Implement the FILTER clause for aggregate function calls.

This is SQL-standard with a few extensions, namely support for
subqueries and outer references in clause expressions.

catversion bump due to change in Aggref and WindowFunc.

David Fetter, reviewed by Dean Rasheed.

6 files changed, 20 insertions, 0 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index ad7378dd935..f524a7a9943 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -1137,6 +1137,7 @@ _copyAggref(const Aggref *from)
 	COPY_NODE_FIELD(args);
 	COPY_NODE_FIELD(aggorder);
 	COPY_NODE_FIELD(aggdistinct);
+	COPY_NODE_FIELD(aggfilter);
 	COPY_SCALAR_FIELD(aggstar);
 	COPY_SCALAR_FIELD(agglevelsup);
 	COPY_LOCATION_FIELD(location);
@@ -1157,6 +1158,7 @@ _copyWindowFunc(const WindowFunc *from)
 	COPY_SCALAR_FIELD(wincollid);
 	COPY_SCALAR_FIELD(inputcollid);
 	COPY_NODE_FIELD(args);
+	COPY_NODE_FIELD(aggfilter);
 	COPY_SCALAR_FIELD(winref);
 	COPY_SCALAR_FIELD(winstar);
 	COPY_SCALAR_FIELD(winagg);
@@ -2152,6 +2154,7 @@ _copyFuncCall(const FuncCall *from)
 	COPY_NODE_FIELD(funcname);
 	COPY_NODE_FIELD(args);
 	COPY_NODE_FIELD(agg_order);
+	COPY_NODE_FIELD(agg_filter);
 	COPY_SCALAR_FIELD(agg_star);
 	COPY_SCALAR_FIELD(agg_distinct);
 	COPY_SCALAR_FIELD(func_variadic);
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index e0d4bca809b..904cf374d81 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -196,6 +196,7 @@ _equalAggref(const Aggref *a, const Aggref *b)
 	COMPARE_NODE_FIELD(args);
 	COMPARE_NODE_FIELD(aggorder);
 	COMPARE_NODE_FIELD(aggdistinct);
+	COMPARE_NODE_FIELD(aggfilter);
 	COMPARE_SCALAR_FIELD(aggstar);
 	COMPARE_SCALAR_FIELD(agglevelsup);
 	COMPARE_LOCATION_FIELD(location);
@@ -211,6 +212,7 @@ _equalWindowFunc(const WindowFunc *a, const WindowFunc *b)
 	COMPARE_SCALAR_FIELD(wincollid);
 	COMPARE_SCALAR_FIELD(inputcollid);
 	COMPARE_NODE_FIELD(args);
+	COMPARE_NODE_FIELD(aggfilter);
 	COMPARE_SCALAR_FIELD(winref);
 	COMPARE_SCALAR_FIELD(winstar);
 	COMPARE_SCALAR_FIELD(winagg);
@@ -1993,6 +1995,7 @@ _equalFuncCall(const FuncCall *a, const FuncCall *b)
 	COMPARE_NODE_FIELD(funcname);
 	COMPARE_NODE_FIELD(args);
 	COMPARE_NODE_FIELD(agg_order);
+	COMPARE_NODE_FIELD(agg_filter);
 	COMPARE_SCALAR_FIELD(agg_star);
 	COMPARE_SCALAR_FIELD(agg_distinct);
 	COMPARE_SCALAR_FIELD(func_variadic);
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index 245aef226a5..0f8a282ec81 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -526,6 +526,7 @@ makeFuncCall(List *name, List *args, int location)
 	n->args = args;
 	n->location = location;
 	n->agg_order = NIL;
+	n->agg_filter = NULL;
 	n->agg_star = FALSE;
 	n->agg_distinct = FALSE;
 	n->func_variadic = FALSE;
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index 42d6621a822..310400eedab 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -1570,6 +1570,8 @@ expression_tree_walker(Node *node,
 				if (expression_tree_walker((Node *) expr->aggdistinct,
 										   walker, context))
 					return true;
+				if (walker((Node *) expr->aggfilter, context))
+					return true;
 			}
 			break;
 		case T_WindowFunc:
@@ -1580,6 +1582,8 @@ expression_tree_walker(Node *node,
 				if (expression_tree_walker((Node *) expr->args,
 										   walker, context))
 					return true;
+				if (walker((Node *) expr->aggfilter, context))
+					return true;
 			}
 			break;
 		case T_ArrayRef:
@@ -2079,6 +2083,7 @@ expression_tree_mutator(Node *node,
 				MUTATE(newnode->args, aggref->args, List *);
 				MUTATE(newnode->aggorder, aggref->aggorder, List *);
 				MUTATE(newnode->aggdistinct, aggref->aggdistinct, List *);
+				MUTATE(newnode->aggfilter, aggref->aggfilter, Expr *);
 				return (Node *) newnode;
 			}
 			break;
@@ -2089,6 +2094,7 @@ expression_tree_mutator(Node *node,
 
