MySQL and PHP
Copyright 1997-2021 the PHP Documentation Group.
A MySQL result set contains metadata. The metadata describes the
columns found in the result set. All metadata sent by MySQL is
accessible through the mysqli
interface. The
extension performs no or negligible changes to the information
it receives. Differences between MySQL server versions are not
aligned.
Meta data is access through the
mysqli_result
interface.
Example 3.28 Accessing result set meta data
<?php $mysqli = new mysqli("example.com", "user", "password", "database"); if ($mysqli->connect_errno) { echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error; } $res = $mysqli->query("SELECT 1 AS _one, 'Hello' AS _two FROM DUAL"); var_dump($res->fetch_fields()); ?>
The above example will output:
array(2) { [0]=> object(stdClass)#3 (13) { ["name"]=> string(4) "_one" ["orgname"]=> string(0) "" ["table"]=> string(0) "" ["orgtable"]=> string(0) "" ["def"]=> string(0) "" ["db"]=> string(0) "" ["catalog"]=> string(3) "def" ["max_length"]=> int(1) ["length"]=> int(1) ["charsetnr"]=> int(63) ["flags"]=> int(32897) ["type"]=> int(8) ["decimals"]=> int(0) } [1]=> object(stdClass)#4 (13) { ["name"]=> string(4) "_two" ["orgname"]=> string(0) "" ["table"]=> string(0) "" ["orgtable"]=> string(0) "" ["def"]=> string(0) "" ["db"]=> string(0) "" ["catalog"]=> string(3) "def" ["max_length"]=> int(5) ["length"]=> int(5) ["charsetnr"]=> int(8) ["flags"]=> int(1) ["type"]=> int(253) ["decimals"]=> int(31) } }
Prepared statements
Meta data of result sets created using prepared statements are
accessed the same way. A suitable
mysqli_result
handle is returned by
mysqli_stmt_result_metadata
.
Example 3.29 Prepared statements metadata
<?php $stmt = $mysqli->prepare("SELECT 1 AS _one, 'Hello' AS _two FROM DUAL"); $stmt->execute(); $res = $stmt->result_metadata(); var_dump($res->fetch_fields()); ?>
See also
mysqli::query
|
mysqli_result::fetch_fields
|