PHP 8.3.4 Released!

pg_fetch_result

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_fetch_result从结果实例返回值

说明

pg_fetch_result(PgSql\Result $result, string|false|null $row, mixed $field): string|false|null
pg_fetch_result(PgSql\Result $result, mixed $field): string|false|null

pg_fetch_result() 返回 PgSql\Result 实例中特定行和字段(列)的值。

注意:

此函数过去称为 pg_result()

参数

result

PgSql\Result 实例,由 pg_query()pg_query_params() 或者 pg_execute()(等)返回。

row

要获取的结果中的行号。行从 0 向上编号。如果省略,则获取下一行。

field

表示要获取的字段(列)名的 string,否则为表示要获取的字段编号的 int。字段从 0 向上编号。

返回值

布尔值返回为 "t" 或 "f"。所有其它类型,包括数组,都以字符串形式返回,其格式与 psql 程序中的 PostgreSQL 默认方式相同。数据库 NULL 值作为 null 返回。

如果 row 超过集合中的行数或任何其他错误,则返回 false

更新日志

版本 说明
8.3.0 row 现在可为 null。
8.1.0 现在 result 参数接受 PgSql\Result 实例,之前接受 resource

示例

示例 #1 pg_fetch_result() 示例

<?php
$db
= pg_connect("dbname=users user=me") || die();

$res = pg_query($db, "SELECT 1 UNION ALL SELECT 2");

$val = pg_fetch_result($res, 1, 0);

echo
"First field in the second row is: ", $val, "\n";
?>

以上示例会输出:

First field in the second row is: 2

参见

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User Contributed Notes 5 notes

up
5
ElDiablo
5 years ago
Please note that a very old bug (#76548) has been fixed in 7.2.8.

Previously, pg_fetch_result did not fetch the next row if $row was omitted.
It is now well the case, so bad use of the function can now cause some bugs in your codes.
up
1
newby_AT_nobletec_DOT_com
21 years ago
Comment on boolean fields:

If you retrieve a boolean value from the PostgreSQL database, be aware that the value returned will be either the character 't' or the character 'f', not an integer. So, the statement

if (pg_fetch_result($rsRecords,0,'blnTrueFalseField')) {
echo "TRUE";
} else {
echo "FALSE";
}

will echo "TRUE" in either case (True or False stored in the field). In order to work as expected, do this instead:

if (pg_fetch_result($rsRecords,0,'blnTrueFalseField') == 't') {
echo "TRUE";
} else {
echo "FALSE";
}
up
2
Alan U. Kennington
17 years ago
See bug #33809 http://bugs.php.net/bug.php?id=33809
Whether this really is a bug or a feature is not clear.
However, it is probably best to always put your column names in extra quotes.

$res = pg_query(...);
$colname = pg_field_name($res, $j);
pg_fetch_result($res, $i, "\"$colname\"");
up
-2
Alan U Kennington
17 years ago
In order to use upper case in pg_fetch_result column names, it is apparently necessary to include explicit quotation marks.

Thus when I do this sort of thing:

$res = pg_query(...);
$ncols = pg_num_fields($res);
for ($j = 0; $j < $ncols; ++$j) {
$colname[$j] = pg_field_name($res, $j);
$name = htmlspecialchars($colname[$j]);
print("Column $j name = \"$name\"\n");
$value = htmlspecialchars(pg_fetch_result($res, 0, $colname[$j]));
print("Column \"{$colname[$j]}\" value = \"$value\"\n");
}

I get this sort of thing:

[....]
Warning: pg_fetch_result() [function.pg-fetch-result]: Bad column offset specified in /.../view.php on line 247
Column 8 name = "VEC index"
Column "VEC index" value = ""

But if I change the $value line to this:

$value = htmlspecialchars(pg_fetch_result($res, 0, "\"$colname[$j]\""));

I get this:

[...]
Column 8 name = "VEC index"
Column "VEC index" value[0] = "47"

In my opinion, pg_fetch_result(...) should use the quotes already. In other words, this may be a bug in the PHP postgres library. It does not seem to be a documented feature of pg_fetch_result() although the postgresql manual documents it under "SQL syntax", "Lexical structure".

PHP version 5.1.4.
psql version 8.1.4.
up
-3
Akbar
19 years ago
Use can use pg_fetch_result when getting a value (like a smallint as in this example) returned by your stored procedure

<?php
$pgConnection
= pg_connect("dbname=users user=me");

$userNameToCheckFor = "metal";

$result = pg_query($pgConnection, "SELECT howManyUsersHaveThisName('$userNameToCheckFor')");

$count = pg_fetch_result($result, 0, 'howManyUsersHaveThisName');

?>
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