DROP TABLE IF EXISTS merge1;
DROP TABLE IF EXISTS merge2;

CREATE TABLE IF NOT EXISTS merge1 (x UInt64) ENGINE = Merge(currentDatabase(), '^merge\\d$');
CREATE TABLE IF NOT EXISTS merge2 (x UInt64) ENGINE = Merge(currentDatabase(), '^merge\\d$');

SELECT * FROM merge1; -- { serverError 306 }
SELECT * FROM merge2; -- { serverError 306 }

DROP TABLE merge1;
DROP TABLE merge2;