Rui Wang created CALCITE-3964:
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Summary: Support <data type> in DESCRIPTOR operator
Key: CALCITE-3964
URL: https://issues.apache.org/jira/browse/CALCITE-3964
Project: Calcite
Issue Type: Sub-task
Reporter: Rui Wang
Assignee: Rui Wang
>From SQL standard 2016
{code:sql}
8.15 <descriptor argument>
<descriptor argument> ::=
<descriptor value constructor>
<descriptor value constructor> ::=
DESCRIPTOR <left paren> <descriptor column list> <right paren>
<descriptor column list> ::=
<descriptor column specification>
[ { <comma> <descriptor column specification> }... ]
<descriptor column specification> ::=
<column name> [ <data type> ]
A <descriptor argument> is the keyword DESCRIPTOR followed by a parenthesized
list of column names; each column name may optionally have a data type. If
every column name has a data type, then the descriptor describes a row type. In
the examples, CSVreader and Pivot use descriptor arguments that are just lists
of column names; ExecR is an example that uses a descriptor to pass a complete
row type.
{code}
DESCRIPTOR can include an optional data type, which will enable type checking
in SQL validator. It is useful for streaming windowing: the windowing is
required to be applied on TIMESTAMP type, and we can rely on descriptor to do
type validation.
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