/*------------------------------------------------------------------------- * * parse_agg.c * handle aggregates and window functions in parser * * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/parser/parse_agg.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "catalog/pg_aggregate.h" #include "catalog/pg_constraint.h" #include "catalog/pg_type.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "optimizer/tlist.h" #include "parser/parse_agg.h" #include "parser/parse_clause.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parsetree.h" #include "rewrite/rewriteManip.h" #include "utils/builtins.h" #include "utils/lsyscache.h" typedef struct { ParseState *pstate; int min_varlevel; int min_agglevel; int sublevels_up; } check_agg_arguments_context; typedef struct { ParseState *pstate; Query *qry; List *groupClauses; bool have_non_var_grouping; List **func_grouped_rels; int sublevels_up; bool in_agg_direct_args; } check_ungrouped_columns_context; static int check_agg_arguments(ParseState *pstate, List *directargs, List *args, Expr *filter); static bool check_agg_arguments_walker(Node *node, check_agg_arguments_context *context); static void check_ungrouped_columns(Node *node, ParseState *pstate, Query *qry, List *groupClauses, bool have_non_var_grouping, List **func_grouped_rels); static bool check_ungrouped_columns_walker(Node *node, check_ungrouped_columns_context *context); /* * transformAggregateCall - * Finish initial transformation of an aggregate call * * parse_func.c has recognized the function as an aggregate, and has set up * all the fields of the Aggref except aggdirectargs, args, aggorder, * aggdistinct and agglevelsup. The passed-in args list has been through * standard expression transformation and type coercion to match the agg's * declared arg types, while the passed-in aggorder list hasn't been * transformed at all. * * Here we separate the args list into direct and aggregated args, storing the * former in agg->aggdirectargs and the latter in agg->args. The regular * args, but not the direct args, are converted into a targetlist by inserting * TargetEntry nodes. We then transform the aggorder and agg_distinct * specifications to produce lists of SortGroupClause nodes for agg->aggorder * and agg->aggdistinct. (For a regular aggregate, this might result in * adding resjunk expressions to the targetlist; but for ordered-set * aggregates the aggorder list will always be one-to-one with the aggregated * args.) * * We must also determine which query level the aggregate actually belongs to, * set agglevelsup accordingly, and mark p_hasAggs true in the corresponding * pstate level. */ void transformAggregateCall(ParseState *pstate, Aggref *agg, List *args, List *aggorder, bool agg_distinct) { List *tlist = NIL; List *torder = NIL; List *tdistinct = NIL; AttrNumber attno = 1; int save_next_resno; int min_varlevel; ListCell *lc; const char *err; bool errkind; if (AGGKIND_IS_ORDERED_SET(agg->aggkind)) { /* * For an ordered-set agg, the args list includes direct args and * aggregated args; we must split them apart. */ int numDirectArgs = list_length(args) - list_length(aggorder); List *aargs; ListCell *lc2; Assert(numDirectArgs >= 0); aargs = list_copy_tail(args, numDirectArgs); agg->aggdirectargs = list_truncate(args, numDirectArgs); /* * Build a tlist from the aggregated args, and make a sortlist entry * for each one. Note that the expressions in the SortBy nodes are * ignored (they are the raw versions of the transformed args); we are * just looking at the sort information in the SortBy nodes. */ forboth(lc, aargs, lc2, aggorder) { Expr *arg = (Expr *) lfirst(lc); SortBy *sortby = (SortBy *) lfirst(lc2); TargetEntry *tle; /* We don't bother to assign column names to the entries */ tle = makeTargetEntry(arg, attno++, NULL, false); tlist = lappend(tlist, tle); torder = addTargetToSortList(pstate, tle, torder, tlist, sortby, true /* fix unknowns */ ); } /* Never any DISTINCT in an ordered-set agg */ Assert(!agg_distinct); } else { /* Regular aggregate, so it has no direct args */ agg->aggdirectargs = NIL; /* * Transform the plain list of Exprs into a targetlist. */ foreach(lc, args) { Expr *arg = (Expr *) lfirst(lc); TargetEntry *tle; /* We don't bother to assign column names to the entries */ tle = makeTargetEntry(arg, attno++, NULL, false); tlist = lappend(tlist, tle); } /* * If we have an ORDER BY, transform it. This will add columns to the * tlist if they appear in ORDER BY but weren't already in the arg * list. They will be marked resjunk = true so we can tell them apart * from regular aggregate arguments later. * * We need to mess with p_next_resno