Implement mysqli_fetch_column

UPGRADING

@@ -226,6 +226,9 @@ PHP 8.1 UPGRADE NOTES
   . Binding in execute has been added to mysqli prepared statements.
     Parameters can now be passed to mysqli_stmt::execute as an array.
     RFC: https://wiki.php.net/rfc/mysqli_bind_in_execute
+  . A new function has been added to mysqli_result called mysqli_fetch_column().
+    It allows for fetching single scalar values from the result set.
+    RFC: https://wiki.php.net/rfc/mysqli_fetch_column
 
 - PDO MySQL:
   . The PDO::MYSQL_ATTR_LOCAL_INFILE_DIRECTORY attribute has been added, which

ext/mysqli/mysqli.stub.php

@@ -426,6 +426,11 @@ public function fetch_object(string $class = "stdClass", array $constructor_args
      */
     public function fetch_row() {}
 
+    /**
+     * @alias mysqli_fetch_column
+     */
+    public function fetch_column(int $column = 0): null|int|float|string|false {}
+
     /**
      * @return bool
      * @alias mysqli_field_seek
@@ -664,6 +669,8 @@ function mysqli_fetch_object(mysqli_result $result, string $class = "stdClass",
 
 function mysqli_fetch_row(mysqli_result $result): array|null|false {}
 
+function mysqli_fetch_column(mysqli_result $result, int $column = 0): null|int|float|string|false {}
+
 function mysqli_field_count(mysqli $mysql): int {}
 
 function mysqli_field_seek(mysqli_result $result, int $index): bool {}

ext/mysqli/mysqli_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: b0232d18f570208d673ad7535ca60997e038acb8 */
+ * Stub hash: 42fdb807a547cfa3ba35bb2b8a4ee0f0d556a18c */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_mysqli_affected_rows, 0, 1, MAY_BE_LONG|MAY_BE_STRING)
 	ZEND_ARG_OBJ_INFO(0, mysql, mysqli, 0)
@@ -115,6 +115,11 @@ ZEND_END_ARG_INFO()
 
 #define arginfo_mysqli_fetch_row arginfo_mysqli_fetch_assoc
 
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_mysqli_fetch_column, 0, 1, MAY_BE_NULL|MAY_BE_LONG|MAY_BE_DOUBLE|MAY_BE_STRING|MAY_BE_FALSE)
+	ZEND_ARG_OBJ_INFO(0, result, mysqli_result, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, column, IS_LONG, 0, "0")
+ZEND_END_ARG_INFO()
+
 #define arginfo_mysqli_field_count arginfo_mysqli_errno
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_mysqli_field_seek, 0, 2, _IS_BOOL, 0)
@@ -609,6 +614,10 @@ ZEND_END_ARG_INFO()
 
 #define arginfo_class_mysqli_result_fetch_row arginfo_class_mysqli_character_set_name
 
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_class_mysqli_result_fetch_column, 0, 0, MAY_BE_NULL|MAY_BE_LONG|MAY_BE_DOUBLE|MAY_BE_STRING|MAY_BE_FALSE)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, column, IS_LONG, 0, "0")
+ZEND_END_ARG_INFO()
+
 #define arginfo_class_mysqli_result_field_seek arginfo_class_mysqli_result_fetch_field_direct
 
