Bigquery: Added sample to get large dataset with legacy SQL (GoogleCloudPlatform#1592)

* Bigquery: Added sample to query dataset with legacy SQL

Author: saranshdhingra

bigquery/api/src/query_legacy.php

@@ -0,0 +1,52 @@
+
+/**
+ * Copyright 2022 Google LLC.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * For instructions on how to run the full sample:
+ *
+ * @see https://github.com/GoogleCloudPlatform/php-docs-samples/tree/master/bigquery/api/README.md
+ */
+
+// Include Google Cloud dependendencies using Composer
+require_once __DIR__ . '/../vendor/autoload.php';
+
+if (count($argv) != 2) {
+    return printf("Usage: php %s PROJECT_ID\n", __FILE__);
+}
+list($_, $projectId) = $argv;
+
+// [START bigquery_query_legacy]
+use Google\Cloud\BigQuery\BigQueryClient;
+
+$query = 'SELECT corpus FROM [bigquery-public-data:samples.shakespeare] GROUP BY corpus';
+
+$bigQuery = new BigQueryClient([
+    'projectId' => $projectId,
+]);
+$jobConfig = $bigQuery->query($query)->useLegacySql(true);
+
+$queryResults = $bigQuery->runQuery($jobConfig);
+
+$i = 0;
+foreach ($queryResults as $row) {
+    printf('--- Row %s ---' . PHP_EOL, ++$i);
+    foreach ($row as $column => $value) {
+        printf('%s: %s' . PHP_EOL, $column, json_encode($value));
+    }
+}
+printf('Found %s row(s)' . PHP_EOL, $i);
+// [END bigquery_query_legacy]

bigquery/api/test/bigqueryTest.php

@@ -287,6 +287,14 @@ public function testRunQueryAsJob()
         $this->assertStringContainsString('Found 1 row(s)', $output);
     }
 
+    public function testQueryLegacy()
+    {
+        $output = $this->runSnippet('query_legacy');
+        $this->assertStringContainsString('tempest', $output);
+        $this->assertStringContainsString('kinghenryviii', $output);
+        $this->assertStringContainsString('Found 42 row(s)', $output);
+    }
+
     private function runSnippet($sampleName, $params = [])
     {
         $argv = array_merge([0, self::$projectId], $params);