since it will be used to number * any new targetlist entries. */ save_next_resno = pstate->p_next_resno; pstate->p_next_resno = attno; torder = transformSortClause(pstate, aggorder, &tlist, EXPR_KIND_ORDER_BY, true /* fix unknowns */ , true /* force SQL99 rules */ ); /* * If we have DISTINCT, transform that to produce a distinctList. */ if (agg_distinct) { tdistinct = transformDistinctClause(pstate, &tlist, torder, true); /* * Remove this check if executor support for hashed distinct for * aggregates is ever added. */ foreach(lc, tdistinct) { SortGroupClause *sortcl = (SortGroupClause *) lfirst(lc); if (!OidIsValid(sortcl->sortop)) { Node *expr = get_sortgroupclause_expr(sortcl, tlist); ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), errmsg("could not identify an ordering operator for type %s", format_type_be(exprType(expr))), errdetail("Aggregates with DISTINCT must be able to sort their inputs."), parser_errposition(pstate, exprLocation(expr)))); } } } pstate->p_next_resno = save_next_resno; } /* Update the Aggref with the transformation results */ agg->args = tlist; agg->aggorder = torder; agg->aggdistinct = tdistinct; /* * Check the arguments to compute the aggregate's level and detect * improper nesting. */ min_varlevel = check_agg_arguments(pstate, agg->aggdirectargs, agg->args, agg->aggfilter); agg->agglevelsup = min_varlevel; /* Mark the correct pstate level as having aggregates */ while (min_varlevel-- > 0) pstate = pstate->parentParseState; pstate->p_hasAggs = true; /* * Check to see if the aggregate function is in an invalid place within * its aggregation query. * * For brevity we support two schemes for reporting an error here: set * "err" to a custom message, or set "errkind" true if the error context * is sufficiently identified by what ParseExprKindName will return, *and* * what it will return is just a SQL keyword. (Otherwise, use a custom * message to avoid creating translation problems.) */ err = NULL; errkind = false; switch (pstate->p_expr_kind) { case EXPR_KIND_NONE: Assert(false); /* can't happen */ break; case EXPR_KIND_OTHER: /* Accept aggregate here; caller must throw error if wanted */ break; case EXPR_KIND_JOIN_ON: case EXPR_KIND_JOIN_USING: err = _("aggregate functions are not allowed in JOIN conditions"); break; case EXPR_KIND_FROM_SUBSELECT: /* Should only be possible in a LATERAL subquery */ Assert(pstate->p_lateral_active); /* Aggregate scope rules make it worth being explicit here */ err = _("aggregate functions are not allowed in FROM clause of their own query level"); break; case EXPR_KIND_FROM_FUNCTION: err = _("aggregate functions are not allowed in functions in FROM"); break; case EXPR_KIND_WHERE: errkind = true; break; case EXPR_KIND_HAVING: /* okay */ break; case EXPR_KIND_FILTER: errkind = true; break; case EXPR_KIND_WINDOW_PARTITION: /* okay */ break; case EXPR_KIND_WINDOW_ORDER: /* okay */ break; case EXPR_KIND_WINDOW_FRAME_RANGE: err = _("aggregate functions are not allowed in window RANGE"); break; case EXPR_KIND_WINDOW_FRAME_ROWS: err = _("aggregate functions are not allowed in window ROWS"); break; case EXPR_KIND_SELECT_TARGET: /* okay */ break; case EXPR_KIND_INSERT_TARGET: case EXPR_KIND_UPDATE_SOURCE: case EXPR_KIND_UPDATE_TARGET: errkind = true; break; case EXPR_KIND_GROUP_BY: errkind = true; break; case EXPR_KIND_ORDER_BY: /* okay */ break; case EXPR_KIND_DISTINCT_ON: /* okay */ break; case EXPR_KIND_LIMIT: case EXPR_KIND_OFFSET: errkind = true; break; case EXPR_KIND_RETURNING: errkind = true; break; case EXPR_KIND_VALUES: errkind = true; break; case EXPR_KIND_CHECK_CONSTRAINT: case EXPR_KIND_DOMAIN_CHECK: err = _("aggregate functions are not allowed in check constraints"); break; case EXPR_KIND_COLUMN_DEFAULT: case EXPR_KIND_FUNCTION_DEFAULT: err = _("aggregate functions are not allowed in DEFAULT expressions"); break; case EXPR_KIND_INDEX_EXPRESSION: err = _("aggregate functions are not allowed in index expressions"); break; case EXPR_KIND_INDEX_PREDICATE: err = _("aggregate functions are not allowed in index predicates"); break; case EXPR_KIND_ALTER_COL_TRANSFORM: err = _("aggregate functions are not allowed in transform expressions"); break; case EXPR_KIND_EXECUTE_PARAMETER: err = _("aggregate functions are not allowed in EXECUTE parameters"); break; case EXPR_KIND_TRIGGER_WHEN: err = _("aggregate functions are not allowed in trigger WHEN conditions"); break; /* * There is intentionally no default: case here, so that the * compiler will warn if we add a new ParseExprKind without * extending this switch. If we do see an unrecognized value at * runtime, the behavior will be the same as for EXPR_KIND_OTHER, * which