 				FLATCOPY(newnode, wfunc, WindowFunc);
 				MUTATE(newnode->args, wfunc->args, List *);
+				MUTATE(newnode->aggfilter, wfunc->aggfilter, Expr *);
 				return (Node *) newnode;
 			}
 			break;
@@ -2951,6 +2957,8 @@ raw_expression_tree_walker(Node *node,
 					return true;
 				if (walker(fcall->agg_order, context))
 					return true;
+				if (walker(fcall->agg_filter, context))
+					return true;
 				if (walker(fcall->over, context))
 					return true;
 				/* function name is deemed uninteresting */
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index b2183f42137..2475f8d520e 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -958,6 +958,7 @@ _outAggref(StringInfo str, const Aggref *node)
 	WRITE_NODE_FIELD(args);
 	WRITE_NODE_FIELD(aggorder);
 	WRITE_NODE_FIELD(aggdistinct);
+	WRITE_NODE_FIELD(aggfilter);
 	WRITE_BOOL_FIELD(aggstar);
 	WRITE_UINT_FIELD(agglevelsup);
 	WRITE_LOCATION_FIELD(location);
@@ -973,6 +974,7 @@ _outWindowFunc(StringInfo str, const WindowFunc *node)
 	WRITE_OID_FIELD(wincollid);
 	WRITE_OID_FIELD(inputcollid);
 	WRITE_NODE_FIELD(args);
+	WRITE_NODE_FIELD(aggfilter);
 	WRITE_UINT_FIELD(winref);
 	WRITE_BOOL_FIELD(winstar);
 	WRITE_BOOL_FIELD(winagg);
@@ -2080,6 +2082,7 @@ _outFuncCall(StringInfo str, const FuncCall *node)
 	WRITE_NODE_FIELD(funcname);
 	WRITE_NODE_FIELD(args);
 	WRITE_NODE_FIELD(agg_order);
+	WRITE_NODE_FIELD(agg_filter);
 	WRITE_BOOL_FIELD(agg_star);
 	WRITE_BOOL_FIELD(agg_distinct);
 	WRITE_BOOL_FIELD(func_variadic);
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 3a16e9db524..30c51504c3f 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -479,6 +479,7 @@ _readAggref(void)
 	READ_NODE_FIELD(args);
 	READ_NODE_FIELD(aggorder);
 	READ_NODE_FIELD(aggdistinct);
+	READ_NODE_FIELD(aggfilter);
 	READ_BOOL_FIELD(aggstar);
 	READ_UINT_FIELD(agglevelsup);
 	READ_LOCATION_FIELD(location);
@@ -499,6 +500,7 @@ _readWindowFunc(void)
 	READ_OID_FIELD(wincollid);
 	READ_OID_FIELD(inputcollid);
 	READ_NODE_FIELD(args);
+	READ_NODE_FIELD(aggfilter);
 	READ_UINT_FIELD(winref);
 	READ_BOOL_FIELD(winstar);
 	READ_BOOL_FIELD(winagg);