Implementation of UNIONs.

Author: bmomjian

src/backend/nodes/copyfuncs.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.25 1997/12/23 21:49:03 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.26 1997/12/24 06:05:52 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1566,7 +1566,18 @@ _copyQuery(Query *from)
 	}
 	else
 		newnode->qry_aggs = NULL;
-		
+
+	if (from->unionClause)
+	{
+		List *ulist, *temp_list = NIL;
+
+		foreach(ulist, from->unionClause)
+			temp_list = lappend(temp_list,copyObject(lfirst(ulist)));
+		newnode->unionClause = temp_list;
+	}
+	else
+		newnode->unionClause = NULL;
+ 				
 	return newnode;
 }
 

src/backend/optimizer/plan/planner.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.15 1997/12/22 05:42:08 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.16 1997/12/24 06:06:01 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -81,11 +81,19 @@ planner(Query *parse)
 	int			rt_index;
 
 
-	/*
-	 * plan inheritance
-	 */
-	rt_index = first_matching_rt_entry(rangetable, INHERITS_FLAG);
-	if (rt_index != -1)
+	if (parse->unionClause)
+	{
+		result_plan = (Plan *) plan_union_queries(0, /* none */
+													parse,
+													UNION_FLAG);
+		/* XXX do we need to do this? bjm 12/19/97 */
+		tlist = preprocess_targetlist(tlist,
+									  parse->commandType,
+									  parse->resultRelation,
+									  parse->rtable);
+	}
+	else if ((rt_index =
+				first_matching_rt_entry(rangetable, INHERITS_FLAG)) != -1)
 	{
 		result_plan = (Plan *) plan_union_queries((Index) rt_index,
 													parse,

src/backend/optimizer/prep/prepunion.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.12 1997/12/21 05:18:28 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.13 1997/12/24 06:06:07 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -149,20 +149,51 @@ plan_union_queries(Index rt_index,
 				find_all_inheritors(lconsi(rt_entry->relid,
 										   NIL),
 									NIL);
+			/*
+			 * Remove the flag for this relation, since we're about to handle it
+			 * (do it before recursing!). XXX destructive parse tree change
+			 */
+			switch (flag)
+			{
+				case INHERITS_FLAG:
+					rt_fetch(rt_index, rangetable)->inh = false;
+					break;
+				default:
+					break;
+			}
+		
+			/*
+			 * XXX - can't find any reason to sort union-relids as paul did, so
+			 * we're leaving it out for now (maybe forever) - jeff & lp
+			 *
+			 * [maybe so. btw, jeff & lp did the lisp conversion, according to Paul.
+			 * -- ay 10/94.]
+			 */
+			union_plans = plan_union_query(union_relids, rt_index, rt_entry,
+										   parse, flag, &union_rt_entries);
+		
+			return (make_append(union_plans,
+								rt_index,
+								union_rt_entries,
+								((Plan *) lfirst(union_plans))->targetlist));
 			break;
-
-#if 0
+			
 		case UNION_FLAG:
 			{
-				Index		rt_index = 0;
+				List *ulist, *hold_union, *union_plans;
 
-				union_plans = handleunion(root, rangetable, tlist, qual);
+				hold_union = parse->unionClause;
+				parse->unionClause = NULL; /* prevent looping */
+
+				union_plans = lcons(planner(parse), NIL);
+				
+				foreach(ulist, hold_union)
+					union_plans = lappend(union_plans, planner(lfirst(ulist)));
 				return (make_append(union_plans,
 									rt_index, rangetable,
 							((Plan *) lfirst(union_plans))->targetlist));
 			}
 			break;
-#endif
 
 		case VERSION_FLAG:
 			union_relids = VersionGetParents(rt_entry->relid);
@@ -172,34 +203,6 @@ plan_union_queries(Index rt_index,
 			/* do nothing */
 			break;
 	}
-
-	/*
-	 * Remove the flag for this relation, since we're about to handle it
-	 * (do it before recursing!). XXX destructive parse tree change
-	 */
-	switch (flag)
-	{
-		case INHERITS_FLAG:
-			rt_fetch(rt_index, rangetable)->inh = false;
-			break;
-		default:
-			break;
-	}
-
-	/*
-	 * XXX - can't find any reason to sort union-relids as paul did, so
-	 * we're leaving it out for now (maybe forever) - jeff & lp
-	 *
-	 * [maybe so. btw, jeff & lp did the lisp conversion, according to Paul.
-	 * -- ay 10/94.]
-	 */
-	union_plans = plan_union_query(union_relids, rt_index, rt_entry,
-								   parse, flag, &union_rt_entries);
-
-	return (make_append(union_plans,
-						rt_index,
-						union_rt_entries,
-						((Plan *) lfirst(union_plans))->targetlist));
 }
 
