feat: Implement OPTIONAL MATCH (apache#175)

* feat: Implement `OPTIONAL MATCH` * Reflect review. * Reflect review * Reflect review * Reflect review * Reflect review * Reflect Review * Reflect review * Reflect review * Fix broken
muhammadshoaib · Feb 18, 2022 · bbdd52f · bbdd52f
1 parent 2b35db8
commit bbdd52f
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Showing 9 changed files with 359 additions and 50 deletions.
diff --git a/regress/expected/cypher_match.out b/regress/expected/cypher_match.out
@@ -889,6 +889,68 @@ $$) AS (i agtype);
  {"id": 1688849860263938, "label": "v2", "properties": {"id": "middle"}}::vertex
 (3 rows)
 
+--
+-- Optional Match
+--
+SELECT * FROM cypher('cypher_match', $$
+    CREATE (:opt_match_v {name: 'someone'})-[:opt_match_e]->(:opt_match_v {name: 'somebody'}),
+           (:opt_match_v {name: 'anybody'})-[:opt_match_e]->(:opt_match_v {name: 'nobody'})
+$$) AS (u agtype);
+ u 
+---
+(0 rows)
+
+SELECT * FROM cypher('cypher_match', $$
+    MATCH (u:opt_match_v)
+    OPTIONAL MATCH (u)-[m]-(l)
+    RETURN u.name as u, type(m), l.name as l
+    ORDER BY u, m, l
+$$) AS (u agtype, m agtype, l agtype);
+     u      |       m       |     l      
+------------+---------------+------------
+ "someone"  | "opt_match_e" | "somebody"
+ "somebody" | "opt_match_e" | "someone"
+ "anybody"  | "opt_match_e" | "nobody"
+ "nobody"   | "opt_match_e" | "anybody"
+(4 rows)
+
+SELECT * FROM cypher('cypher_match', $$
+    OPTIONAL MATCH (n:opt_match_v)-[r]->(p), (m:opt_match_v)-[s]->(q)
+    WHERE id(n) <> id(m)
+    RETURN n.name as n, type(r) AS r, p.name as p,
+           m.name AS m, type(s) AS s, q.name AS q
+    ORDER BY n, p, m, q
+$$) AS (n agtype, r agtype, p agtype, m agtype, s agtype, q agtype);
+     n     |       r       |     p      |     m     |       s       |     q      
+-----------+---------------+------------+-----------+---------------+------------
+ "someone" | "opt_match_e" | "somebody" | "anybody" | "opt_match_e" | "nobody"
+ "anybody" | "opt_match_e" | "nobody"   | "someone" | "opt_match_e" | "somebody"
+(2 rows)
+
+SELECT * FROM cypher('cypher_match', $$
+    MATCH (n:opt_match_v), (m:opt_match_v)
+    WHERE id(n) <> id(m)
+    OPTIONAL MATCH (n)-[r]->(p), (m)-[s]->(q)
+    RETURN n.name AS n, type(r) AS r, p.name AS p,
+           m.name AS m, type(s) AS s, q.name AS q
+    ORDER BY n, p, m, q
+ $$) AS (n agtype, r agtype, p agtype, m agtype, s agtype, q agtype);
+     n      |       r       |     p      |     m      |       s       |     q      
+------------+---------------+------------+------------+---------------+------------
+ "someone"  | "opt_match_e" | "somebody" | "anybody"  | "opt_match_e" | "nobody"
+ "someone"  |               |            | "somebody" |               | 
+ "someone"  |               |            | "nobody"   |               | 
+ "somebody" |               |            | "someone"  |               | 
+ "somebody" |               |            | "anybody"  |               | 
+ "somebody" |               |            | "nobody"   |               | 
+ "anybody"  | "opt_match_e" | "nobody"   | "someone"  | "opt_match_e" | "somebody"
+ "anybody"  |               |            | "somebody" |               | 
+ "anybody"  |               |            | "nobody"   |               | 
+ "nobody"   |               |            | "someone"  |               | 
+ "nobody"   |               |            | "somebody" |               | 
+ "nobody"   |               |            | "anybody"  |               | 
+(12 rows)
+
 --
 -- JIRA: AGE2-544
 --
@@ -981,7 +1043,7 @@ $$) as (f agtype, t agtype);
 -- Clean up
 --
 SELECT drop_graph('cypher_match', true);
-NOTICE:  drop cascades to 14 other objects
+NOTICE:  drop cascades to 16 other objects
 DETAIL:  drop cascades to table cypher_match._ag_label_vertex
 drop cascades to table cypher_match._ag_label_edge
 drop cascades to table cypher_match.v
@@ -996,6 +1058,8 @@ drop cascades to table cypher_match.self
 drop cascades to table cypher_match.duplicate
 drop cascades to table cypher_match.dup_edge
 drop cascades to table cypher_match.other_v
+drop cascades to table cypher_match.opt_match_v
+drop cascades to table cypher_match.opt_match_e
 NOTICE:  graph "cypher_match" has been dropped
  drop_graph 
 ------------

