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https://issues.apache.org/jira/browse/CALCITE-6971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhen Chen updated CALCITE-6971:
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Summary: Calculation accuracy loss after agg over to case when (was:
Calculation accuracy loss after using PROJECT_OVER_SUM_TO_SUM0_RULE)
> Calculation accuracy loss after agg over to case when
> -----------------------------------------------------
>
> Key: CALCITE-6971
> URL: https://issues.apache.org/jira/browse/CALCITE-6971
> Project: Calcite
> Issue Type: Bug
> Reporter: Zhen Chen
> Priority: Major
>
> As testWindowedSum0BecomesCoalesce the sql
>
> {code:java}
> select
> AVG("net_weight") OVER (order by "product_id" rows 3 preceding)
> from "product"; {code}
> can be convert to
>
>
> {code:java}
> SELECT CASE
> WHEN COUNT("net_weight") OVER (ORDER BY "product_id" ROWS BETWEEN 3
> PRECEDING AND CURRENT ROW) > 0 THEN COALESCE(SUM("net_weight") OVER (ORDER BY
> "product_id" ROWS BETWEEN 3 PRECEDING AND CURRENT ROW), 0)
> ELSE NULL
> END / COUNT("net_weight") OVER (ORDER BY "product_id" ROWS BETWEEN 3
> PRECEDING AND CURRENT ROW)
> FROM "product"; {code}
> But the execution results are different in pgsql.
> {code:java}
> create table product (product_id int, net_weight int);
> insert into product values (1,1),(1,2),(2,1),(2,2),(null,1),(1,null),(null,
> null); {code}
> Result is
> {code:java}
> -- first sql
> avg
> ------------------------
> 1.00000000000000000000
> 1.00000000000000000000
> 1.5000000000000000
> 1.6666666666666667
> 1.6666666666666667
> 1.5000000000000000
> 1.3333333333333333
> (7 rows)
> -- second sql
> ?column?
> ----------
> 1
> 1
> 1
> 1
> 1
> 1
> 1
> (7 rows){code}
>
>
>
>
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