mirror of
https://github.com/postgres/postgres.git
synced 2025-06-13 07:41:39 +03:00
Support window functions a la SQL:2008.
Hitoshi Harada, with some kibitzing from Heikki and Tom.
This commit is contained in:
Tom Lane
@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.290 2008/12/19 05:04:35 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.291 2008/12/28 18:53:59 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -81,6 +81,8 @@ typedef struct
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{
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StringInfo buf; /* output buffer to append to */
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List *namespaces; /* List of deparse_namespace nodes */
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List *windowClause; /* Current query level's WINDOW clause */
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List *windowTList; /* targetlist for resolving WINDOW clause */
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int prettyFlags; /* enabling of pretty-print functions */
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int indentLevel; /* current indent level for prettyprint */
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bool varprefix; /* TRUE to print prefixes on Vars */
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@ -167,6 +169,11 @@ static void get_setop_query(Node *setOp, Query *query,
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static Node *get_rule_sortgroupclause(SortGroupClause *srt, List *tlist,
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bool force_colno,
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deparse_context *context);
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static void get_rule_orderby(List *orderList, List *targetList,
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bool force_colno, deparse_context *context);
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static void get_rule_windowclause(Query *query, deparse_context *context);
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static void get_rule_windowspec(WindowClause *wc, List *targetList,
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deparse_context *context);
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static void push_plan(deparse_namespace *dpns, Plan *subplan);
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static char *get_variable(Var *var, int levelsup, bool showstar,
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deparse_context *context);
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@ -183,6 +190,7 @@ static void get_oper_expr(OpExpr *expr, deparse_context *context);
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static void get_func_expr(FuncExpr *expr, deparse_context *context,
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bool showimplicit);
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static void get_agg_expr(Aggref *aggref, deparse_context *context);
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static void get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context);
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static void get_coercion_expr(Node *arg, deparse_context *context,
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Oid resulttype, int32 resulttypmod,
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Node *parentNode);
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@ -1854,6 +1862,8 @@ deparse_expression_pretty(Node *expr, List *dpcontext,
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initStringInfo(&buf);
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context.buf = &buf;
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context.namespaces = dpcontext;
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context.windowClause = NIL;
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context.windowTList = NIL;
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context.varprefix = forceprefix;
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context.prettyFlags = prettyFlags;
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context.indentLevel = startIndent;
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@ -2085,6 +2095,8 @@ make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
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context.buf = buf;
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context.namespaces = list_make1(&dpns);
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context.windowClause = NIL;
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context.windowTList = NIL;
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context.varprefix = (list_length(query->rtable) != 1);
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context.prettyFlags = prettyFlags;
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context.indentLevel = PRETTYINDENT_STD;
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@ -2228,6 +2240,8 @@ get_query_def(Query *query, StringInfo buf, List *parentnamespace,
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context.buf = buf;
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context.namespaces = lcons(&dpns, list_copy(parentnamespace));
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context.windowClause = NIL;
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context.windowTList = NIL;
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context.varprefix = (parentnamespace != NIL ||
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list_length(query->rtable) != 1);
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context.prettyFlags = prettyFlags;
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@ -2392,13 +2406,20 @@ get_select_query_def(Query *query, deparse_context *context,
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TupleDesc resultDesc)
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{
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StringInfo buf = context->buf;
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List *save_windowclause;
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List *save_windowtlist;
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bool force_colno;
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const char *sep;
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ListCell *l;
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/* Insert the WITH clause if given */
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get_with_clause(query, context);
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/* Set up context for possible window functions */
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save_windowclause = context->windowClause;
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context->windowClause = query->windowClause;
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save_windowtlist = context->windowTList;
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context->windowTList = query->targetList;
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/*
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* If the Query node has a setOperations tree, then it's the top level of
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* a UNION/INTERSECT/EXCEPT query; only the WITH, ORDER BY and LIMIT
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@ -2421,48 +2442,8 @@ get_select_query_def(Query *query, deparse_context *context,
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{
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appendContextKeyword(context, " ORDER BY ",
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-PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
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sep = "";
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foreach(l, query->sortClause)
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{
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SortGroupClause *srt = (SortGroupClause *) lfirst(l);
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Node *sortexpr;
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Oid sortcoltype;
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TypeCacheEntry *typentry;
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appendStringInfoString(buf, sep);
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sortexpr = get_rule_sortgroupclause(srt, query->targetList,
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force_colno, context);
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sortcoltype = exprType(sortexpr);
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/* See whether operator is default < or > for datatype */
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typentry = lookup_type_cache(sortcoltype,
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TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
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if (srt->sortop == typentry->lt_opr)
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{
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/* ASC is default, so emit nothing for it */
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if (srt->nulls_first)
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appendStringInfo(buf, " NULLS FIRST");
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}
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else if (srt->sortop == typentry->gt_opr)
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{
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appendStringInfo(buf, " DESC");
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/* DESC defaults to NULLS FIRST */
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if (!srt->nulls_first)
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appendStringInfo(buf, " NULLS LAST");
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}
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else
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{
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appendStringInfo(buf, " USING %s",
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generate_operator_name(srt->sortop,
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sortcoltype,
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sortcoltype));
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/* be specific to eliminate ambiguity */
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if (srt->nulls_first)
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appendStringInfo(buf, " NULLS FIRST");
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else
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appendStringInfo(buf, " NULLS LAST");
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}
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sep = ", ";
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}
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get_rule_orderby(query->sortClause, query->targetList,
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force_colno, context);
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}
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/* Add the LIMIT clause if given */
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@ -2500,6 +2481,9 @@ get_select_query_def(Query *query, deparse_context *context,
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if (rc->noWait)
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appendStringInfo(buf, " NOWAIT");
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}
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context->windowClause = save_windowclause;
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context->windowTList = save_windowtlist;
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}
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static void
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@ -2603,6 +2587,10 @@ get_basic_select_query(Query *query, deparse_context *context,
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-PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
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get_rule_expr(query->havingQual, context, false);
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}
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/* Add the WINDOW clause if needed */
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if (query->windowClause != NIL)
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get_rule_windowclause(query, context);
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}
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/* ----------
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@ -2807,6 +2795,143 @@ get_rule_sortgroupclause(SortGroupClause *srt, List *tlist, bool force_colno,
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return expr;
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}
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/*
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* Display an ORDER BY list.
