unhexAsBitmap

[Gotham-Joker]

Converting a hexadecimal string to a bitmap value.

I am aware that I cannot execute a query with a bitmap parameter using JDBC. For example, if I have the following query using JDBC: "select bitmapToArray(?) as res", is there any solution to pass a variable of type bitmap to the placeholder '?'?
I understand that I can use "select bitmapToArray(bitmapBuild([1,2,3....]))" instead, but when the bitmap is large, it does not work well for JDBC.
If there is no solution available, how about providing a function 'unhexAsBitmap(?)'?

This function would convert a hexadecimal parameter to a bitmap value.

[den-crane]

Hm, why do you need select bitmap ? Is it a part of an insert select?

JDBC supports bitmaps https://github.com/search?q=repo%3AClickHouse%2Fclickhouse-java%20ClickHouseBitmap&type=code

You can use input function or external data (jdbc supports external data) https://clickhouse.com/docs/en/engines/table-engines/special/external-data

And such function already exists unhex

select hex(bitmapBuild([1,2,3]));
┌─hex(bitmapBuild([1, 2, 3]))─┐
│ 0003010203                  │
└─────────────────────────────┘

select bitmapToArray(cast(unhex('0003010203'), 'AggregateFunction(groupBitmap, UInt8)'));
┌─bitmapToArray(CAST(unhex('0003010203'), 'AggregateFunction(groupBitmap, UInt8)'))─┐
│ [1,2,3]                                                                           │
└───────────────────────────────────────────────────────────────────────────────────┘

[Gotham-Joker]

I require the 'select bitmap' functionality because the bitmap value is evaluated by my Java program. Subsequently, I utilize it to filter data from the 'clickhouse' table, rather than using an insert select scenario.
In conclusion,thank you for providing solution,it is very useful.