运行两个连续的while循环时的光标位置问题

Question

How does one "reset" pg_fetch_row cursor position to start with the first row in case you want to run through the same result set twice?

$result = pg_query($conn, "SELECT author, email FROM authors");
if (!$result) {
  echo "An error occurred.\n";
  exit;
}

while ($row = pg_fetch_row($result)) {
  echo "Author: $row[0]  E-mail: $row[1]";
  echo "<br />\n";
}

while ($row = pg_fetch_row($result)) {     // <---- THIS WILL ALWAYS SHOW NOTHING AS IT DOESN'T START FROM the first row (0)
  echo "Author: $row[0]  E-mail: $row[1]";
  echo "<br />\n";
}

Answer 1

Use pg_result_seek() http://php.net/manual/en/function.pg-result-seek.php

$result = pg_query($conn, "SELECT author, email FROM authors");
if (!$result) {
  echo "An error occurred.\n";
  exit;
}

while ($row = pg_fetch_row($result)) {
  echo "Author: $row[0]  E-mail: $row[1]";
  echo "<br />\n";
}

pg_result_seek($result, 0);

while ($row = pg_fetch_row($result)) {
  echo "Author: $row[0]  E-mail: $row[1]";
  echo "<br />\n";
}