From a19beb8922f57cb76084b751dda0047c3b2715da Mon Sep 17 00:00:00 2001
From: arnobrinkman <arnobrinkman@users.sourceforge.net>
Date: Thu, 14 Aug 2003 23:34:37 +0000
Subject: [PATCH] derived table support

---
 src/dsql/ddl.cpp |  8 ++++++--
 src/dsql/dsql.h  |  2 ++
 src/dsql/gen.cpp | 19 ++++++++++++++++---
 src/dsql/node.h  | 10 +++++++++-
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/src/dsql/ddl.cpp b/src/dsql/ddl.cpp
index 17db42ee77..4115d5af96 100644
--- a/src/dsql/ddl.cpp
+++ b/src/dsql/ddl.cpp
@@ -20,7 +20,7 @@
  * All Rights Reserved.
  * Contributor(s): ______________________________________.
  *
- * $Id: ddl.cpp,v 1.51 2003-08-06 16:30:38 skidder Exp $
+ * $Id: ddl.cpp,v 1.52 2003-08-14 23:31:13 arnobrinkman Exp $
  * 2001.5.20 Claudio Valderrama: Stop null pointer that leads to a crash,
  * caused by incomplete yacc syntax that allows ALTER DOMAIN dom SET;
  *
@@ -3394,12 +3394,16 @@ static void define_view( DSQL_REQ request, NOD_TYPE op)
 
 /* define the view source relations from the request contexts & union contexts*/
 
+    while (request->req_dt_context) {
+        context = reinterpret_cast<DSQL_CTX>(LLS_POP(&request->req_dt_context));
+        LLS_PUSH(context, &request->req_context);
+    }
+
     while (request->req_union_context) {
         context = reinterpret_cast<DSQL_CTX>(LLS_POP(&request->req_union_context));
         LLS_PUSH(context, &request->req_context);
     }
 
-
 	for (temp = request->req_context; temp; temp = temp->lls_next)
 	{
 		context = (DSQL_CTX) temp->lls_object;
diff --git a/src/dsql/dsql.h b/src/dsql/dsql.h
index dc368505ac..1ee1c66b1d 100644
--- a/src/dsql/dsql.h
+++ b/src/dsql/dsql.h
@@ -403,6 +403,7 @@ public:
 	DsqlMemoryPool*	req_pool;
 	DLLS	req_context;
     DLLS    req_union_context;	//!< Save contexts for views of unions
+    DLLS    req_dt_context;		//!< Save contexts for views of derived tables
 	struct sym* req_name;		//!< Name of request
 	struct sym* req_cursor;		//!< Cursor symbol, if any
 	dbb*	req_dbb;			//!< Database handle
@@ -443,6 +444,7 @@ public:
 	USHORT	req_error_handlers;	//!< count of active error handlers
 	USHORT	req_flags;			//!< generic flag
 	USHORT	req_client_dialect;	//!< dialect passed into the API call
+	USHORT	req_in_outer_join;	//!< processing inside outer-join part
 };
 typedef dsql_req* DSQL_REQ;
 
diff --git a/src/dsql/gen.cpp b/src/dsql/gen.cpp
index 78e83799cd..894fa683c0 100644
--- a/src/dsql/gen.cpp
+++ b/src/dsql/gen.cpp
@@ -29,7 +29,7 @@
  * 2002.10.29 Nickolay Samofatov: Added support for savepoints
  */
 /*
-$Id: gen.cpp,v 1.35 2003-08-14 07:11:24 fsg Exp $
+$Id: gen.cpp,v 1.36 2003-08-14 23:33:43 arnobrinkman Exp $
 */
 
 #include "firebird.h"
@@ -264,6 +264,10 @@ void GEN_expr( DSQL_REQ request, DSQL_NOD node)
 		gen_rse(request, node);
 		return;
 
+	case nod_derived_table:
+		gen_rse(request, node->nod_arg[e_derived_table_rse]);
+		return;
+
 	case nod_exists:
 		STUFF(blr_any);
 		gen_rse(request, node->nod_arg[0]);
@@ -2058,8 +2062,12 @@ static void gen_rse( DSQL_REQ request, DSQL_NOD rse)
 			 ptr++) {
 			DSQL_NOD node = *ptr;
 			if (node->nod_type == nod_relation ||
-				node->nod_type == nod_aggregate || node->nod_type == nod_join)
+				node->nod_type == nod_aggregate || node->nod_type == nod_join) {
 				GEN_expr(request, node);
+			}
+			else if (node->nod_type == nod_derived_table) {
+				GEN_expr(request, node->nod_arg[e_derived_table_rse]);
+			}
 		}
 	}
 	else {
@@ -2659,7 +2667,12 @@ static void gen_union( DSQL_REQ request, DSQL_NOD union_node)
 
 // Obtain the context for UNION from the first MAP node 
 	DSQL_NOD items = union_node->nod_arg[e_rse_items];
-	DSQL_CTX union_context = (DSQL_CTX) items->nod_arg[0]->nod_arg[e_map_context];
+	DSQL_NOD map_item = items->nod_arg[0];
+	// AB: First item could be a alias generated by derived table.
+	if (map_item->nod_type == nod_alias) {
+		map_item = map_item->nod_arg[e_alias_value]; 
+	}
+	DSQL_CTX union_context = (DSQL_CTX) map_item->nod_arg[e_map_context];
 	STUFF(union_context->ctx_context);
 
 	DSQL_NOD streams = union_node->nod_arg[e_rse_streams];
diff --git a/src/dsql/node.h b/src/dsql/node.h
index d4637c7ed5..b1cf0aef2e 100644
--- a/src/dsql/node.h
+++ b/src/dsql/node.h
@@ -333,7 +333,8 @@ typedef ENUM nod_t
 	nod_difference_file,
 	nod_drop_difference,
 	nod_begin_backup,
-	nod_end_backup
+	nod_end_backup,
+	nod_derived_table // Derived table support
 } NOD_TYPE;
 
 
@@ -382,6 +383,8 @@ typedef dsql_nod* DSQL_NOD;
 #define NOD_READ	4
 #define NOD_WRITE	8
 
+#define NOD_DERIVED_TABLE	1 // flag used by nod_alias
+
 #define REF_ACTION_CASCADE 1
 #define REF_ACTION_SET_DEFAULT 2
 #define REF_ACTION_SET_NULL 4
@@ -867,4 +870,9 @@ typedef dsql_nod* DSQL_NOD;
 #define e_searched_case_search_conditions	0	/* list boolean expressions */
 #define e_searched_case_results				1	/* list including else_result */
 
+#define e_derived_table_rse				0  // Contains select_expr
+#define e_derived_table_alias			1  // Alias name for derived table
+#define e_derived_table_column_alias	2  // List with alias names from derived table columns
+#define e_derived_table_count			3  
+
 #endif /* _DSQL_NODE_H_ */