Thread: JSON path wild cards?

Is there a way to specify a wild card in a json path?

For example I have the following json doc:

[ {“a”:1,”b”: [ { “x”: 7,”y”:8,”z”:9} ] },  {“a”:2,”b”: [ { “x”: 4,”y”:5,”z”:6} ] }, … ]

How do I write a select clause that can return the values for all b x values something like [{b:x}] that would return
allthe b:x values in the array? e.g. 7 and 4 ...  

Also is there a definition of the syntax of a proper json path for use in postgres?

Thanks,  weirdly I just stumbled on the idea when your reply came in, of using jsonb_array_elements function wrapped in
aCTE that uses the containment operator within the CTE to select just the json docs I want and then I can select the
specificjson key values from each jsonb row/object returned by the CTE.  Basically  the same thing as a for each or
wildcard and it’s super fast with the jsonb indexing. 

e.g

WITH jsd AS
(
    SELECT jsonb_array_elements([ {“a”:1,”b”: [ { “x”: 7,”y”:8,”z”:9} ] },  {“a”:2,”b”: [ { “x”: 4,”y”:5,”z”:6} ] } ])
ASae  
)
SELECT ae->’b’ FROM jsd;

Note: In my real world problem I have WHERE clause in the CTW statement using the @> operator so the CTE can be more
selectiveagainst the entire set of jsonb doc’s in the containing table. 

>
> On Nov 23, 2015, at 10:39 PM, Dennis <dennisr@visi.com> wrote:
>
> Is there a way to specify a wild card in a json path?
>
> For example I have the following json doc:
>
> [ {“a”:1,”b”: [ { “x”: 7,”y”:8,”z”:9} ] },  {“a”:2,”b”: [ { “x”: 4,”y”:5,”z”:6} ] }, … ]
>
> How do I write a select clause that can return the values for all b x values something like [{b:x}] that would return
allthe b:x values in the array? e.g. 7 and 4 ...  
>
> Also is there a definition of the syntax of a proper json path for use in postgres?
>
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