Ok thank you ! It works very well !
Le mardi 28 novembre 2017 21:39:22 UTC+1, Michael Hunger a écrit :
>
> MATCH (p:Person) WHERE p.name =~ '(?i).test.*'
> WITH COLLECT(DISTINCT {name: p.name}) as persons
> OPTIONAL MATCH (pla:Place) WHERE pla.name =~ '(?i).*test.*'
> RETURN persons, [x IN COLLECT(DISTINCT pla) | {name: x.name}] as places
>
> On Tue, Nov 28, 2017 at 11:56 AM, <[email protected] <javascript:>> wrote:
>
>> OK thank you.
>>
>> Actually, the null value is "added" when I use COLLECT. So I can't really
>> filter the null values.
>> If I filter before the collect there is no null value yet. And if I
>> filter on the collect result, there is no null item, because an object is
>> create with the name property which is null.
>> It cannot return an empty array for one COLLECT and have results in the
>> other... I don't understand why.
>>
>> I do the following workaround using UNION ALL:
>>
>> MATCH (p:Person) WHERE p.name =~ '(?i).*test.*'
>> return {persons: COLLECT(DISTINCT {name: p.name})} as results
>> UNION ALL MATCH (pla:Place) WHERE pla.name =~ '(?i).*test.*'
>> return {places: COLLECT(DISTINCT {name: pla.name})} as results
>>
>> I get this:
>>
>> ╒═════════════════════════════════════════════════════════════╕
>> │"results" │
>> ╞═════════════════════════════════════════════════════════════╡
>> │{"persons":[]} │
>> ├─────────────────────────────────────────────────────────────┤
>> │{"places":[{"name":"Test 1"},{"name":"Test 2"}]} │
>> └─────────────────────────────────────────────────────────────┘
>>
>>
>>
>> I am surprised there is no way to have two separated keys "persons" and
>> "places" which contains an array of objects like this:
>>
>> ╒═══════════════╤═════════════════════════════════════════════════╕
>> │"persons" │"places" │
>> ╞═══════════════╪═════════════════════════════════════════════════╡
>> │[ ] │[{"name":"Test 1"},{"name":"Test 2"}] │
>> └───────────────┴─────────────────────────────────────────────────┘
>>
>>
>> It adds this object in "persons" if I use OPTIONAL:
>>
>> {"name":null}
>>
>>
>> Without OPTIONAL, "places" is empty.
>>
>> Any idea to achieve this ?
>>
>>
>> Thank you.
>>
>> Le mardi 28 novembre 2017 09:44:44 UTC+1, Michael Hunger a écrit :
>>>
>>> WITH a UNION as those 2 queries are unrelated.
>>>
>>> If you use your approach you also compute a cross product.
>>> It would be better to aggregate first
>>>
>>> MATCH (p:Person) WHERE p.name =~ '(?i).test.*'
>>> WITH COLLECT(DISTINCT {name: p.name}) as persons
>>> OPTIONAL MATCH (pla:Place) WHERE pla.name =~ '(?i).*test.*'
>>> return persons, COLLECT(DISTINCT {name: pla.name}) as places
>>>
>>> Empty matches only return any data rows when you return a single
>>> aggregation, like your collect, otherwise they will just result in no rows.
>>> (You can just filter out the null value from the optional match)
>>>
>>> In general aggregation functions skip null values.
>>>
>>> The regular expression match is not very efficient, as it has to scan
>>> the full label.
>>>
>>>
>>> On Mon, Nov 27, 2017 at 10:01 AM, <[email protected]> wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm trying to find nodes matching a text in their name.
>>>>
>>>> For one node I do :
>>>>
>>>> MATCH (p:Person) WHERE p.name =~ '(?i).test.*'
>>>> WITH p, {name: p.name} as person
>>>> return COLLECT(DISTINCT person) as persons
>>>>
>>>> It works well.
>>>>
>>>>
>>>> But if I try for two nodes :
>>>>
>>>> MATCH (p:Person) WHERE p.name =~ '(?i).test.*'
>>>> WITH p, {name: p.name} as person
>>>> MATCH (pla:Place) WHERE pla.name =~ '(?i).*test.*'
>>>> WITH person, {name: pla.name} as place
>>>> return COLLECT(DISTINCT person) as persons, COLLECT(DISTINCT place) as
>>>> places
>>>>
>>>> If the first MATCH returns nothing the the entire query result is empty
>>>> even if the the second should return results.
>>>>
>>>>
>>>> I tried to add OPTIONAL, the result is not empty, the MATCH returns
>>>> expected objects but I get an object with name null for the MATCH which
>>>> should be empty :
>>>>
>>>> [
>>>> {
>>>> "name": null
>>>> }
>>>> ]
>>>>
>>>>
>>>>
>>>> How can I get the results for the MATCH which should has results and
>>>> get an empty array for the one which should not have result ?
>>>>
>>>> Thank you.
>>>>
>>>> Regards,
>>>> Clément
>>>>
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>>>
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