my-ship-it commented on PR #1187:
URL: https://github.com/apache/cloudberry/pull/1187#issuecomment-3003796481
Just tried:
```
-- 状态转换函数：处理单个输入值并更新状态
CREATE OR REPLACE FUNCTION avg_trans_fn(
state numeric[], -- 当前状态：[sum, count]
next_val numeric -- 新输入值
) RETURNS numeric[] AS $$
BEGIN
IF next_val IS NOT NULL THEN
state[1] := COALESCE(state[1], 0) + next_val;
state[2] := COALESCE(state[2], 0) + 1;
END IF;
RETURN state;
END;
$$ LANGUAGE plpgsql;
-- 合并函数：合并两个部分聚合状态
CREATE OR REPLACE FUNCTION avg_combine_fn(
state1 numeric[],
state2 numeric[]
) RETURNS numeric[] AS $$
BEGIN
IF state1 IS NULL THEN
RETURN state2;
ELSIF state2 IS NULL THEN
RETURN state1;
ELSE
RETURN ARRAY[state1[1] + state2[1], state1[2] + state2[2]];
END IF;
END;
$$ LANGUAGE plpgsql;
-- 最终函数：从状态计算最终结果
CREATE OR REPLACE FUNCTION avg_final_fn(
state numeric[]
) RETURNS numeric AS $$
BEGIN
IF state[2] = 0 THEN
RETURN NULL;
ELSE
RETURN state[1] / state[2];
END IF;
END;
$$ LANGUAGE plpgsql;
CREATE AGGREGATE my_avg(numeric) (
sfunc = avg_trans_fn, -- 状态转换函数
stype = numeric[], -- 状态类型
combinefunc = avg_combine_fn, -- 合并函数
finalfunc = avg_final_fn, -- 最终计算函数
initcond = '{0,0}' -- 初始状态
);
CREATE TABLE tbl1(v1 int, v2 numeric);
CREATE TABLE tbl2(v1 int, v2 numeric);
```
The agg pushdown doesn't work in ORCA but works in postgres Postgres query
optimizer.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
