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From "DOAN DuyHai (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-10783) Allow literal value as parameter of UDF & UDA
Date Sun, 29 Nov 2015 19:26:11 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-10783?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15031145#comment-15031145
] 

DOAN DuyHai commented on CASSANDRA-10783:
-----------------------------------------

 The type of the input literal is given in the definition of the UDF and at runtime, all you
need to do is to parse the input text with regards to the declared type. Why would you try
to match *101* as *varint* since you know the type must be an *int* ?

 I can understand that the input parser will try to *guess* for the best matching type but
isn't it possible to *force* the parser to match an exact type and throw an exception if matching
fails ?

> Allow literal value as parameter of UDF & UDA
> ---------------------------------------------
>
>                 Key: CASSANDRA-10783
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10783
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: CQL
>            Reporter: DOAN DuyHai
>            Assignee: Robert Stupp
>            Priority: Minor
>             Fix For: 3.x
>
>
> I have defined the following UDF
> {code:sql}
> CREATE OR REPLACE FUNCTION  maxOf(current int, testValue int) RETURNS NULL ON NULL INPUT

> RETURNS int 
> LANGUAGE java 
> AS  'return Math.max(current,testValue);'
> CREATE TABLE maxValue(id int primary key, val int);
> INSERT INTO maxValue(id, val) VALUES(1, 100);
> SELECT maxOf(val, 101) FROM maxValue WHERE id=1;
> {code}
> I got the following error message:
> {code}
> SyntaxException: <ErrorMessage code=2000 [Syntax error in CQL query] message="line
1:19 no viable alternative at input '101' (SELECT maxOf(val1, [101]...)">
> {code}
>  It would be nice to allow literal value as parameter of UDF and UDA too.
>  I was thinking about an use-case for an UDA groupBy() function where the end user can
*inject* at runtime a literal value to select which aggregation he want to display, something
similar to GROUP BY ... HAVING <filter clause>



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