diff --git a/src/wp-includes/query.php b/src/wp-includes/query.php
index 3703428d95..44e9a5c242 100644
--- a/src/wp-includes/query.php
+++ b/src/wp-includes/query.php
@@ -2775,7 +2775,7 @@ class WP_Query {
 		}
 
 		// If a search pattern is specified, load the posts that match.
-		if ( ! empty( $q['s'] ) ) {
+		if ( strlen( $q['s'] ) ) {
 			$search = $this->parse_search( $q );
 		}
 
diff --git a/tests/phpunit/tests/query/search.php b/tests/phpunit/tests/query/search.php
index 5fe6d5e62a..c21787d090 100644
--- a/tests/phpunit/tests/query/search.php
+++ b/tests/phpunit/tests/query/search.php
@@ -137,4 +137,26 @@ class Tests_Query_Search extends WP_UnitTestCase {
 
 		$this->assertNotRegExp( '|ORDER BY \(CASE[^\)]+\)|', $q->request );
 	}
+
+	/**
+	 * @ticket 31025
+	 */
+	public function test_s_zero() {
+		$p1 = $this->factory->post->create( array(
+			'post_status' => 'publish',
+			'post_title' => '1',
+		) );
+
+		$p2 = $this->factory->post->create( array(
+			'post_status' => 'publish',
+			'post_title' => '0',
+		) );
+
+		$q = new WP_Query( array(
+			's' => '0',
+			'fields' => 'ids',
+		) );
+
+		$this->assertEqualSets( array( $p2 ), $q->posts );
+	}
 }