14.10.5.3 Creating a Subgraph from PGQL Result Set

A subgraph can be obtained from a PGQL result set using result set filters.

You can create a subgraph from a result set vertex filter, as shown in the following code:

• JShell
• Java

// Evaluates query on graph g to obtain result set
opg4j> var resultSet = g.queryPgql("SELECT x FROM MATCH (x) WHERE x.age > 24")
// Define a filter on the result set for the column "x"
opg4j> var resultSetVertexFilter = VertexFilter.fromPgqlResultSet(resultSet, "x")
// Create a subgraph of g containing the matched vertices in the resultSet and the edges that connect them if any.
opg4j> var newGraph = g.filter(resultSetVertexFilter)

// Evaluates query on graph g to obtain result set
PgqlResultSet resultSet = g.queryPgql("SELECT x MATCH (x) WHERE x.age > 24");
// Define a filter on the result set for the column "x"
VertexFilter resultSetVertexFilter = VertexFilter.fromPgqlResultSet(resultSet, "x");
// Create a subgraph of g containing the matched vertices in the resultSet and the edges that connect them if any.
PgxGraph newGraph = g.filter(resultSetVertexFilter);

You can create a subgraph from a result set edge filter, as shown in the following code:

• JShell
• Java

// Evaluates query on graph g to obtain result set
opg4j> var resultSet = g.queryPgql("SELECT e FROM MATCH ()-[e]->() WHERE e.cost < 100")
// Define a filter on the result set for the column "e"
opg4j> var resultSetEdgeFilter = EdgeFilter.fromPgqlResultSet(resultSet, "e")
// Create a subgraph of g containing the matched edges in the resultSet and their corresponding source and destination vertices.
opg4j> var newGraph = g.filter(resultSetEdgeFilter)

// Evaluates query on graph g to obtain result set
PgqlResultSet resultSet = g.queryPgql("SELECT e FROM MATCH ()-[e]->() WHERE e.cost < 100");
// Define a filter on the result set for the column "e"
EdgeFilter resultSetEdgeFilter = EdgeFilter.fromPgqlResultSet(resultSet, "e");
// Create a subgraph of g containing the matched edges in the resultSet and their corresponding source and destination vertices.
PgxGraph newGraph = g.filter(resultSetEdgeFilter);