pgd->id ...
//$data = $row["ID_BENZINA_STANDARD"] : this is what is needed
$sql = "SELECT * FROM COMBUSTIBILI where id=".$data;
$sqlout = $conectare->query($sql);
//just parse and retrive what ever wanted
while($row = $sqlout->fetch_assoc()) { ... etc ... }

//same with data2_3_4