@Override
    public String getString(final int columnIndex) throws SQLException {
        return (String) ResultSetUtils.convertValue(mergeResultSet.getValue(columnIndex, String.class), String.class);
    }
@Test
    void assertGetStringWithColumnLabel() throws SQLException {
        when(mergeResultSet.getValue(1, String.class)).thenReturn("value");
        assertThat(shardingSphereResultSet.getString("label"), is("value"));
    }