Subselects in FROM clause, per ISO syntax: FROM (SELECT ...) [AS] alias.

(Don't forget that an alias is required.)  Views reimplemented as expanding
to subselect-in-FROM.  Grouping, aggregates, DISTINCT in views actually
work now (he says optimistically).  No UNION support in subselects/views
yet, but I have some ideas about that.  Rule-related permissions checking
moved out of rewriter and into executor.
INITDB REQUIRED!

3 files changed, 109 insertions, 100 deletions

diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 841806810e4..f072c719759 100644
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.103 2000/09/12 21:06:47 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.104 2000/09/29 18:21:26 tgl Exp $
  *
  * NOTES
  *	  The PerformAddAttribute() code, like most of the relation
@@ -1135,7 +1135,7 @@ AlterTableAddConstraint(char *relationName,
 					else
 						name="<unnamed>";
 
-					constlist=lcons(constr, NIL);
+					constlist = makeList1(constr);
 
 					rel = heap_openr(relationName, AccessExclusiveLock);
 
@@ -1158,10 +1158,11 @@ AlterTableAddConstraint(char *relationName,
 					makeRangeTable(pstate, NULL);
 					rte = addRangeTableEntry(pstate, relationName, NULL,
 											 false, true);
-					addRTEtoJoinTree(pstate, rte);
+					addRTEtoJoinList(pstate, rte);
 
 					/* Convert the A_EXPR in raw_expr into an EXPR */
-					expr = transformExpr(pstate, constr->raw_expr, EXPR_COLUMN_FIRST);
+					expr = transformExpr(pstate, constr->raw_expr,
+										 EXPR_COLUMN_FIRST);
 
 					/*
 					 * Make sure it yields a boolean result.
@@ -1185,14 +1186,14 @@ AlterTableAddConstraint(char *relationName,
 					/* And fix the opids */
 					fix_opids(expr);
 
-					qual = lcons(expr, NIL);
+					qual = makeList1(expr);
 
 					rte = makeNode(RangeTblEntry);
 					rte->relname = relationName;
 					rte->relid = RelationGetRelid(rel);
 					rte->eref = makeNode(Attr);
 					rte->eref->relname = relationName;
-					rtlist = lcons(rte, NIL);
+					rtlist = makeList1(rte);
 
 					/* 
 					 * Scan through the rows now, making the necessary things
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 2b3d8b85726..25b7517e1ec 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -5,7 +5,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.58 2000/09/12 21:06:47 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.59 2000/09/29 18:21:26 tgl Exp $
  *
  */
 
@@ -176,6 +176,12 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 		case T_IndexScan:
 			pname = "Index Scan";
 			break;
+		case T_TidScan:
+			pname = "Tid Scan";
+			break;
+		case T_SubqueryScan:
+			pname = "Subquery Scan";
+			break;
 		case T_Material:
 			pname = "Materialize";
 			break;
@@ -194,9 +200,6 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 		case T_Hash:
 			pname = "Hash";
 			break;
-		case T_TidScan:
-			pname = "Tid Scan";
-			break;
 		default:
 			pname = "???";
 			break;
@@ -225,37 +228,27 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 		case T_TidScan:
 			if (((Scan *) plan)->scanrelid > 0)
 			{
-				RangeTblEntry *rte = nth(((Scan *) plan)->scanrelid - 1, es->rtable);
+				RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
+											  es->rtable);
+
+				/* Assume it's on a real relation */
+				Assert(rte->relname);
 