 

src/backend/parser/analyze.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.55 1997/12/23 19:39:42 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.56 1997/12/24 06:06:18 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -821,18 +821,7 @@ transformSelectStmt(ParseState *pstate, RetrieveStmt *stmt)
 	/* fix where clause */
 	qry->qual = transformWhereClause(pstate, stmt->whereClause);
 
-	/* check subselect clause */
-	if (stmt->unionClause)
-	{
-		elog(NOTICE, "UNION not yet supported; using first SELECT only", NULL);
-
-		/* XXX HACK just playing with union clause - thomas 1997-12-19 */
-		if ((qry->uniqueFlag == NULL)
-		 && (! ((SubSelect *)lfirst(stmt->unionClause))->unionall))
-			qry->uniqueFlag = "*";
-	}
-
-	/* check subselect clause */
+	/* check having clause */
 	if (stmt->havingClause)
 		elog(NOTICE, "HAVING not yet supported; ignore clause", NULL);
 
@@ -842,7 +831,6 @@ transformSelectStmt(ParseState *pstate, RetrieveStmt *stmt)
 										  qry->targetList,
 										  qry->uniqueFlag);
 
-	/* fix group by clause */
 	qry->groupClause = transformGroupClause(pstate,
 											stmt->groupClause,
 											qry->targetList);
@@ -851,6 +839,20 @@ transformSelectStmt(ParseState *pstate, RetrieveStmt *stmt)
 	if (pstate->p_numAgg > 0)
 		finalizeAggregates(pstate, qry);
 
+	if (stmt->unionClause)
+	{
+		List *ulist = NIL;
+		QueryTreeList *qlist;
+		int i;
+		
+		qlist = parse_analyze(stmt->unionClause);
+		for (i=0; i < qlist->len; i++)
+			ulist = lappend(ulist, qlist->qtrees[i]);
+		qry->unionClause = ulist;
+	}
+	else
+	    qry->unionClause = NULL;
+
 	return (Query *) qry;
 }
 

src/backend/parser/gram.y

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.80 1997/12/23 19:47:32 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.81 1997/12/24 06:06:26 momjian Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -120,19 +120,20 @@ Oid	param_type(int t); /* used in parse_expr.c */
 		ProcedureStmt, 	RecipeStmt, RemoveAggrStmt, RemoveOperStmt,
 		RemoveFuncStmt, RemoveStmt,
 		RenameStmt, RevokeStmt, RuleStmt, TransactionStmt, ViewStmt, LoadStmt,
-		CreatedbStmt, DestroydbStmt, VacuumStmt, RetrieveStmt, CursorStmt,
-		ReplaceStmt, AppendStmt, NotifyStmt, DeleteStmt, ClusterStmt,
+		CreatedbStmt, DestroydbStmt, VacuumStmt, CursorStmt, SubSelect,
+		ReplaceStmt, AppendStmt, RetrieveStmt, NotifyStmt, DeleteStmt, ClusterStmt,
 		ExplainStmt, VariableSetStmt, VariableShowStmt, VariableResetStmt,
 		CreateUserStmt, AlterUserStmt, DropUserStmt
 
+%type <rtstmt> 
+
 %type <str>		opt_database, location
 
 %type <pboolean> user_createdb_clause, user_createuser_clause
 %type <str>   user_passwd_clause
 %type <str>   user_valid_clause
 %type <list>  user_group_list, user_group_clause
 
-%type <node>	SubSelect
 %type <str>		join_expr, join_outer, join_spec
 %type <boolean> TriggerActionTime, TriggerForSpec, PLangTrusted
 
