@Override
    public String getString(final int columnIndex) throws SQLException {
        return (String) ResultSetUtils.convertValue(mergeResultSet.getValue(columnIndex, String.class), String.class);
    }
@Test
    void assertGetStringWithColumnIndex() throws SQLException {
        when(mergeResultSet.getValue(1, String.class)).thenReturn("value");
        LocalDateTime tempTime = LocalDateTime.of(2022, 12, 14, 0, 0);
        when(mergeResultSet.getValue(2, String.class)).thenReturn(tempTime);
        when(mergeResultSet.getValue(3, String.class)).thenReturn(Timestamp.valueOf(tempTime));
        assertThat(shardingSphereResultSet.getString(1), is("value"));
        assertThat(shardingSphereResultSet.getString(2), is("2022-12-14T00:00"));
        assertThat(shardingSphereResultSet.getString(3), is("2022-12-14 00:00:00.0"));
    }