Support window functions a la SQL:2008.

Hitoshi Harada, with some kibitzing from Heikki and Tom.

4 files changed, 25 insertions, 7 deletions

diff --git a/src/include/parser/parse_agg.h b/src/include/parser/parse_agg.h
index bf3574e89f..93b7f674e3 100644
--- a/src/include/parser/parse_agg.h
+++ b/src/include/parser/parse_agg.h
@@ -1,12 +1,12 @@
 /*-------------------------------------------------------------------------
  *
  * parse_agg.h
- *	  handle aggregates in parser
+ *	  handle aggregates and window functions in parser
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_agg.h,v 1.36 2008/01/01 19:45:58 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_agg.h,v 1.37 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,8 +16,11 @@
 #include "parser/parse_node.h"
 
 extern void transformAggregateCall(ParseState *pstate, Aggref *agg);
+extern void transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
+									WindowDef *windef);
 
 extern void parseCheckAggregates(ParseState *pstate, Query *qry);
+extern void parseCheckWindowFuncs(ParseState *pstate, Query *qry);
 
 extern void build_aggregate_fnexprs(Oid *agg_input_types,
 						int agg_num_inputs,
diff --git a/src/include/parser/parse_clause.h b/src/include/parser/parse_clause.h
index ffea3466b5..0463e7ae66 100644
--- a/src/include/parser/parse_clause.h
+++ b/src/include/parser/parse_clause.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_clause.h,v 1.52 2008/08/07 01:11:52 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_clause.h,v 1.53 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,9 +27,15 @@ extern Node *transformWhereClause(ParseState *pstate, Node *clause,
 extern Node *transformLimitClause(ParseState *pstate, Node *clause,
 					 const char *constructName);
 extern List *transformGroupClause(ParseState *pstate, List *grouplist,
-					 List **targetlist, List *sortClause);
+					 List **targetlist, List *sortClause,
+					 bool isPartition);
 extern List *transformSortClause(ParseState *pstate, List *orderlist,
 					List **targetlist, bool resolveUnknown);
+
+extern List *transformWindowDefinitions(ParseState *pstate,
+										List *windowdefs,
+										List **targetlist);
+
 extern List *transformDistinctClause(ParseState *pstate,
 						List **targetlist, List *sortClause);
 extern List *transformDistinctOnClause(ParseState *pstate, List *distinctlist,
diff --git a/src/include/parser/parse_func.h b/src/include/parser/parse_func.h
index 8507a4ed7d..b7023bf8d3 100644
--- a/src/include/parser/parse_func.h
+++ b/src/include/parser/parse_func.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.62 2008/12/18 18:20:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.63 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -37,6 +37,7 @@ typedef enum
 	FUNCDETAIL_MULTIPLE,		/* too many matching functions */
 	FUNCDETAIL_NORMAL,			/* found a matching regular function */
 	FUNCDETAIL_AGGREGATE,		/* found a matching aggregate function */
+	FUNCDETAIL_WINDOWFUNC,		/* found a matching window function */
 	FUNCDETAIL_COERCION			/* it's a type coercion request */
 } FuncDetailCode;
 
@@ -44,7 +45,7 @@ typedef enum
 extern Node *ParseFuncOrColumn(ParseState *pstate,
 				  List *funcname, List *fargs,
 				  bool agg_star, bool agg_distinct, bool func_variadic,
-				  bool is_column, int location);
+				  WindowDef *over, bool is_column, int location);
 
 extern FuncDetailCode func_get_detail(List *funcname, List *fargs,
 				int nargs, Oid *argtypes,
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 8e0d3c201f..0abe45df32 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.58 2008/10/08 01:14:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.59 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,6 +57,12 @@
  * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet
  * visible due to scope rules.  This is used to help improve error messages.
  *
+ * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses.
+ * We collect these while transforming expressions and then transform them
+ * afterwards (so that any resjunk tlist items needed for the sort/group
+ * clauses end up at the end of the query tlist).  A WindowDef's location in
+ * this list, counting from 1, is the winref number to use to reference it.
+ *
  * p_paramtypes: an array of p_numparams type OIDs for $n parameter symbols
  * (zeroth entry in array corresponds to $1).  If p_variableparams is true, the
  * set of param types is not predetermined; in that case, a zero array entry
@@ -77,6 +83,7 @@ typedef struct ParseState
 	List	   *p_varnamespace; /* current namespace for columns */
 	List	   *p_ctenamespace; /* current namespace for common table exprs */
 	List	   *p_future_ctes;	/* common table exprs not yet in namespace */
+	List	   *p_windowdefs;	/* raw representations of window clauses */
 	Oid		   *p_paramtypes;	/* OIDs of types for $n parameter symbols */
 	int			p_numparams;	/* allocated size of p_paramtypes[] */
 	int			p_next_resno;	/* next targetlist resno to assign */
@@ -84,6 +91,7 @@ typedef struct ParseState
 	Node	   *p_value_substitute;		/* what to replace VALUE with, if any */
 	bool		p_variableparams;
 	bool		p_hasAggs;
+	bool		p_hasWindowFuncs;
 	bool		p_hasSubLinks;
 	bool		p_is_insert;
 	bool		p_is_update;