@@ -1049,19 +1050,10 @@ OptArchiveType:  ARCHIVE '=' NONE						{ }
 
 CreateAsStmt:  CREATE TABLE relation_name OptCreateAs AS SubSelect
 				{
-					RetrieveStmt *n = makeNode(RetrieveStmt);
-					SubSelect *s = (SubSelect *)$6;
-					n->unique = s->unique;
-					n->targetList = s->targetList;
+					RetrieveStmt *n = (RetrieveStmt *)$6;
 					if ($4 != NIL)
 						mapTargetColumns($4, n->targetList);
 					n->into = $3;
-					n->fromClause = s->fromClause;
-					n->whereClause = s->whereClause;
-					n->groupClause = s->groupClause;
-					n->havingClause = s->havingClause;
-					n->unionClause = NULL;
-					n->sortClause = NULL;
 					$$ = (Node *)n;
 				}
 		;
@@ -2291,7 +2283,7 @@ RetrieveStmt:  SELECT opt_unique res_target_list2
 
 union_clause:  UNION opt_union select_list
 				{
-					SubSelect *n = lfirst($3);
+					RetrieveStmt *n = (RetrieveStmt *)lfirst($3);
 					n->unionall = $2;
 					$$ = $3;
 				}
@@ -2301,7 +2293,7 @@ union_clause:  UNION opt_union select_list
 
 select_list:  select_list UNION opt_union SubSelect
 				{
-					SubSelect *n = (SubSelect *)$4;
+					RetrieveStmt *n = (RetrieveStmt *)$4;
 					n->unionall = $3;
 					$$ = lappend($1, $4);
 				}
@@ -2313,7 +2305,7 @@ SubSelect:	SELECT opt_unique res_target_list2
 			 from_clause where_clause
 			 group_clause having_clause
 				{
-					SubSelect *n = makeNode(SubSelect);
+					RetrieveStmt *n = makeNode(RetrieveStmt);
 					n->unique = $2;
 					n->unionall = FALSE;
 					n->targetList = $3;

src/include/nodes/parsenodes.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.38 1997/12/23 19:58:12 thomas Exp $
+ * $Id: parsenodes.h,v 1.39 1997/12/24 06:06:53 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,6 +58,8 @@ typedef struct Query
 	int			qry_numAgg;		/* number of aggregates in the target list */
 	Aggreg	  **qry_aggs;		/* the aggregates */
 
+	List	   *unionClause;	/* unions are linked under the previous query */
+
 	/* internal to planner */
 	List	   *base_relation_list_;	/* base relation list */
 	List	   *join_relation_list_;	/* list of relations */
@@ -634,28 +636,14 @@ typedef struct RetrieveStmt
 	Node	   *havingClause;	/* having conditional-expression */
 	List	   *unionClause;	/* union subselect parameters */
 	List	   *sortClause;		/* sort clause (a list of SortGroupBy's) */
+	int			unionall;		/* union without unique sort */
 } RetrieveStmt;
 
 
 /****************************************************************************
  *	Supporting data structures for Parse Trees
  ****************************************************************************/
 
-/*
- * SubSelect - specifies subselect parameters
- */
-typedef struct SubSelect
-{
-	NodeTag		type;
-	char	   *unique;			/* NULL, '*', or unique attribute name */
-	int			unionall;		/* union without unique sort */
-	List	   *targetList;		/* the target list (of ResTarget) */
-	List	   *fromClause;		/* the from clause */
-	Node	   *whereClause;	/* qualifications */
-	List	   *groupClause;	/* group by clause */
-	Node	   *havingClause;	/* having conditional-expression */
-} SubSelect;
-
 /*
  * TypeName - specifies a type in definitions
  */

src/include/optimizer/prep.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: prep.h,v 1.9 1997/12/20 07:59:44 momjian Exp $
+ * $Id: prep.h,v 1.10 1997/12/24 06:06:58 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,7 +32,7 @@ extern List *preprocess_targetlist(List *tlist, int command_type,
  */
 typedef enum UnionFlag
 {
-	INHERITS_FLAG, VERSION_FLAG
+	INHERITS_FLAG, UNION_FLAG, VERSION_FLAG
 } UnionFlag;
 
 extern List *find_all_inheritors(List *unexamined_relids,