 				appendStringInfo(str, " on %s",
 								 stringStringInfo(rte->relname));
-				if (rte->alias != NULL)
-				{
-					if ((strcmp(rte->alias->relname, rte->relname) != 0)
-						|| (length(rte->alias->attrs) > 0))
-					{
-						appendStringInfo(str, " %s",
-									stringStringInfo(rte->alias->relname));
-
-						if (length(rte->alias->attrs) > 0)
-						{
-							List	   *c;
-							int			firstEntry = true;
-
-							appendStringInfo(str, " (");
-							foreach(c, rte->alias->attrs)
-							{
-								if (!firstEntry)
-								{
-									appendStringInfo(str, ", ");
-									firstEntry = false;
-								}
-								appendStringInfo(str, "%s", strVal(lfirst(c)));
-							}
-							appendStringInfo(str, ")");
-						}
-					}
-				}
+				if (strcmp(rte->eref->relname, rte->relname) != 0)
+					appendStringInfo(str, " %s",
+									 stringStringInfo(rte->eref->relname));
+			}
+			break;
+		case T_SubqueryScan:
+			if (((Scan *) plan)->scanrelid > 0)
+			{
+				RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
+											  es->rtable);
+
+				appendStringInfo(str, " %s",
+								 stringStringInfo(rte->eref->relname));
 			}
 			break;
 		default:
@@ -284,7 +277,8 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 			for (i = 0; i < indent; i++)
 				appendStringInfo(str, "  ");
 			appendStringInfo(str, "    ->  ");
-			explain_outNode(str, ((SubPlan *) lfirst(lst))->plan, indent + 2, es);
+			explain_outNode(str, ((SubPlan *) lfirst(lst))->plan,
+							indent + 4, es);
 		}
 		es->rtable = saved_rtable;
 	}
@@ -307,32 +301,12 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 		explain_outNode(str, innerPlan(plan), indent + 3, es);
 	}
 
-	/* subPlan-s */
-	if (plan->subPlan)
-	{
-		List	   *saved_rtable = es->rtable;
-		List	   *lst;
-
-		for (i = 0; i < indent; i++)
-			appendStringInfo(str, "  ");
-		appendStringInfo(str, "  SubPlan\n");
-		foreach(lst, plan->subPlan)
-		{
-			es->rtable = ((SubPlan *) lfirst(lst))->rtable;
-			for (i = 0; i < indent; i++)
-				appendStringInfo(str, "  ");
-			appendStringInfo(str, "    ->  ");
-			explain_outNode(str, ((SubPlan *) lfirst(lst))->plan, indent + 4, es);
-		}
-		es->rtable = saved_rtable;
-	}
-
-	if (nodeTag(plan) == T_Append)
+	if (IsA(plan, Append))
 	{
+		Append	   *appendplan = (Append *) plan;
 		List	   *saved_rtable = es->rtable;
-		List	   *lst;
 		int			whichplan = 0;
-		Append	   *appendplan = (Append *) plan;
+		List	   *lst;
 
 		foreach(lst, appendplan->appendplans)
 		{
@@ -351,14 +325,55 @@ explain_outNode(StringInfo str, Plan *plan, int indent, ExplainState *es)
 
 			for (i = 0; i < indent; i++)
 				appendStringInfo(str, "  ");
-			appendStringInfo(str, "    ->  ");
+			appendStringInfo(str, "  ->  ");
 
-			explain_outNode(str, subnode, indent + 4, es);
+			explain_outNode(str, subnode, indent + 3, es);
 
 			whichplan++;
 		}
 		es->rtable = saved_rtable;
 	}
+
+	if (IsA(plan, SubqueryScan))
+	{
+		SubqueryScan *subqueryscan = (SubqueryScan *) plan;
+		Plan	   *subnode = subqueryscan->subplan;
+		RangeTblEntry *rte = rt_fetch(subqueryscan->scan.scanrelid,
+									  es->rtable);
+		List	   *saved_rtable = es->rtable;
+
+		Assert(rte->subquery != NULL);
+		es->rtable = rte->subquery->rtable;
+
+		for (i = 0; i < indent; i++)
+			appendStringInfo(str, "  ");
+		appendStringInfo(str, "  ->  ");
+
+		explain_outNode(str, subnode, indent + 3, es);
+
+		es->rtable = saved_rtable;
+	}
+
+	/* subPlan-s */
+	if (plan->subPlan)
+	{
+		List	   *saved_rtable = es->rtable;
+		List	   *lst;
+
+		for (i = 0; i < indent; i++)
+			appendStringInfo(str, "  ");
+		appendStringInfo(str, "  SubPlan\n");
+		foreach(lst, plan->subPlan)
+		{
+			es->rtable = ((SubPlan *) lfirst(lst))->rtable;
+			for (i = 0; i < indent; i++)
+				appendStringInfo(str, "  ");
+			appendStringInfo(str, "    ->  ");
+			explain_outNode(str, ((SubPlan *) lfirst(lst))->plan,
+							indent + 4, es);
+		}
+		es->rtable = saved_rtable;
+	}
 }
 
 static char *
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c
index d1d63000999..1f245f11db2 100644
--- a/src/backend/commands/view.c
+++ b/src/backend/commands/view.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: view.c,v 1.48 2000/09/12 21:06:47 tgl Exp $
+ *	$Id: view.c,v 1.49 2000/09/29 18:21:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,70 +39,60 @@
 static void
 DefineVirtualRelation(char *relname, List *tlist)
 {
-	CreateStmt	createStmt;
+	CreateStmt *createStmt = makeNode(CreateStmt);
 	List	   *attrList,
 			   *t;
-	TargetEntry *entry;
-	Resdom	   *res;
-	char	   *resname;
-	char	   *restypename;
 
