Add the aggregate functions `BIT_AND` / `BIT_OR` / `BOOL_AND`

[Leomrlin]

What & why

The aggregate folder udf/table/agg/ has 20 functions (Count, Sum*, Avg*,
Percentile*, …) but no bitwise aggregates (BIT_AND / BIT_OR) or boolean
aggregate (BOOL_AND — true only if every value is true). Aggregates are a step
up from scalar functions: you implement an Accumulator and, crucially, a
correct distributed merge. This is the issue that teaches you how distributed
aggregation actually works.

聚合函数目录已有 20 个,但缺位运算聚合 BIT_AND/BIT_OR 和布尔聚合 BOOL_AND
(全为真才为真)。聚合函数比标量函数稍难——要实现 Accumulator 并写对分布式 merge。
做完这题,你就真正理解了分布式聚合是怎么回事。

The task

• bit_and(x) / bit_or(x) → bitwise AND/OR over a column of integers
• bool_and(b) → whether a column of booleans is all true

Where to look

1. udf/table/agg/Count.java is the simplest UDAF template (it has the inner
   Accumulator class). Implement the five methods:
   createAccumulator / accumulate / merge / resetAccumulator / getValue.
2. The Accumulator must implement Serializable (it gets serialized across the cluster).
3. Register in BuildInSqlFunctionTable.java.
4. Build multi-row test data; ideally exercise a multi-partition merge.

Done when

• Three UDAFs implemented, with correct merge logic (this is what makes distributed results correct)
• Accumulator is serializable
• Empty-input / all-null return values are defined
• Tests pass, including multi-row aggregation

[ailisilob]

can u assign this to me, I would like to work on this

[huangguasky]

Hi, I'd like to work on this issue. Could you please assign it to me?

I plan to implement BIT_AND / BIT_OR for integer inputs and BOOL_AND for boolean inputs, including serializable accumulators, merge logic, registration, and tests.