diff --git a/regress/sql/cypher_match.sql b/regress/sql/cypher_match.sql
@@ -456,6 +456,39 @@ SELECT * FROM cypher('cypher_match', $$
 	RETURN u SKIP 7 LIMIT 3
 $$) AS (i agtype);
 
+
+--
+-- Optional Match
+--
+SELECT * FROM cypher('cypher_match', $$
+    CREATE (:opt_match_v {name: 'someone'})-[:opt_match_e]->(:opt_match_v {name: 'somebody'}),
+           (:opt_match_v {name: 'anybody'})-[:opt_match_e]->(:opt_match_v {name: 'nobody'})
+$$) AS (u agtype);
+
+SELECT * FROM cypher('cypher_match', $$
+    MATCH (u:opt_match_v)
+    OPTIONAL MATCH (u)-[m]-(l)
+    RETURN u.name as u, type(m), l.name as l
+    ORDER BY u, m, l
+$$) AS (u agtype, m agtype, l agtype);
+
+SELECT * FROM cypher('cypher_match', $$
+    OPTIONAL MATCH (n:opt_match_v)-[r]->(p), (m:opt_match_v)-[s]->(q)
+    WHERE id(n) <> id(m)
+    RETURN n.name as n, type(r) AS r, p.name as p,
+           m.name AS m, type(s) AS s, q.name AS q
+    ORDER BY n, p, m, q
+$$) AS (n agtype, r agtype, p agtype, m agtype, s agtype, q agtype);
+
+SELECT * FROM cypher('cypher_match', $$
+    MATCH (n:opt_match_v), (m:opt_match_v)
+    WHERE id(n) <> id(m)
+    OPTIONAL MATCH (n)-[r]->(p), (m)-[s]->(q)
+    RETURN n.name AS n, type(r) AS r, p.name AS p,
+           m.name AS m, type(s) AS s, q.name AS q
+    ORDER BY n, p, m, q
+ $$) AS (n agtype, r agtype, p agtype, m agtype, s agtype, q agtype);
+
 --
 -- JIRA: AGE2-544
 --

diff --git a/src/backend/nodes/cypher_outfuncs.c b/src/backend/nodes/cypher_outfuncs.c
@@ -129,6 +129,7 @@ void out_cypher_match(StringInfo str, const ExtensibleNode *node)
 
     WRITE_NODE_FIELD(pattern);
     WRITE_NODE_FIELD(where);
+    WRITE_BOOL_FIELD(optional);
 }
 
 // serialization function for the cypher_create ExtensibleNode.

diff --git a/src/backend/parser/cypher_analyze.c b/src/backend/parser/cypher_analyze.c
@@ -578,6 +578,8 @@ static Query *analyze_cypher_and_coerce(List *stmt, RangeTblFunction *rtfunc,
     ListCell *lc2;
     ListCell *lc3;
 
+    int attr_count = 0;
+
     pstate = make_parsestate(parent_pstate);
 
     query = makeNode(Query);
@@ -597,8 +599,18 @@ static Query *analyze_cypher_and_coerce(List *stmt, RangeTblFunction *rtfunc,
     pstate->p_lateral_active = false;
     pstate->p_expr_kind = EXPR_KIND_NONE;
 
+    // ALIAS Syntax makes `RESJUNK`. So, It must be skipping.
+    foreach(lt, subquery->targetList)
+    {
+        TargetEntry *te = lfirst(lt);
+        if (!te->resjunk)
+        {
+            attr_count++;
+        }
+    }
+
     // check the number of attributes first
-    if (list_length(subquery->targetList) != rtfunc->funccolcount)
+    if (attr_count != rtfunc->funccolcount)
     {
         ereport(ERROR,
                 (errcode(ERRCODE_DATATYPE_MISMATCH),