pg_fetch_result

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

pg_fetch_result — Returns values from a result instance

Descripción

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() returns the value of a particular row and field (column) in an PgSql\Result instance.

Nota:
This function used to be called pg_result().

Parámetros

result: An PgSql\Result instance, returned by pg_query(), pg_query_params() or pg_execute()(among others).
row: Row number in result to fetch. Rows are numbered from 0 upwards. If omitted, next row is fetched.
field: A string representing the name of the field (column) to fetch, otherwise an int representing the field number to fetch. Fields are numbered from 0 upwards.

Valores devueltos

Boolean is returned as "t" or "f". All other types, including arrays are returned as strings formatted in the same default PostgreSQL manner that you would see in the psql program. Database NULL values are returned as null.

false is returned if row exceeds the number of rows in the set, or on any other error.

Historial de cambios

Versión	Descripción
8.3.0	`row` is now nullable.
8.1.0	The `result` parameter expects an PgSql\Result instance now; previously, a recurso was expected.

Ejemplos

Ejemplo #1 pg_fetch_result() example

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

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

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

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

El resultado del ejemplo sería:

First field in the second row is: 2

Ver también

pg_query() - Ejecutar una consulta
pg_fetch_array() - Fetch a row as an array

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User Contributed Notes 5 notes

down

ElDiablo ¶

6 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.

down

newby_AT_nobletec_DOT_com ¶

22 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";
     }

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Alan U. Kennington ¶

18 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\"");

down

-2

Alan U Kennington ¶

18 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.

down

-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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