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*/
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static void
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get_rule_orderby(List *orderList, List *targetList,
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bool force_colno, deparse_context *context)
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{
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StringInfo buf = context->buf;
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const char *sep;
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ListCell *l;
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sep = "";
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foreach(l, orderList)
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{
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SortGroupClause *srt = (SortGroupClause *) lfirst(l);
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Node *sortexpr;
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Oid sortcoltype;
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TypeCacheEntry *typentry;
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appendStringInfoString(buf, sep);
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sortexpr = get_rule_sortgroupclause(srt, targetList,
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force_colno, context);
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sortcoltype = exprType(sortexpr);
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/* See whether operator is default < or > for datatype */
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typentry = lookup_type_cache(sortcoltype,
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TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
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if (srt->sortop == typentry->lt_opr)
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{
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/* ASC is default, so emit nothing for it */
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if (srt->nulls_first)
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appendStringInfo(buf, " NULLS FIRST");
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}
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else if (srt->sortop == typentry->gt_opr)
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{
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appendStringInfo(buf, " DESC");
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/* DESC defaults to NULLS FIRST */
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if (!srt->nulls_first)
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appendStringInfo(buf, " NULLS LAST");
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}
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else
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{
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appendStringInfo(buf, " USING %s",
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generate_operator_name(srt->sortop,
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sortcoltype,
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sortcoltype));
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/* be specific to eliminate ambiguity */
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if (srt->nulls_first)
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appendStringInfo(buf, " NULLS FIRST");
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else
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appendStringInfo(buf, " NULLS LAST");
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}
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sep = ", ";
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}
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}
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/*
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* Display a WINDOW clause.
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*
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* Note that the windowClause list might contain only anonymous window
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* specifications, in which case we should print nothing here.
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*/
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static void
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get_rule_windowclause(Query *query, deparse_context *context)
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{
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StringInfo buf = context->buf;
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const char *sep;
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ListCell *l;
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sep = NULL;
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foreach(l, query->windowClause)
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{
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WindowClause *wc = (WindowClause *) lfirst(l);
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if (wc->name == NULL)
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continue; /* ignore anonymous windows */
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if (sep == NULL)
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appendContextKeyword(context, " WINDOW ",
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-PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
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else
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appendStringInfoString(buf, sep);
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appendStringInfo(buf, "%s AS ", quote_identifier(wc->name));
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get_rule_windowspec(wc, query->targetList, context);
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sep = ", ";
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}
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}
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/*
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* Display a window definition
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*/
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static void
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get_rule_windowspec(WindowClause *wc, List *targetList,
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deparse_context *context)
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{
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StringInfo buf = context->buf;
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bool needspace = false;
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const char *sep;
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ListCell *l;
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appendStringInfoChar(buf, '(');
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if (wc->refname)
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{
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appendStringInfoString(buf, quote_identifier(wc->refname));
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needspace = true;
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}
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/* partitions are always inherited, so only print if no refname */
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if (wc->partitionClause && !wc->refname)
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{
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if (needspace)
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appendStringInfoChar(buf, ' ');
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appendStringInfoString(buf, "PARTITION BY ");
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sep = "";
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foreach(l, wc->partitionClause)
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{
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SortGroupClause *grp = (SortGroupClause *) lfirst(l);
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appendStringInfoString(buf, sep);
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get_rule_sortgroupclause(grp, targetList,
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false, context);
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sep = ", ";
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}
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needspace = true;
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}
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if (wc->orderClause && !wc->copiedOrder)
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{
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if (needspace)
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appendStringInfoChar(buf, ' ');
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appendStringInfoString(buf, "ORDER BY ");
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get_rule_orderby(wc->orderClause, targetList, false, context);
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needspace = true;
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}
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appendStringInfoChar(buf, ')');
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}
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/* ----------
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* get_insert_query_def - Parse back an INSERT parsetree
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* ----------
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@ -3801,6 +3926,7 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
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case T_XmlExpr:
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case T_NullIfExpr:
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case T_Aggref:
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case T_WindowFunc:
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case T_FuncExpr:
