Matching multiple paths with dynamic conditions

GSQL
1

Hi,

To explain my requirement, let’s take the following example.

Let there be 3 entities

  1. User

  2. Device

  3. Event

User - (used) - Device

User - (occurred) - Event

Now I want to get all users, device and event combinations for which some conditions are true. The query for this in Cypher is below

MATCH (u:User)-[occ:occurred]-(ev:Event), (u:User)-[ud:used]-(d:Device) WHERE

RETURN u,ev,d

This returns each combination of user, event and device for which conditions are true.

The conditions can be dynamic and can contain AND/OR grouping.

How can I achieve this in GSQL?

2

Hi Raghav,

Thanks for your question.

For dynamic condition evaluation please follow this link

https://docs.tigergraph.com/dev/gsql-ref/querying/operators-functions-and-expressions#dynamic-expressions-with-evaluate

To return each combination, we can store the vertex in a MaxAccum.

So, in the end, your query would look like this (pseudo code, I didn’t test it):

CREAT QUERY q1 (string cond1, string cond2) FOR GRAPH graph1 {

MaxAccum @event, @device;

users = {User.*};

users = select s from users:s-( occ:occurred )-:t

          where evaluate(cond1, "bool")

          accum s.@event += t;

users = select s from users:s-( ud:used )-:t

          where evaluate(cond2, "bool");

          accum s.@device += t;

print users;

}

Please be noted that evaluate() is slower than normal expressions. Also, another option for the dynamic condition is interpreted query.

https://docs.tigergraph.com/dev/gsql-ref/querying/query-operations#interpret-query

Thanks.

3

Hi Xinyu Chang,

Thanks for the reply.

CREAT QUERY q1 (string cond1, string cond2) FOR GRAPH graph1 {

MaxAccum @event, @device;

users = {User.*};

users = select s from users:s-( occ:occurred )-:t

          where evaluate(cond1, "bool")

          accum s.@event += t;

users = select s from users:s-( ud:used )-:t

          where evaluate(cond2, "bool");

          accum s.@device += t;

print users;

}

This query gives me users for which cond1 AND cond2 are true. what if I want where cond1 OR cond2 is true?

I will have additional entities like Event-(has)-EventDetails and my condition could be on any entity.

I may receive an expression, where conditions are not separated by paths, like

(Device.name == “one” OR Event.name == “event_1”) AND (Device.name == “two” OR EventDetails.location == “US”)

So how do I get users for which above is true?

I even thought of creating a pattern like

User:u1 - (used) - Device - (used) - User:u2 - (occurred)- Event:e-(occurred)-User:u3 Where u1.primary_id=u2.primary_id AND u2.primary_id=u3.primary_id and ( condition expression )

but the query throws an error.