如何在sql语句中使用来自sql数据库的数组

Question

I'm probably going in the complete wrong direction but I want to get an array of data from the database and then use that array in another SQL statement.

Here is my current code:

  $result = mysql_query($query_friend_club_count) or die(mysql_error());

  while($row = mysql_fetch_array($result)){
  $row['idPerson']. " - ". $row['idFriend'];
  $idFriend = $row['idFriend'];
  $array = $idFriend',';

  $query_friends = "SELECT * FROM whosout WHERE idPerson IN ('$array')";
  $query_friends_run = mysql_query($query_friends);
  $friendCounter = mysql_num_rows($query_friends_run);

  echo $friendCounter;
  } 

I'm getting a error of:

syntax error, unexpected T_CONSTANT_ENCAPSED_STRING

Don't know if that helps.

Any suggestions would be really helpful as I've been stuck on this for ages!!

Answer 1

You can also group them first instead of quering them each:

$array = array();
while($row = mysql_fetch_array($result)){
    $array[] = mysql_escape_string($row['idFriend']); // escape just to be sure
}

$array = "'".implode("','", $array) . "'"; // comma separated values

$query_friends = "SELECT * FROM whosout WHERE idPerson IN ($array)";
$query_friends_run = mysql_query($query_friends);
$friendCounter = mysql_num_rows($query_friends_run);
echo $friendCounter;

Or if this column is an INT, no need for quotes:

$array = implode(', ', $array);

Answer 2

您犯了一个小错误：

 $array = $idFriend . ','; //There should be a period here.

Answer 3

Correct way is:

$arr = array();
while($row = mysql_fetch_array($result)){
  $idFriend = $row['idFriend'];
  $array[] = $idFriend;
}

// then implode that array using IN sql statement.
$query_friends = "SELECT * FROM whosout WHERE idPerson IN (implode(','$arr))";