 #define arginfo_class_mysqli_result_free_result arginfo_class_mysqli_character_set_name
@@ -709,6 +718,7 @@ ZEND_FUNCTION(mysqli_fetch_array);
 ZEND_FUNCTION(mysqli_fetch_assoc);
 ZEND_FUNCTION(mysqli_fetch_object);
 ZEND_FUNCTION(mysqli_fetch_row);
+ZEND_FUNCTION(mysqli_fetch_column);
 ZEND_FUNCTION(mysqli_field_count);
 ZEND_FUNCTION(mysqli_field_seek);
 ZEND_FUNCTION(mysqli_field_tell);
@@ -833,6 +843,7 @@ static const zend_function_entry ext_functions[] = {
 	ZEND_FE(mysqli_fetch_assoc, arginfo_mysqli_fetch_assoc)
 	ZEND_FE(mysqli_fetch_object, arginfo_mysqli_fetch_object)
 	ZEND_FE(mysqli_fetch_row, arginfo_mysqli_fetch_row)
+	ZEND_FE(mysqli_fetch_column, arginfo_mysqli_fetch_column)
 	ZEND_FE(mysqli_field_count, arginfo_mysqli_field_count)
 	ZEND_FE(mysqli_field_seek, arginfo_mysqli_field_seek)
 	ZEND_FE(mysqli_field_tell, arginfo_mysqli_field_tell)
@@ -998,6 +1009,7 @@ static const zend_function_entry class_mysqli_result_methods[] = {
 	ZEND_ME_MAPPING(fetch_assoc, mysqli_fetch_assoc, arginfo_class_mysqli_result_fetch_assoc, ZEND_ACC_PUBLIC)
 	ZEND_ME_MAPPING(fetch_object, mysqli_fetch_object, arginfo_class_mysqli_result_fetch_object, ZEND_ACC_PUBLIC)
 	ZEND_ME_MAPPING(fetch_row, mysqli_fetch_row, arginfo_class_mysqli_result_fetch_row, ZEND_ACC_PUBLIC)
+	ZEND_ME_MAPPING(fetch_column, mysqli_fetch_column, arginfo_class_mysqli_result_fetch_column, ZEND_ACC_PUBLIC)
 	ZEND_ME_MAPPING(field_seek, mysqli_field_seek, arginfo_class_mysqli_result_field_seek, ZEND_ACC_PUBLIC)
 	ZEND_ME_MAPPING(free_result, mysqli_free_result, arginfo_class_mysqli_result_free_result, ZEND_ACC_PUBLIC)
 	ZEND_ME(mysqli_result, getIterator, arginfo_class_mysqli_result_getIterator, ZEND_ACC_PUBLIC)

ext/mysqli/mysqli_nonapi.c

@@ -436,6 +436,39 @@ PHP_FUNCTION(mysqli_fetch_assoc)
 }
 /* }}} */
 
+/* {{{ Fetch a column from the result row  */
+PHP_FUNCTION(mysqli_fetch_column)
+{
+	MYSQL_RES		*result;
+	zval			*mysql_result;
+	zval 			row_array;
+	zend_long		col_no = 0;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS(), getThis(), "O|l", &mysql_result, mysqli_result_class_entry, &col_no) == FAILURE) {
+		RETURN_THROWS();
+	}
+	MYSQLI_FETCH_RESOURCE(result, MYSQL_RES*, mysql_result, "mysqli_result", MYSQLI_STATUS_VALID);
+
+	if (col_no < 0) {
+		zend_argument_value_error(ERROR_ARG_POS(2), "must be greater than or equal to 0");
+		RETURN_THROWS();
+	}
+	if (col_no >= mysql_num_fields(result)) {
+		zend_argument_value_error(ERROR_ARG_POS(2), "must be less than the number of fields for this result set");
+		RETURN_THROWS();
+	}
+
+	php_mysqli_fetch_into_hash_aux(&row_array, result, MYSQLI_NUM);
+	if (Z_TYPE(row_array) != IS_ARRAY) {
+		zval_ptr_dtor_nogc(&row_array);
+		RETURN_FALSE;
+	}
+
+	ZVAL_COPY(return_value, zend_hash_index_find(Z_ARR(row_array), col_no));
+	zval_ptr_dtor_nogc(&row_array);
+}
+/* }}} */
+
 /* {{{ Fetches all result rows as an associative array, a numeric array, or both */
 PHP_FUNCTION(mysqli_fetch_all)
 {

