From: "n.pettik" <korablev@tarantool.org> To: tarantool-patches@freelists.org Cc: Kirill Shcherbatov <kshcherbatov@tarantool.org> Subject: [tarantool-patches] Re: [PATCH v1 1/1] sql: support HAVING without GROUP BY clause Date: Tue, 11 Sep 2018 00:43:26 +0300 [thread overview] Message-ID: <00C60996-AB0B-4157-AF8D-DCD9B1F63D8D@tarantool.org> (raw) In-Reply-To: <077750b5-7433-6122-5df9-caa6ff462e70@tarantool.org> Still, other DBs (as usual I checked - Postgres, Oracle and DB2) process this query as well: select 1 from t1 having min(a) > 0; In other words, not only aggregate can appear in SELECT args, but also constant literals. Semantically, it seems to be correct. Moreover, quieres like select date() from t1 having min(a) > 0; are valid too. What I mean is SELECT arguments must return single value for all rows in table (i.e. be single-group). From the first sight, this problem is likely to be minor, but I guess we should implement correct behaviour as far as we are dealing with this issue right now. > diff --git a/src/box/sql/resolve.c b/src/box/sql/resolve.c > index 280ecd9..c38374d 100644 > --- a/src/box/sql/resolve.c > +++ b/src/box/sql/resolve.c > @@ -600,6 +600,8 @@ resolveExprStep(Walker * pWalker, Expr * pExpr) > /* A lone identifier is the name of a column. > */ > case TK_ID:{ > + if ((pNC->ncFlags & NC_AllowAgg) != 0) > + pNC->ncFlags |= NC_HasUnaggregatedId; > return lookupName(pParse, 0, pExpr->u.zToken, pNC, > pExpr); > } > @@ -1283,13 +1285,19 @@ resolveSelectStep(Walker * pWalker, Select * p) > /* Set up the local name-context to pass to sqlite3ResolveExprNames() to > * resolve the result-set expression list. > */ > + bool all_select_agg = true; Nit: use ‘is_’ or ‘if_’ prefix for predicate variable. > sNC.ncFlags = NC_AllowAgg; > sNC.pSrcList = p->pSrc; > sNC.pNext = pOuterNC; > - > /* Resolve names in the result set. */ > - if (sqlite3ResolveExprListNames(sNC, p->pEList)) > - return WRC_Abort; Leave here explanation comment pls. Without any notion it is quite hard to understand that this snippet helps to check HAVING without GROUP BY queries. > + for (i = 0; i < p->pEList->nExpr; i++) { > + u16 has_agg_flag = sNC.ncFlags & NC_HasAgg; > + sNC.ncFlags &= ~NC_HasAgg; > + if (sqlite3ResolveExprNames(&sNC, p->pEList->a[i].pExpr)) > + return WRC_Abort; > + all_select_agg &= (sNC.ncFlags & NC_HasAgg) != 0; > + sNC.ncFlags |= has_agg_flag; > + }
next prev parent reply other threads:[~2018-09-10 21:43 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-08-28 16:39 [tarantool-patches] " Kirill Shcherbatov 2018-08-29 11:52 ` [tarantool-patches] " n.pettik 2018-08-29 13:29 ` Kirill Shcherbatov 2018-09-03 11:24 ` n.pettik 2018-09-03 13:23 ` n.pettik 2018-09-10 7:51 ` Kirill Shcherbatov 2018-09-10 21:43 ` n.pettik [this message] 2018-09-20 12:43 ` Kirill Shcherbatov 2018-10-01 16:37 ` n.pettik
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