is sane anyway. */ } if (err) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg_internal("%s", err), parser_errposition(pstate, agg->location))); if (errkind) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), /* translator: %s is name of a SQL construct, eg GROUP BY */ errmsg("aggregate functions are not allowed in %s", ParseExprKindName(pstate->p_expr_kind)), parser_errposition(pstate, agg->location))); } /* * check_agg_arguments * Scan the arguments of an aggregate function to determine the * aggregate's semantic level (zero is the current select's level, * one is its parent, etc). * * The aggregate's level is the same as the level of the lowest-level variable * or aggregate in its aggregated arguments (including any ORDER BY columns) * or filter expression; or if it contains no variables at all, we presume it * to be local. * * Vars/Aggs in direct arguments are *not* counted towards determining the * agg's level, as those arguments aren't evaluated per-row but only * per-group, and so in some sense aren't really agg arguments. However, * this can mean that we decide an agg is upper-level even when its direct * args contain lower-level Vars/Aggs, and that case has to be disallowed. * (This is a little strange, but the SQL standard seems pretty definite that * direct args are not to be considered when setting the agg's level.) * * We also take this opportunity to detect any aggregates or window functions * nested within the arguments. We can throw error immediately if we find * a window function. Aggregates are a bit trickier because it's only an * error if the inner aggregate is of the same semantic level as the outer, * which we can't know until we finish scanning the arguments. */ static int check_agg_arguments(ParseState *pstate, List *directargs, List *args, Expr *filter) { int agglevel; check_agg_arguments_context context; context.pstate = pstate; context.min_varlevel = -1; /* signifies nothing found yet */ context.min_agglevel = -1; context.sublevels_up = 0; (void) expression_tree_walker((Node *) args, check_agg_arguments_walker, (void *) &context); (void) expression_tree_walker((Node *) filter, check_agg_arguments_walker, (void *) &context); /* * If we found no vars nor aggs at all, it's a level-zero aggregate; * otherwise, its level is the minimum of vars or aggs. */ if (context.min_varlevel < 0) { if (context.min_agglevel < 0) agglevel = 0; else agglevel = context.min_agglevel; } else if (context.min_agglevel < 0) agglevel = context.min_varlevel; else agglevel = Min(context.min_varlevel, context.min_agglevel); /* * If there's a nested aggregate of the same semantic level, complain. */ if (agglevel == context.min_agglevel) { int aggloc; aggloc = locate_agg_of_level((Node *) args, agglevel); if (aggloc < 0) aggloc = locate_agg_of_level((Node *) filter, agglevel); ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("aggregate function calls cannot be nested"), parser_errposition(pstate, aggloc))); } /* * Now check for vars/aggs in the direct arguments, and throw error if * needed. Note that we allow a Var of the agg's semantic level, but not * an Agg of that level. In principle such Aggs could probably be * supported, but it would create an ordering dependency among the * aggregates at execution time. Since the case appears neither to be * required by spec nor particularly useful, we just treat it as a * nested-aggregate situation. */ if (directargs) { context.min_varlevel = -1; context.min_agglevel = -1; (void) expression_tree_walker((Node *) directargs, check_agg_arguments_walker, (void *) &context); if (context.min_varlevel >= 0 && context.min_varlevel < agglevel) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("outer-level aggregate cannot contain a lower-level variable in its direct arguments"), parser_errposition(pstate, locate_var_of_level((Node *) directargs, context.min_varlevel)))); if (context.min_agglevel >= 0 && context.min_agglevel <= agglevel) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("aggregate function calls cannot be nested"), parser_errposition(pstate, locate_agg_of_level((Node *) directargs, context.min_agglevel)))); } return agglevel; } static bool check_agg_arguments_walker(Node *node, check_agg_arguments_context *context) { if (node == NULL) return false; if (IsA(node, Var)) { int varlevelsup = ((Var *) node)->varlevelsup; /* convert levelsup to frame of reference of original query */ varlevelsup -= context->sublevels_up; /* ignore local vars of subqueries */ if (varlevelsup >= 0) { if (context->min_varlevel < 0 || context->min_varlevel > varlevelsup) context->min_varlevel = varlevelsup; } return