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Benjamin Lerer commented on CASSANDRA-11935:
--------------------------------------------
{quote}
That said, I "think" CASSANDRA-11946 also help here, assuming we restrict
functions overloads by return type first. In that case, we'd create overloads
with same argument types but different return type (so {{tinyint add(tinyint,
tinyint)}}, {{int add(tinyint, tinyint)}}, {{bigint add(tinyint, tinyint)}},
etc...) and {{i = 100 + 50}} would use the proper one.
{quote}
It would work for {{i = 100 + 50}} but not for {{SELECT 100 + 50}} where we
will get an error like: {{Ambiguous '+' operation: use type casts to
disambiguate}}.
If we do not overload functions with different return types but still use the
return type to eliminates some of the functions, in the case of {{c = 1 + 1}},
where c is a {{smallint}}, we end up with 3 possible functions: {{smallint
add(tinyint, smallint)}}, {{smallint add(tinyint, smallint)}} and {{smallint
add(smallint, smallint)}}.
In such a case, I believe that we should just pick the operation with the same
argument types than the return type.
The only corner case (if I did not miss anything) would be with bind markers.
For something like: {{c = 1 + ?}} I believe that we should force the user to
use a {{type hint}} as the fact that a {{smallint}} is expected is not obvious.
For the {{preferedType}} I still believe that we should stop at {{int}} for
integer to minimize the risk of overflow issues in the selection part.
> Add support for arithmetic operators
> ------------------------------------
>
> Key: CASSANDRA-11935
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11935
> Project: Cassandra
> Issue Type: Sub-task
> Components: CQL
> Reporter: Benjamin Lerer
> Assignee: Benjamin Lerer
> Fix For: 3.x
>
>
> The goal of this ticket is to add support for arithmetic operators:
> * {{-}}: Change the sign of the argument
> * {{+}}: Addition operator
> * {{-}}: Minus operator
> * {{*}}: Multiplication operator
> * {{/}}: Division operator
> * {{%}}: Modulo operator
> This ticket we should focus on adding operator only for numeric types to keep
> the scope as small as possible. Dates and string operations will be adressed
> in follow up tickets.
> The operation precedence should be:
> # {{*}}, {{/}}, {{%}}
> # {{+}}, {{-}}
> Some implicit data conversion should be performed when operations are
> performed on different types (e.g. double + int).
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