Add support for chained expressions in CASE (#1431)

Adds logic that implements CASE in chained expressions. Adds regression tests for CASE chained expression logic.
apache · Dec 1, 2023 · c159584 · c159584
1 parent b2d616d
commit c159584
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diff --git a/regress/expected/expr.out b/regress/expected/expr.out
@@ -6635,6 +6635,191 @@ $$ ) AS (case_statement agtype);
  {"id": 844424930131970, "label": "connected_to", "end_id": 281474976710660, "start_id": 281474976710659, "properties": {"k": 1, "id": 2}}::edge
 (2 rows)
 
+--CASE chained expressions
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+                                case_statement                                 
+-------------------------------------------------------------------------------
+ {"id": 281474976710657, "label": "", "properties": {"i": 1, "id": 1}}::vertex
+ "none"
+ "none"
+ "none"
+ "none"
+ "none"
+(6 rows)
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE
+    WHEN null THEN 'should not return me'
+    WHEN n.i = (1 = 1) THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+                                        case_statement                                        
+----------------------------------------------------------------------------------------------
+ "none"
+ "none"
+ "none"
+ {"id": 281474976710660, "label": "", "properties": {"i": true, "j": false, "id": 4}}::vertex
+ "none"
+ "none"
+(6 rows)
+
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+ case_statement 
+----------------
+ "none"
+ "none"
+ "none"
+ "none"
+ "none"
+ "none"
+(6 rows)
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+                                         case_statement                                         
+------------------------------------------------------------------------------------------------
+ "none"
+ {"id": 281474976710658, "label": "", "properties": {"i": "a", "j": "b", "id": 2}}::vertex
+ {"id": 281474976710659, "label": "", "properties": {"i": 0, "j": 1, "id": 3}}::vertex
+ {"id": 281474976710660, "label": "", "properties": {"i": true, "j": false, "id": 4}}::vertex
+ {"id": 281474976710661, "label": "", "properties": {"i": [], "j": [0, 1, 2], "id": 5}}::vertex
+ {"id": 281474976710662, "label": "", "properties": {"i": {}, "j": {"i": 1}, "id": 6}}::vertex
+(6 rows)
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n.i = (1 = 1) THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+                                         case_statement                                         
+------------------------------------------------------------------------------------------------
+ {"id": 281474976710657, "label": "", "properties": {"i": 1, "id": 1}}::vertex
+ {"id": 281474976710658, "label": "", "properties": {"i": "a", "j": "b", "id": 2}}::vertex
+ {"id": 281474976710659, "label": "", "properties": {"i": 0, "j": 1, "id": 3}}::vertex
+ "none"
+ {"id": 281474976710661, "label": "", "properties": {"i": [], "j": [0, 1, 2], "id": 5}}::vertex
+ {"id": 281474976710662, "label": "", "properties": {"i": {}, "j": {"i": 1}, "id": 6}}::vertex
+(6 rows)
+
+--should return n
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+                                         case_statement                                         
+------------------------------------------------------------------------------------------------
+ {"id": 281474976710657, "label": "", "properties": {"i": 1, "id": 1}}::vertex
+ {"id": 281474976710658, "label": "", "properties": {"i": "a", "j": "b", "id": 2}}::vertex
+ {"id": 281474976710659, "label": "", "properties": {"i": 0, "j": 1, "id": 3}}::vertex
+ {"id": 281474976710660, "label": "", "properties": {"i": true, "j": false, "id": 4}}::vertex
+ {"id": 281474976710661, "label": "", "properties": {"i": [], "j": [0, 1, 2], "id": 5}}::vertex
+ {"id": 281474976710662, "label": "", "properties": {"i": {}, "j": {"i": 1}, "id": 6}}::vertex
+(6 rows)
+
+--chained expression in THEN
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE 
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 THEN n.i = 1 = 1
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+ case_statement 
+----------------
+ true
+ "none"
+ "none"
+ "none"
+ "none"
+ "none"
+(6 rows)
+
+--order of operations in then
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN (n.i = 1) = 1
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+ case_statement 
+----------------
+ false
+ false
+ false
+ false
+ false
+ false
+(6 rows)
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN n.i = (1 = 1)
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+ case_statement 
+----------------
+ false
+ false
+ false
+ true
+ false
+ false
+(6 rows)
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN n.i = (1 = 0)
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+ case_statement 
+----------------
+ false
+ false
+ false
+ false
+ false
+ false
+(6 rows)
+
 --CASE with count()
 --count(*)
 SELECT * FROM cypher('case_statement', $$

diff --git a/regress/sql/expr.sql b/regress/sql/expr.sql
@@ -2742,6 +2742,101 @@ SELECT * FROM cypher('case_statement', $$
   END
 $$ ) AS (case_statement agtype);
 
+--CASE chained expressions
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE
+    WHEN null THEN 'should not return me'
+    WHEN n.i = (1 = 1) THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n.i = (1 = 1) THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+--should return n
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n = 1
+    WHEN null THEN 'should not return me'
+    WHEN n = 1 = 1 THEN n
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+--chained expression in THEN
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE 
+    WHEN null THEN 'should not return me'
+    WHEN n.i = 1 THEN n.i = 1 = 1
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+--order of operations in then
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN (n.i = 1) = 1
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN n.i = (1 = 1)
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
+SELECT * FROM cypher('case_statement', $$
+  MATCH (n)
+  RETURN CASE n
+    WHEN null THEN 'should not return me'
+    WHEN n THEN n.i = (1 = 0)
+    ELSE 'none'
+  END
+$$ ) AS (case_statement agtype);
+
 --CASE with count()
 
 --count(*)

diff --git a/src/backend/parser/cypher_expr.c b/src/backend/parser/cypher_expr.c
@@ -1493,6 +1493,17 @@ static Node *transform_CaseExpr(cypher_parsestate *cpstate, CaseExpr
         warg = (Node *) w->expr;
         if (placeholder)
         {
+            if(is_ag_node(warg, cypher_comparison_aexpr) ||
+               is_ag_node(warg, cypher_comparison_boolexpr) )
+            {
+                List *funcname = list_make1(makeString("ag_catalog"));
+                funcname = lappend(funcname, makeString("bool_to_agtype"));
+
+                warg = (Node *) makeFuncCall(funcname, list_make1(warg),
+                                             COERCE_EXPLICIT_CAST,
+                                             cexpr->location);
+            }
+
             /* shorthand form was specified, so expand... */
             warg = (Node *) makeSimpleA_Expr(AEXPR_OP, "=",
                                              (Node *) placeholder,
@@ -1506,6 +1517,18 @@ static Node *transform_CaseExpr(cypher_parsestate *cpstate, CaseExpr
                                                 "CASE/WHEN");
 
         warg = (Node *) w->result;
+
+        if(is_ag_node(warg, cypher_comparison_aexpr) ||
+           is_ag_node(warg, cypher_comparison_boolexpr) )
+        {
+            List *funcname = list_make1(makeString("ag_catalog"));
+            funcname = lappend(funcname, makeString("bool_to_agtype"));
+
+            warg = (Node *) makeFuncCall(funcname, list_make1(warg),
+                                         COERCE_EXPLICIT_CAST,
+                                         cexpr->location);
+        }
+
         neww->result = (Expr *) transform_cypher_expr_recurse(cpstate, warg);
         neww->location = w->location;