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From "Bruno Dumon (JIRA)" <j...@apache.org>
Subject [jira] [Created] (PHOENIX-853) Support CAST(x as varchar(length)) syntax
Date Fri, 14 Mar 2014 12:54:42 GMT
Bruno Dumon created PHOENIX-853:
-----------------------------------

             Summary: Support CAST(x as varchar(length)) syntax
                 Key: PHOENIX-853
                 URL: https://issues.apache.org/jira/browse/PHOENIX-853
             Project: Phoenix
          Issue Type: Improvement
            Reporter: Bruno Dumon


I would like Phoenix to recognize casts to varchars that specify lengths, e.g. cast(x as varchar(10)).
It is not an immediate goal to enforce the length, but at least to recongize the syntax.

(the reason I'm running into this is because I have sql generated by Optiq which uses these
kinds of constructs)

I can easily hack the grammar to add this to the CAST grammar, but then I realize that the
data type specification one can put in a cast is the same as what you can put in a column
definition. Therefore, it would make more sense to introduce a separate rule to parse the
data type and reuse that in the cast and column_def rules.

For arrays, the specification is currently not consistent:
 * in column_def it is: ar=ARRAY? (lsq=LSQUARE (a=NUMBER)? RSQUARE)?
 * in casts it is: ar=(ARRAY | (LSQUARE RSQUARE))? RPAREN

I assume this is not on purpose and can be aligned.

So in summary, what I'd like to do:
 * introduce some object to hold the data type information, e.g. "DataTypeDef", which splits
of the pure data type parts from ColumnDef, ColumnDef would then contain a DataTypeDef
 * introduce a separate parser rule to match the data type specification, and which returns
this new DataTypeDef object
 * reuse this parser rule in the column_def and cast rules
 * functionally, casts would stay the same for now

Alternatively, I can just add "(LPAREN l=NUMBER (COMMA s=NUMBER)? RPAREN)?" to the cast rule
and be done with it.

WDYT?



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