pg_fetch_all_columns()

(PHP 5 >= 5.1.0, PHP 7)

Fetches all rows in a particular result column as an array

说明

pg_fetch_all_columns(resource $result[,int $column= 0]): array

pg_fetch_all_columns() returns an array that contains all rows(records)in a particular column of the result resource.

Note:此函数将 NULL 字段设置为 PHP NULL值。

参数

$result: PostgreSQL query result resource, returned by pg_query(),pg_query_params() or pg_execute()(among others).
$column: Column number, zero-based, to be retrieved from the result resource. Defaults to the first column if not specified.

返回值

An array with all values in the result column.

FALSE is returned if$columnis larger than the number of columns in the result, or on any other error.

范例

Example #1 pg_fetch_all_columns() example

<?php 
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
  echo "An error occurred.\n";
  exit;
}
$result = pg_query($conn, "SELECT title, name, address FROM authors");
if (!$result) {
  echo "An error occurred.\n";
  exit;
}
// Get an array of all author names
$arr = pg_fetch_all_columns($result, 1);
var_dump($arr);
?>

参见

pg_fetch_all()从结果中提取所有行作为一个数组

Unfortunate that pg_fetch_all_columns() doesn't support fetching a column by its name -- if you want to do that, you'll need to use pg_field_num() as an intermediary:
For example:
<?php
if ($foo)
 $cols = "email_address";
else
 $cols = "last_name, middle_init";
$result = pg_query("Select first_name, $info, birthday from users_table");
// Problem -- does column #2 refer to the 'birthday' or 'middle_init' field?
$array = pg_fetch_all_columns($result, 2);
// Won't work, must use a column number instead of its name
$array = pg_fetch_all_columns($result, 'birthday');
// Works
$array = pg_fetch_all_columns($result, pg_field_num($result, 'birthday'));
?>

pg_fetch_all_columns() returns array (empty array) even if the result set in empty (while pg_fetch_all() returns FALSE when the result set is empty)
<?
$result = pg_query("
  SELECT 'something'
  WHERE 1 = 2
");
var_dump( pg_fetch_all($result) ); // boolean false
var_dump( pg_fetch_all_columns($result) ); // array(0){}
?>

php 4 equivalent:
<?php 
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
 echo "An error occured.\n";
 exit;
}
$result = pg_query($conn, "SELECT title, name, address FROM authors");
if (!$result) {
 echo "An error occured.\n";
 exit;
}
// Get an array of all author names
$arr = array();
while ($line = pg_fetch_array($result)) {
 array_push($arr, $line['name']);
}
var_dump($arr);
?>