false; } if (IsA(node, Aggref)) { int agglevelsup = ((Aggref *) node)->agglevelsup; /* convert levelsup to frame of reference of original query */ agglevelsup -= context->sublevels_up; /* ignore local aggs of subqueries */ if (agglevelsup >= 0) { if (context->min_agglevel < 0 || context->min_agglevel > agglevelsup) context->min_agglevel = agglevelsup; } /* no need to examine args of the inner aggregate */ return false; } /* We can throw error on sight for a window function */ if (IsA(node, WindowFunc)) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("aggregate function calls cannot contain window function calls"), parser_errposition(context->pstate, ((WindowFunc *) node)->location))); if (IsA(node, Query)) { /* Recurse into subselects */ bool result; context->sublevels_up++; result = query_tree_walker((Query *) node, check_agg_arguments_walker, (void *) context, 0); context->sublevels_up--; return result; } return expression_tree_walker(node, check_agg_arguments_walker, (void *) context); } /* * transformWindowFuncCall - * Finish initial transformation of a window function call * * parse_func.c has recognized the function as a window function, and has set * up all the fields of the WindowFunc except winref. Here we must (1) add * the WindowDef to the pstate (if not a duplicate of one already present) and * set winref to link to it; and (2) mark p_hasWindowFuncs true in the pstate. * Unlike aggregates, only the most closely nested pstate level need be * considered --- there are no "outer window functions" per SQL spec. */ void transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc, WindowDef *windef) { const char *err; bool errkind; /* * A window function call can't contain another one (but aggs are OK). XXX * is this required by spec, or just an unimplemented feature? * * Note: we don't need to check the filter expression here, because the * context checks done below and in transformAggregateCall would have * already rejected any window funcs or aggs within the filter. */ if (pstate->p_hasWindowFuncs && contain_windowfuncs((Node *) wfunc->args)) ereport(ERROR, (errcode(ERRCODE_WINDOWING_ERROR), errmsg("window function calls cannot be nested"), parser_errposition(pstate, locate_windowfunc((Node *) wfunc->args)))); /* * Check to see if the window function is in an invalid place within the * query. * * For brevity we support two schemes for reporting an error here: set * "err" to a custom message, or set "errkind" true if the error context * is sufficiently identified by what ParseExprKindName will return, *and* * what it will return is just a SQL keyword. (Otherwise, use a custom * message to avoid creating translation problems.) */ err = NULL; errkind = false; switch (pstate->p_expr_kind) { case EXPR_KIND_NONE: Assert(false); /* can't happen */ break; case EXPR_KIND_OTHER: /* Accept window func here; caller must throw error if wanted */ break; case EXPR_KIND_JOIN_ON: case EXPR_KIND_JOIN_USING: err = _("window functions are not allowed in JOIN conditions"); break; case EXPR_KIND_FROM_SUBSELECT: /* can't get here, but just in case, throw an error */ errkind = true; break; case EXPR_KIND_FROM_FUNCTION: err = _("window functions are not allowed in functions in FROM"); break; case EXPR_KIND_WHERE: errkind = true; break; case EXPR_KIND_HAVING: errkind = true; break; case EXPR_KIND_FILTER: errkind = true; break; case EXPR_KIND_WINDOW_PARTITION: case EXPR_KIND_WINDOW_ORDER: case EXPR_KIND_WINDOW_FRAME_RANGE: case EXPR_KIND_WINDOW_FRAME_ROWS: err = _("window functions are not allowed in window definitions"); break; case EXPR_KIND_SELECT_TARGET: /* okay */ break; case EXPR_KIND_INSERT_TARGET: case EXPR_KIND_UPDATE_SOURCE: case EXPR_KIND_UPDATE_TARGET: errkind = true; break; case EXPR_KIND_GROUP_BY: errkind = true; break; case EXPR_KIND_ORDER_BY: /* okay */ break; case EXPR_KIND_DISTINCT_ON: /* okay */ break; case EXPR_KIND_LIMIT: case EXPR_KIND_OFFSET: errkind = true; break; case EXPR_KIND_RETURNING: errkind = true; break; case EXPR_KIND_VALUES: errkind = true; break; case EXPR_KIND_CHECK_CONSTRAINT: case EXPR_KIND_DOMAIN_CHECK: err = _("window functions are not allowed in check constraints"); break; case EXPR_KIND_COLUMN_DEFAULT: case EXPR_KIND_FUNCTION_DEFAULT: err = _("window functions are not allowed in DEFAULT expressions"); break; case EXPR_KIND_INDEX_EXPRESSION: err = _("window functions are not allowed in index expressions"); break; case EXPR_KIND_INDEX_PREDICATE: err = _("window functions are not allowed in index predicates"); break; case EXPR_KIND_ALTER_COL_TRANSFORM: err = _("window functions are not allowed in transform expressions"); break; case