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https://issues.apache.org/jira/browse/CALCITE-7145?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18035682#comment-18035682
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Julian Hyde commented on CALCITE-7145:
--------------------------------------

Another thing to bear in mind when deducing effects (what we've been calling 
safety) is {*}strictness{*}. A function is said to be *strict* if it always 
evaluates all of its arguments. This is important for safety because if any of 
the arguments throws, so will the call to the function.

SQL's *case* operator is non-strict (aka lazy). The following expression does 
not throw even if x is zero:
{code:java}
case when x > 0 then x / y else 5 end{code}
When I chose the word *strong* to describe how functions propagate nulls, it 
was an allusion to strictness, because the propagation of nulls and propagation 
of errors tend to run parallel to each other.

> RexSimplify should not simplify IS NULL(10/0)
> ---------------------------------------------
>
>                 Key: CALCITE-7145
>                 URL: https://issues.apache.org/jira/browse/CALCITE-7145
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Thomas Rebele
>            Assignee: Thomas Rebele
>            Priority: Major
>              Labels: pull-request-available
>
> RexSimplify incorrectly simplifies {{IS NULL(10/0)}} to false and {{IS NOT 
> NULL(10,0)}} to true
> In other DBMS it's either the inverse (sqlite, MySQL, MariaDB), or they throw 
> an exception in both cases (Oracle, Postgres). The behavior was also 
> mentioned in a comment on CALCITE-3368.
> Is it right that throwing an exception during query execution is the expected 
> behavior according to the SQL standard?



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