PostgreSQL JSON arrow operators

[juliencorman]

Hello,

With the JSQL Parser Version 4.5, I encountered the two following issues when parsing PostgreSQL JSON functions in infix notation (the "arrow" operators).

The query
SELECT '{"key": "value"}'::json -> 'key' AS X
yields an exception
net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "->" "->".

This extends to all the combinations that I tried for the pattern
SELECT [leftOperand]::[datatype] [arrowSymbol] [rightOperand] AS X
where
[leftOperand] is a json object
[datatype] is one of {json, jsonb}
[arrowSymbol] is one of { ->, ->>, #>, #>>}
[rightOperand] is a positive integer, a quoted string or a an expression of the form '{a,b}'.

The query
SELECT Y::json -> 'key' AS X
is parsed.

As well as all the combinations that I tried for the above pattern, but where is a non-quoted string (aka a variable name).

The expression
Y::json -> 'key'
in this example is exposed as an instance of
net.sf.jsqlparser.expression.JSONExpression.

And the right operand ('key' in this example) is the first element of the list
net.sf.jsqlparser.expression.JSONExpression.idents.

However, this list idents has private access.
And looking at the source code, I could not find a way to retrieve its elements.
The class JSONExpression contains a getter method for idents, but the code has been commented out.

Thank you in advance for your help.

Kind regards,
Julien Corman

[manticore-projects]

SELECT '{"key": "value"}'::json -> 'key' AS X

fails because JSONExpression is currently defined for Column only (but not for an Expression).
Please refere to the source JSQLParser/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt:4175

[manticore-projects]

Greetings,

I have fixed that, although we can't make it work with a generic function:

-- won't work
SELECT myStringFunction(a, b, c)::json -> 'key' AS X

The parser will become way too slow and many performance related tests will fail.
Although Parameters and Sub-Queries are supported.

I have also exposed the Idents() and Operators(), no idea what happened there.

[juliencorman]

Great, thank you very much!

Kind regards,
Julien Corman

[manticore-projects]

Please wait for the PR #1676 to get accepted. This will close the Issue automatically.
In the meantime you can pull from that branch yourself and compile from source.
Only @wumpz can accept PRs.