EXPR_KIND_EXECUTE_PARAMETER: err = _("window functions are not allowed in EXECUTE parameters"); break; case EXPR_KIND_TRIGGER_WHEN: err = _("window functions are not allowed in trigger WHEN conditions"); break; /* * There is intentionally no default: case here, so that the * compiler will warn if we add a new ParseExprKind without * extending this switch. If we do see an unrecognized value at * runtime, the behavior will be the same as for EXPR_KIND_OTHER, * which is sane anyway. */ } if (err) ereport(ERROR, (errcode(ERRCODE_WINDOWING_ERROR), errmsg_internal("%s", err), parser_errposition(pstate, wfunc->location))); if (errkind) ereport(ERROR, (errcode(ERRCODE_WINDOWING_ERROR), /* translator: %s is name of a SQL construct, eg GROUP BY */ errmsg("window functions are not allowed in %s", ParseExprKindName(pstate->p_expr_kind)), parser_errposition(pstate, wfunc->location))); /* * If the OVER clause just specifies a window name, find that WINDOW * clause (which had better be present). Otherwise, try to match all the * properties of the OVER clause, and make a new entry in the p_windowdefs * list if no luck. */ if (windef->name) { Index winref = 0; ListCell *lc; Assert(windef->refname == NULL && windef->partitionClause == NIL && windef->orderClause == NIL && windef->frameOptions == FRAMEOPTION_DEFAULTS); foreach(lc, pstate->p_windowdefs) { WindowDef *refwin = (WindowDef *) lfirst(lc); winref++; if (refwin->name && strcmp(refwin->name, windef->name) == 0) { wfunc->winref = winref; break; } } if (lc == NULL) /* didn't find it? */ ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("window \"%s\" does not exist", windef->name), parser_errposition(pstate, windef->location))); } else { Index winref = 0; ListCell *lc; foreach(lc, pstate->p_windowdefs) { WindowDef *refwin = (WindowDef *) lfirst(lc); winref++; if (refwin->refname && windef->refname && strcmp(refwin->refname, windef->refname) == 0) /* matched on refname */ ; else if (!refwin->refname && !windef->refname) /* matched, no refname */ ; else continue; if (equal(refwin->partitionClause, windef->partitionClause) && equal(refwin->orderClause, windef->orderClause) && refwin->frameOptions == windef->frameOptions && equal(refwin->startOffset, windef->startOffset) && equal(refwin->endOffset, windef->endOffset)) { /* found a duplicate window specification */ wfunc->winref = winref; break; } } if (lc == NULL) /* didn't find it? */ { pstate->p_windowdefs = lappend(pstate->p_windowdefs, windef); wfunc->winref = list_length(pstate->p_windowdefs); } } pstate->p_hasWindowFuncs = true; } /* * parseCheckAggregates * Check for aggregates where they shouldn't be and improper grouping. * This function should be called after the target list and qualifications * are finalized. * * Misplaced aggregates are now mostly detected in transformAggregateCall, * but it seems more robust to check for aggregates in recursive queries * only after everything is finalized. In any case it's hard to detect * improper grouping on-the-fly, so we have to make another pass over the * query for that. */ void parseCheckAggregates(ParseState *pstate, Query *qry) { List *groupClauses = NIL; bool have_non_var_grouping; List *func_grouped_rels = NIL; ListCell *l; bool hasJoinRTEs; bool hasSelfRefRTEs; PlannerInfo *root; Node *clause; /* This should only be called if we found aggregates or grouping */ Assert(pstate->p_hasAggs || qry->groupClause || qry->havingQual); /* * Scan the range table to see if there are JOIN or self-reference CTE * entries. We'll need this info below. */ hasJoinRTEs = hasSelfRefRTEs = false; foreach(l, pstate->p_rtable) { RangeTblEntry *rte = (RangeTblEntry *) lfirst(l); if (rte->rtekind == RTE_JOIN) hasJoinRTEs = true; else if (rte->rtekind == RTE_CTE && rte->self_reference) hasSelfRefRTEs = true; } /* * Build a list of the acceptable GROUP BY expressions for use by * check_ungrouped_columns(). */ foreach(l, qry->groupClause) { SortGroupClause *grpcl = (SortGroupClause *) lfirst(l); Node *expr; expr = get_sortgroupclause_expr(grpcl, qry->targetList); if (expr == NULL) continue; /* probably cannot happen */ groupClauses = lcons(expr, groupClauses); } /* * If there are join alias vars involved, we have to flatten them to the * underlying vars, so that aliased and unaliased vars will be correctly * taken as equal. We can skip the expense of doing this if no rangetable * entries are RTE_JOIN kind. We use the planner's flatten_join_alias_vars * routine to do the flattening; it wants a PlannerInfo root node, which * fortunately can be mostly dummy. */ if (hasJoinRTEs) { root = makeNode(PlannerInfo); root->parse = qry; root->planner_cxt = CurrentMemoryContext; root->hasJoinRTEs = true; groupClauses = (List *) flatten_join_alias_vars(root, (Node *) groupClauses); } else root = NULL; /* keep compiler quiet */ /* * Detect whether any of the grouping expressions aren't simple Vars; if * they're all Vars then we don't have to work so hard in the recursive * scans. (Note we have to flatten aliases before this.) */ have_non_var_grouping = false; foreach(l, groupClauses) { if (!IsA((Node *) lfirst(l), Var)) { have_non_var_grouping = true; break; } } /* * Check the targetlist and HAVING clause for ungrouped variables. * * Note: because we check resjunk tlist elements as well as regular ones, * this will also find ungrouped variables that came from ORDER BY and * WINDOW clauses. For that matter, it's also going to examine the * grouping expressions themselves --- but they'll all pass the test ... */ clause = (Node *) qry->targetList; if (hasJoinRTEs) clause = flatten_join_alias_vars(root, clause); check_ungrouped_columns(clause, pstate, qry, groupClauses, have_non_var_grouping, &func_grouped_rels); clause = (Node *) qry->havingQual; if (hasJoinRTEs) clause = flatten_join_alias_vars(root, clause); check_ungrouped_columns(clause, pstate, qry, groupClauses, have_non_var_grouping, &func_grouped_rels); /* * Per spec, aggregates can't appear in a recursive term. */ if (pstate->p_hasAggs && hasSelfRefRTEs) ereport(ERROR, (errcode(ERRCODE_INVALID_RECURSION), errmsg("aggregate functions are not allowed in a recursive query's recursive term"), parser_errposition(pstate, locate_agg_of_level((Node *) qry, 0)))); } /* * check_ungrouped_columns - * Scan the given expression tree for ungrouped variables (variables * that are not listed in the groupClauses list and are not within * the arguments of aggregate functions). Emit a suitable error message * if any are found. * * NOTE: we assume that the given clause has been transformed suitably for * parser output. This means we can use expression_tree_walker. * * NOTE: we recognize grouping expressions in the main query, but only * grouping Vars in subqueries. For example, this will be rejected, * although it could be allowed: * SELECT * (SELECT x FROM bar where y = (foo.a + foo.b)) * FROM foo * GROUP BY a + b; * The difficulty is the need to account for different sublevels_up. * This appears to require a whole custom version of equal(), which is * way more pain than the feature seems worth. */ static void check_ungrouped_columns(Node *node, ParseState *pstate, Query *qry, List *groupClauses, bool have_non_var_grouping, List **func_grouped_rels) { check_ungrouped_columns_context context; context.pstate = pstate; context.qry = qry; context.groupClauses = groupClauses; context.have_non_var_grouping = have_non_var_grouping; context.func_grouped_rels = func_grouped_rels; context.sublevels_up = 0; context.in_agg_direct_args = false; check_ungrouped_columns_walker(node, &context); } static bool check_ungrouped_columns_walker(Node *node, check_ungrouped_columns_context *context) { ListCell *gl; if (node == NULL) return false; if (IsA(node, Const) || IsA(node, Param)) return false; /* constants are always acceptable */ if (IsA(node, Aggref)) { Aggref *agg = (Aggref *) node; if ((int) agg->agglevelsup == context->sublevels_up) { /* * If we find an aggregate call of the original level, do not * recurse into its normal arguments, ORDER BY arguments, or * filter; ungrouped vars there are not an error. But we should * check direct arguments as though they weren't in an aggregate. * We set a special flag in the context to help produce a useful * error message for ungrouped vars in direct arguments. */ bool result; Assert(!context->in_agg_direct_args); context->in_agg_direct_args = true; result = check_ungrouped_columns_walker((Node *) agg->aggdirectargs, context); context->in_agg_direct_args = false; return result; } /* * We can skip recursing into aggregates of higher levels altogether, * since they could not possibly contain Vars of concern to us (see * transformAggregateCall). We do need to look at aggregates of lower * levels, however. */ if ((int) agg->agglevelsup > context->sublevels_up) return false; } /* * If we have any GROUP BY items that are not simple Vars, check to see if * subexpression as a whole matches any GROUP BY item. We need to do this * at every recursion level so that we recognize GROUPed-BY expressions * before reaching variables within them. But this only works at the outer * query level, as noted above. */ if (context->have_non_var_grouping && context->sublevels_up == 0) { foreach(gl, context->groupClauses) { if (equal(node, lfirst(gl))) return false; /* acceptable, do not descend