Index: src/wp-includes/class-wp-meta-query.php
===================================================================
--- src/wp-includes/class-wp-meta-query.php	(revision 42215)
+++ src/wp-includes/class-wp-meta-query.php	(working copy)
@@ -95,6 +95,13 @@
 	protected $has_or_relation = false;
 
 	/**
+	 * The default meta table alias.
+	 *
+	 * @var string
+	 */
+	protected $default_meta_table_alias = 'mt';
+
+	/**
 	 * Constructor.
 	 *
 	 * @since 3.2.0
@@ -511,7 +518,7 @@
 		$alias = $this->find_compatible_table_alias( $clause, $parent_query );
 		if ( false === $alias ) {
 			$i = count( $this->table_aliases );
-			$alias = $i ? 'mt' . $i : $this->meta_table;
+			$alias = $i ? $this->default_meta_table_alias . $i : $this->meta_table;
 
 			// JOIN clauses for NOT EXISTS have their own syntax.
 			if ( 'NOT EXISTS' === $meta_compare ) {
@@ -727,4 +734,15 @@
 	public function has_or_relation() {
 		return $this->has_or_relation;
 	}
+
+	/**
+	 * Sets default meta table alias.
+	 *
+	 * @param string $default_meta_table_alias The default meta table alias.
+	 *
+	 * @return void
+	 */
+	public function set_default_meta_table_alias( $default_meta_table_alias ) {
+		$this->default_meta_table_alias = $default_meta_table_alias;
+	}
 }
Index: tests/phpunit/tests/meta/query.php
===================================================================
--- tests/phpunit/tests/meta/query.php	(revision 42215)
+++ tests/phpunit/tests/meta/query.php	(working copy)
@@ -884,4 +884,29 @@
 
 		$this->assertTrue( $q->has_or_relation() );
 	}
+
+	/**
+	 * Test that a custom default_meta_table_alias can be set.
+	 * @ticket 41266
+	 */
+	public function test_set_default_meta_table_alias() {
+		global $wpdb;
+
+		$query = new WP_Meta_Query();
+
+		$query->set_default_meta_table_alias( 'myalias' );
+
+		$the_complex_query[ 'meta_query' ] = array(
+			array( 'key' => 'my_first_key', 'value' => 'my_amazing_value' ),
+			array( 'key' => 'my_second_key', 'compare' => 'NOT EXISTS' ),
+			array( 'key' => 'my_third_key', 'value' => array(), 'compare' => 'IN' ),
+		);
+
+		$query->parse_query_vars( $the_complex_query );
+
+		$sql = $query->get_sql( 'post', $wpdb->posts, 'ID', $this );
+
+		$this->assertContains( 'AS myalias1', $sql[ 'join' ] );
+		$this->assertContains( 'AS myalias2', $sql[ 'join' ] );
+	}
 }