 	/*
-	 * create a list with one entry per attribute of this relation. Each
-	 * entry is a two element list. The first element is the name of the
-	 * attribute (a string) and the second the name of the type (NOTE: a
-	 * string, not a type id!).
+	 * create a list of ColumnDef nodes based on the names and types of
+	 * the (non-junk) targetlist items from the view's SELECT list.
 	 */
 	attrList = NIL;
-	if (tlist != NIL)
+	foreach(t, tlist)
 	{
-		foreach(t, tlist)
+		TargetEntry *entry = lfirst(t);
+		Resdom	   *res = entry->resdom;
+
+		if (! res->resjunk)
 		{
+			char	   *resname = res->resname;
+			char	   *restypename = typeidTypeName(res->restype);
 			ColumnDef  *def = makeNode(ColumnDef);
-			TypeName   *typename;
-
-			/*
-			 * find the names of the attribute & its type
-			 */
-			entry = lfirst(t);
-			res = entry->resdom;
-			resname = res->resname;
-			restypename = typeidTypeName(res->restype);
+			TypeName   *typename = makeNode(TypeName);
 
-			typename = makeNode(TypeName);
+			def->colname = pstrdup(resname);
 
 			typename->name = pstrdup(restypename);
 			typename->typmod = res->restypmod;
-
-			def->colname = pstrdup(resname);
-
 			def->typename = typename;
 
 			def->is_not_null = false;
+			def->is_sequence = false;
 			def->raw_default = NULL;
 			def->cooked_default = NULL;
+			def->constraints = NIL;
 
 			attrList = lappend(attrList, def);
 		}
 	}
-	else
+
+	if (attrList == NIL)
 		elog(ERROR, "attempted to define virtual relation with no attrs");
 
 	/*
-	 * now create the parametesr for keys/inheritance etc. All of them are
+	 * now create the parameters for keys/inheritance etc. All of them are
 	 * nil...
 	 */
-	createStmt.relname = relname;
-	createStmt.istemp = false;
-	createStmt.tableElts = attrList;
-/*	  createStmt.tableType = NULL;*/
-	createStmt.inhRelnames = NIL;
-	createStmt.constraints = NIL;
+	createStmt->relname = relname;
+	createStmt->istemp = false;
+	createStmt->tableElts = attrList;
+	createStmt->inhRelnames = NIL;
+	createStmt->constraints = NIL;
 
 	/*
 	 * finally create the relation...
 	 */
-	DefineRelation(&createStmt, RELKIND_VIEW);
+	DefineRelation(createStmt, RELKIND_VIEW);
 }
 
 /*------------------------------------------------------------------
@@ -149,13 +139,12 @@ FormViewRetrieveRule(char *viewName, Query *viewParse)
 
 	attr = makeNode(Attr);
 	attr->relname = pstrdup(viewName);
-/*	  attr->refname = pstrdup(viewName);*/
 	rule->rulename = pstrdup(rname);
 	rule->whereClause = NULL;
 	rule->event = CMD_SELECT;
 	rule->object = attr;
 	rule->instead = true;
-	rule->actions = lcons(viewParse, NIL);
+	rule->actions = makeList1(viewParse);
 
 	return rule;
 }
@@ -231,6 +220,10 @@ UpdateRangeTableOfViewParse(char *viewName, Query *viewParse)
 	rt_entry2 = addRangeTableEntry(NULL, viewName,
 								   makeAttr("*NEW*", NULL),
 								   false, false);
+	/* Must override addRangeTableEntry's default access-check flags */
+	rt_entry1->checkForRead = false;
+	rt_entry2->checkForRead = false;
+
 	new_rt = lcons(rt_entry1, lcons(rt_entry2, viewParse->rtable));
 
 	/*