php - PDO can I reuse the same Statement Handle for multiple queries? -

i using pdo access data base , looping using 2 while loops fetch @ same time, seen below:

$dbh = new pdo('mysql:host=localhost;dbname=database;charset=utf8',$dblogin,$dbpass); $sql = 'select * table'; $sth = $dbh->prepare($sql); $sth->execute();  while ($bm_table = $sth->fetch(pdo::fetch_assoc)) {  //sql query $sql1 = 'query here'; $sth1 = $dbh->prepare($sql1); $sth1->execute();  //loops through using different handle, if used sth again? while ($row = $sth1->fetch(pdo::fetch_assoc)) {     somefunction($bm_table,$row);  } } 

as can see above using different statement handle (sth, sth1 etc.) necessary? or can use 1 statement handle everything. reason have used multiple handles $bm_table value uses sth, still in use while fetching $row wouldn't change value of $bm_table or stop fetch working? how handles pdo work? when in case have 2 simultaneous fetch loops running @ same time using same pdo connection.

so main thing looking here if have 2 statements running simultaneously important used different handles? can continue use same connection?

thanks,

$sth , sth1 not statement handles, they're php variables. can reassign variable if no longer need old value. in case of code, still need old value.

if assign $sth inside outer loop handle returned second prepare() call, when gets top of loop , re-executes $sth->fetch() test, try fetch second query, not first one. end outer loop because rows have been read.

you can reuse statement handle repetitions of same query. useful when query has parameters:

$stmt = $dbh->prepare("select * tablename id = :id"); $stmt->bindparam(':id', $id); foreach ($id_array $id) {     $stmt->execute();     $row = $stmt->fetch();     // stuff $row }