public static ShowResultSet execute(ShowStmt statement, ConnectContext context) {
        return GlobalStateMgr.getCurrentState().getShowExecutor().showExecutorVisitor.visit(statement, context);
    }
@Test(expected = SemanticException.class)
    public void testShowCreateNoDb() {
        ctx.setGlobalStateMgr(globalStateMgr);
        ctx.setQualifiedUser("testUser");

        ShowCreateDbStmt stmt = new ShowCreateDbStmt("emptyDb");

        ShowResultSet resultSet = ShowExecutor.execute(stmt, ctx);

        Assert.fail("No exception throws.");
    }