more */ } } /* * If we have an ungrouped Var of the original query level, we have a * failure. Vars below the original query level are not a problem, and * neither are Vars from above it. (If such Vars are ungrouped as far as * their own query level is concerned, that's someone else's problem...) */ if (IsA(node, Var)) { Var *var = (Var *) node; RangeTblEntry *rte; char *attname; if (var->varlevelsup != context->sublevels_up) return false; /* it's not local to my query, ignore */ /* * Check for a match, if we didn't do it above. */ if (!context->have_non_var_grouping || context->sublevels_up != 0) { foreach(gl, context->groupClauses) { Var *gvar = (Var *) lfirst(gl); if (IsA(gvar, Var) && gvar->varno == var->varno && gvar->varattno == var->varattno && gvar->varlevelsup == 0) return false; /* acceptable, we're okay */ } } /* * Check whether the Var is known functionally dependent on the GROUP * BY columns. If so, we can allow the Var to be used, because the * grouping is really a no-op for this table. However, this deduction * depends on one or more constraints of the table, so we have to add * those constraints to the query's constraintDeps list, because it's * not semantically valid anymore if the constraint(s) get dropped. * (Therefore, this check must be the last-ditch effort before raising * error: we don't want to add dependencies unnecessarily.) * * Because this is a pretty expensive check, and will have the same * outcome for all columns of a table, we remember which RTEs we've * already proven functional dependency for in the func_grouped_rels * list. This test also prevents us from adding duplicate entries to * the constraintDeps list. */ if (list_member_int(*context->func_grouped_rels, var->varno)) return false; /* previously proven acceptable */ Assert(var->varno > 0 && (int) var->varno <= list_length(context->pstate->p_rtable)); rte = rt_fetch(var->varno, context->pstate->p_rtable); if (rte->rtekind == RTE_RELATION) { if (check_functional_grouping(rte->relid, var->varno, 0, context->groupClauses, &context->qry->constraintDeps)) { *context->func_grouped_rels = lappend_int(*context->func_grouped_rels, var->varno); return false; /* acceptable */ } } /* Found an ungrouped local variable; generate error message */ attname = get_rte_attribute_name(rte, var->varattno); if (context->sublevels_up == 0) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("column \"%s.%s\" must appear in the GROUP BY clause or be used in an aggregate function", rte->eref->aliasname, attname), context->in_agg_direct_args ? errdetail("Direct arguments of an ordered-set aggregate must use only grouped columns.") : 0, parser_errposition(context->pstate, var->location))); else ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("subquery uses ungrouped column \"%s.%s\" from outer query", rte->eref->aliasname, attname), parser_errposition(context->pstate, var->location))); } if (IsA(node, Query)) { /* Recurse into subselects */ bool result; context->sublevels_up++; result = query_tree_walker((Query *) node, check_ungrouped_columns_walker, (void *) context, 0); context->sublevels_up--; return result; } return expression_tree_walker(node, check_ungrouped_columns_walker, (void *) context); } /* * get_aggregate_argtypes * Identify the specific datatypes passed to an aggregate call. * * Given an Aggref, extract the actual datatypes of the input arguments. * The input datatypes are reported in a way that matches up with the * aggregate's declaration, ie, any ORDER BY columns attached to a plain * aggregate are ignored, but we report both direct and aggregated args of * an ordered-set aggregate. * * Datatypes are returned into inputTypes[], which must reference an array * of length FUNC_MAX_ARGS. * * The function result is the number of actual arguments. */ int get_aggregate_argtypes(Aggref *aggref, Oid *inputTypes) { int numArguments = 0; ListCell *lc; /* Any direct arguments of an ordered-set aggregate come first */ foreach(lc, aggref->aggdirectargs) { Node *expr = (Node *) lfirst(lc); inputTypes[numArguments] = exprType(expr); numArguments++; } /* Now get the regular (aggregated) arguments */ foreach(lc, aggref->args) { TargetEntry *tle = (TargetEntry *) lfirst(lc); /* Ignore ordering columns of a plain aggregate */ if (tle->resjunk) continue; inputTypes[numArguments] = exprType((Node *) tle->expr); numArguments++; } return numArguments; } /* * resolve_aggregate_transtype * Identify the transition state value's datatype for an aggregate call. * * This function resolves a polymorphic aggregate's state datatype. * It must be passed the aggtranstype from the aggregate's catalog entry, * as