AggregateFunction column in external table didn't work

[zhicwu]

Below is the code snippet in Java trying to use bitmap as a query parameter:

try (ClickHouseConnection conn = newConnection(new Properties());
        PreparedStatement stmt = conn.prepareStatement(
                "SELECT bitmapContains(my_bitmap, toUInt32(1)) as v1, bitmapContains(my_bitmap, toUInt32(2)) as v2 from ext_table")) {
    ClickHouseRequest<?> request = stmt.unwrap(ClickHouseRequest.class);
    request.addExternal(ClickHouseExternalTable.builder().name("ext_table")
            .columns("my_bitmap AggregateFunction(groupBitmap,UInt32)").format(ClickHouseFormat.RowBinary)
            .content(new ByteArrayInputStream(ClickHouseBitmap.wrap(1, 3, 5).toBytes())).build());
    ResultSet rs = stmt.executeQuery();
    Assert.assertTrue(rs.next());
    Assert.assertEquals(rs.getInt(1), 1);
    Assert.assertEquals(rs.getInt(2), 0);
    Assert.assertFalse(rs.next());
}

Unfortunately it didn't work because of below check. Is it just a parsing error should be fixed or it's a limitation of external table by design?

ClickHouse/src/Core/ExternalTable.cpp

Lines 57 to 61 in b7fb21e

	std::vector<std::string> vals;
	splitInto<' ', ','>(vals, argument, true);
	if (vals.size() % 2 != 0)
	throw Exception("Odd number of attributes in section structure: " + std::to_string(vals.size()), ErrorCodes::BAD_ARGUMENTS);

[zhicwu]

Workaround in JDBC:

try (ClickHouseConnection conn = newConnection(new Properties());
        PreparedStatement stmt = conn.prepareStatement(
                "SELECT bitmapContains(my_bitmap, toUInt32(1)) as v1, bitmapContains(my_bitmap, toUInt32(2)) as v2 from {tt 'ext_table'}")) {
    stmt.setObject(1, ClickHouseExternalTable.builder().name("ext_table")
            .columns("my_bitmap AggregateFunction(groupBitmap,UInt32)")
            .format(ClickHouseFormat.RowBinary) // optional as it's same as default
            .content(new ByteArrayInputStream(ClickHouseBitmap.wrap(1, 3, 5).toBytes()))
            .asTempTable() // necessary because of this parsing error
            .build());
    ResultSet rs = stmt.executeQuery();
    Assert.assertTrue(rs.next());
    Assert.assertEquals(rs.getInt(1), 1);
    Assert.assertEquals(rs.getInt(2), 0);
    Assert.assertFalse(rs.next());
}