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/* function-like: name(..) or name[..] */
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return true;
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@ -3916,6 +4042,7 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
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case T_XmlExpr: /* own parentheses */
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case T_NullIfExpr: /* other separators */
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case T_Aggref: /* own parentheses */
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case T_WindowFunc: /* own parentheses */
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case T_CaseExpr: /* other separators */
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return true;
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default:
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@ -3965,6 +4092,7 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
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case T_XmlExpr: /* own parentheses */
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case T_NullIfExpr: /* other separators */
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case T_Aggref: /* own parentheses */
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case T_WindowFunc: /* own parentheses */
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case T_CaseExpr: /* other separators */
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return true;
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default:
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@ -4093,6 +4221,10 @@ get_rule_expr(Node *node, deparse_context *context,
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get_agg_expr((Aggref *) node, context);
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break;
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case T_WindowFunc:
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get_windowfunc_expr((WindowFunc *) node, context);
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break;
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case T_ArrayRef:
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{
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ArrayRef *aref = (ArrayRef *) node;
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@ -4999,13 +5131,13 @@ get_func_expr(FuncExpr *expr, deparse_context *context,
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* Normal function: display as proname(args). First we need to extract
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* the argument datatypes.
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*/
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if (list_length(expr->args) > FUNC_MAX_ARGS)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
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errmsg("too many arguments")));
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nargs = 0;
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foreach(l, expr->args)
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{
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if (nargs >= FUNC_MAX_ARGS)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
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errmsg("too many arguments")));
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argtypes[nargs] = exprType((Node *) lfirst(l));
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nargs++;
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}
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@ -5036,13 +5168,13 @@ get_agg_expr(Aggref *aggref, deparse_context *context)
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int nargs;
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ListCell *l;
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if (list_length(aggref->args) > FUNC_MAX_ARGS)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
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errmsg("too many arguments")));
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nargs = 0;
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foreach(l, aggref->args)
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{
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if (nargs >= FUNC_MAX_ARGS)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
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errmsg("too many arguments")));
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argtypes[nargs] = exprType((Node *) lfirst(l));
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nargs++;
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}
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@ -5059,6 +5191,64 @@ get_agg_expr(Aggref *aggref, deparse_context *context)
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appendStringInfoChar(buf, ')');
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}
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/*
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* get_windowfunc_expr - Parse back a WindowFunc node
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*/
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static void
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get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
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{
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StringInfo buf = context->buf;
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Oid argtypes[FUNC_MAX_ARGS];
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int nargs;
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ListCell *l;
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if (list_length(wfunc->args) > FUNC_MAX_ARGS)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
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errmsg("too many arguments")));
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nargs = 0;
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foreach(l, wfunc->args)
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{
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argtypes[nargs] = exprType((Node *) lfirst(l));
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nargs++;
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}
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appendStringInfo(buf, "%s(%s",
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generate_function_name(wfunc->winfnoid,
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nargs, argtypes, NULL), "");
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/* winstar can be set only in zero-argument aggregates */
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if (wfunc->winstar)
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appendStringInfoChar(buf, '*');
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else
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get_rule_expr((Node *) wfunc->args, context, true);
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appendStringInfoString(buf, ") OVER ");
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foreach(l, context->windowClause)
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{
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WindowClause *wc = (WindowClause *) lfirst(l);
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if (wc->winref == wfunc->winref)
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{
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if (wc->name)
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appendStringInfoString(buf, quote_identifier(wc->name));
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else
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get_rule_windowspec(wc, context->windowTList, context);
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break;
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}
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}
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if (l == NULL)
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{
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if (context->windowClause)
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elog(ERROR, "could not find window clause for winref %u",
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wfunc->winref);
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/*
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* In EXPLAIN, we don't have window context information available,
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* so we have to settle for this:
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*/
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appendStringInfoString(buf, "(?)");
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}
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}
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/* ----------
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* get_coercion_expr
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*
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@ -6089,7 +6279,9 @@ generate_function_name(Oid funcid, int nargs, Oid *argtypes,
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NIL, nargs, argtypes, false, true,
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&p_funcid, &p_rettype,
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&p_retset, &p_nvargs, &p_true_typeids, NULL);
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if ((p_result == FUNCDETAIL_NORMAL || p_result == FUNCDETAIL_AGGREGATE) &&
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if ((p_result == FUNCDETAIL_NORMAL ||
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p_result == FUNCDETAIL_AGGREGATE ||
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p_result == FUNCDETAIL_WINDOWFUNC) &&
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p_funcid == funcid)
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nspname = NULL;
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else
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