well as the actual argument types extracted by get_aggregate_argtypes. * (We could fetch these values internally, but for all existing callers that * would just duplicate work the caller has to do too, so we pass them in.) */ Oid resolve_aggregate_transtype(Oid aggfuncid, Oid aggtranstype, Oid *inputTypes, int numArguments) { /* resolve actual type of transition state, if polymorphic */ if (IsPolymorphicType(aggtranstype)) { /* have to fetch the agg's declared input types... */ Oid *declaredArgTypes; int agg_nargs; (void) get_func_signature(aggfuncid, &declaredArgTypes, &agg_nargs); /* * VARIADIC ANY aggs could have more actual than declared args, but * such extra args can't affect polymorphic type resolution. */ Assert(agg_nargs <= numArguments); aggtranstype = enforce_generic_type_consistency(inputTypes, declaredArgTypes, agg_nargs, aggtranstype, false); pfree(declaredArgTypes); } return aggtranstype; } /* * Create expression trees for the transition and final functions * of an aggregate. These are needed so that polymorphic functions * can be used within an aggregate --- without the expression trees, * such functions would not know the datatypes they are supposed to use. * (The trees will never actually be executed, however, so we can skimp * a bit on correctness.) * * agg_input_types, agg_state_type, agg_result_type identify the input, * transition, and result types of the aggregate. These should all be * resolved to actual types (ie, none should ever be ANYELEMENT etc). * agg_input_collation is the aggregate function's input collation. * * For an ordered-set aggregate, remember that agg_input_types describes * the direct arguments followed by the aggregated arguments. * * transfn_oid, invtransfn_oid and finalfn_oid identify the funcs to be * called; the latter two may be InvalidOid. * * Pointers to the constructed trees are returned into *transfnexpr, * *invtransfnexpr and *finalfnexpr. If there is no invtransfn or finalfn, * the respective pointers are set to NULL. Since use of the invtransfn is * optional, NULL may be passed for invtransfnexpr. */ void build_aggregate_fnexprs(Oid *agg_input_types, int agg_num_inputs, int agg_num_direct_inputs, int num_finalfn_inputs, bool agg_variadic, Oid agg_state_type, Oid agg_result_type, Oid agg_input_collation, Oid transfn_oid, Oid invtransfn_oid, Oid finalfn_oid, Expr **transfnexpr, Expr **invtransfnexpr, Expr **finalfnexpr) { Param *argp; List *args; FuncExpr *fexpr; int i; /* * Build arg list to use in the transfn FuncExpr node. We really only care * that transfn can discover the actual argument types at runtime using * get_fn_expr_argtype(), so it's okay to use Param nodes that don't * correspond to any real Param. */ argp = makeNode(Param); argp->paramkind = PARAM_EXEC; argp->paramid = -1; argp->paramtype = agg_state_type; argp->paramtypmod = -1; argp->paramcollid = agg_input_collation; argp->location = -1; args = list_make1(argp); for (i = agg_num_direct_inputs; i < agg_num_inputs; i++) { argp = makeNode(Param); argp->paramkind = PARAM_EXEC; argp->paramid = -1; argp->paramtype = agg_input_types[i]; argp->paramtypmod = -1; argp->paramcollid = agg_input_collation; argp->location = -1; args = lappend(args, argp); } fexpr = makeFuncExpr(transfn_oid, agg_state_type, args, InvalidOid, agg_input_collation, COERCE_EXPLICIT_CALL); fexpr->funcvariadic = agg_variadic; *transfnexpr = (Expr *) fexpr; /* * Build invtransfn expression if requested, with same args as transfn */ if (invtransfnexpr != NULL) { if (OidIsValid(invtransfn_oid)) { fexpr = makeFuncExpr(invtransfn_oid, agg_state_type, args, InvalidOid, agg_input_collation, COERCE_EXPLICIT_CALL); fexpr->funcvariadic = agg_variadic; *invtransfnexpr = (Expr *) fexpr; } else *invtransfnexpr = NULL; } /* see if we have a final function */ if (!OidIsValid(finalfn_oid)) { *finalfnexpr = NULL; return; } /* * Build expr tree for final function */ argp = makeNode(Param); argp->paramkind = PARAM_EXEC; argp->paramid = -1; argp->paramtype = agg_state_type; argp->paramtypmod = -1; argp->paramcollid = agg_input_collation; argp->location = -1; args = list_make1(argp); /* finalfn may take additional args, which match agg's input types */ for (i = 0; i < num_finalfn_inputs - 1; i++) { argp = makeNode(Param); argp->paramkind = PARAM_EXEC; argp->paramid = -1; argp->paramtype = agg_input_types[i]; argp->paramtypmod = -1; argp->paramcollid = agg_input_collation; argp->location = -1; args = lappend(args, argp); } *finalfnexpr = (Expr *) makeFuncExpr(finalfn_oid, agg_result_type, args, InvalidOid, agg_input_collation, COERCE_EXPLICIT_CALL); /* finalfn is currently never treated as variadic */ }