ext/mysqli/tests/mysqli_class_mysqli_result_interface.phpt

@@ -35,6 +35,7 @@ require_once('skipifconnectfailure.inc');
         'fetch_fields'          => true,
         'fetch_object'          => true,
         'fetch_row'             => true,
+        'fetch_column'          => true,
         'field_seek'            => true,
         'free'                  => true,
         'free_result'           => true,

ext/mysqli/tests/mysqli_fetch_column.phpt

@@ -0,0 +1,143 @@
+--TEST--
+mysqli_fetch_column()
+--SKIPIF--
+<?php
+require_once 'skipif.inc';
+require_once 'skipifconnectfailure.inc';
+?>
+--FILE--
+<?php
+
+require_once "connect.inc";
+require 'table.inc';
+mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
+
+$res = mysqli_query($link, "SELECT id, label FROM test ORDER BY id LIMIT 1");
+
+print "[001]\n";
+var_dump(mysqli_fetch_column($res));
+
+print "[002]\n";
+var_dump(mysqli_fetch_column($res));
+
+
+$link->options(MYSQLI_OPT_INT_AND_FLOAT_NATIVE, true);
+
+$res = mysqli_query($link, "SELECT
+    1 AS a,
+    2 AS a
+");
+print "[003]\n";
+var_dump(mysqli_fetch_column($res, 0));
+
+$res = mysqli_query($link, "SELECT
+    1 AS a,
+    2 AS a
+");
+print "[004]\n";
+var_dump(mysqli_fetch_column($res, 1));
+
+$res = mysqli_query($link, "SELECT
+    1 AS a,
+    2 AS a,
+    3
+");
+print "[005]\n";
+var_dump(mysqli_fetch_column($res, 2));
+
+$res = mysqli_query($link, "SELECT
+    1 AS a,
+    2 AS a,
+    3,
+    NULL AS d
+");
+print "[006]\n";
+var_dump(mysqli_fetch_column($res, 3));
+
+$res = mysqli_query($link, "SELECT
+    1 AS a,
+    2 AS a,
+    3,
+    NULL AS d,
+    true AS e
+");
+print "[007]\n";
+var_dump(mysqli_fetch_column($res, 4));
+
+$res = mysqli_query($link, "SELECT
+    1.42 AS a
+");
+print "[008]\n";
+var_dump(mysqli_fetch_column($res, 0));
+
+$res = mysqli_query($link, "SELECT
+    1.42E0 AS a
+");
+print "[009]\n";
+var_dump(mysqli_fetch_column($res, 0));
+
+$res = mysqli_query($link, "SELECT id, label FROM test ORDER BY id LIMIT 1");
+print "[010]\n";
+try {
+    var_dump(mysqli_fetch_column($res, -1));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), \PHP_EOL;
+}
+
+$res = mysqli_query($link, "SELECT id, label FROM test ORDER BY id LIMIT 1");
+print "[011]\n";
+try {
+    var_dump(mysqli_fetch_column($res, 2));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), \PHP_EOL;
+}
+
+mysqli_free_result($res);
+try {
+	mysqli_fetch_column($res);
+} catch (Error $exception) {
+	echo $exception->getMessage() . "\n";
+}
+
+$res = $link->query("SELECT id, label FROM test ORDER BY id LIMIT 2");
+
+print "[012]\n";
+var_dump($res->fetch_column());
+
+print "[013]\n";
+var_dump($res->fetch_column(1));
+
+mysqli_close($link);
+?>
+--CLEAN--
+<?php
+require_once "clean_table.inc";
+?>
+--EXPECT--
+[001]
+string(1) "1"
+[002]
+bool(false)
+[003]
+int(1)
+[004]
+int(2)
+[005]
+int(3)
+[006]
+NULL
+[007]
+int(1)
+[008]
+string(4) "1.42"
+[009]
+float(1.42)
+[010]
+mysqli_fetch_column(): Argument #2 ($column) must be greater than or equal to 0
+[011]
+mysqli_fetch_column(): Argument #2 ($column) must be less than the number of fields for this result set
+mysqli_result object is already closed
+[012]
+int(1)
+[013]
+string(1) "b"