Re: MonetDB: default - Support LIMIT in scalar expressions

As Martin vD suggested in his comment in bug 6333, FIRST() and LAST() have no clearly defined (intuitive) semantics in set-oriented SQL --- even LIMIT n without order by does not, other some returning "any" n tuples, possibly different ones with each query invocation (i.e., not even "guaranteed" to be deterministic). Thus, maybe we could consider "ANY()" instead of "FIRST()" & "LAST()"? Stefan ----- On Jul 12, 2017, at 11:31 AM, Lefteris lsidir@gmail.com wrote:

maybe we could also support FIRST() and LAST()

https://www.monetdb.org/bugzilla/show_bug.cgi?id=6333

On Wed, Jul 12, 2017 at 11:22 AM, Martin Kersten wrote:

...

Changeset: 718758b70621 for MonetDB URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=718758b70621 Modified Files: sql/server/sql_parser.y Branch: default Log Message:

Support LIMIT in scalar expressions Picking a single element from a table is now supported using LIMIT (and SAMPLE) in SET and UPDATE subqueries

set v =(select * from tbl limit 1);

diffs (21 lines):

diff --git a/sql/server/sql_parser.y b/sql/server/sql_parser.y --- a/sql/server/sql_parser.y +++ b/sql/server/sql_parser.y @@ -772,7 +772,7 @@ set_statement: append_string(l, $2 ); append_symbol(l, $4 ); $$ = _symbol_create_list( SQL_SET, l); } - | set column_commalist_parens '=' subquery + | set column_commalist_parens '=' subquery_with_orderby { dlist *l = L(); append_list(l, $2); append_symbol(l, $4); @@ -2919,7 +2919,7 @@ assignment: append_symbol(l, $3 ); append_string(l, $1); $$ = _symbol_create_list( SQL_ASSIGN, l); } - | column_commalist_parens '=' subquery + | column_commalist_parens '=' subquery_with_orderby { dlist *l = L(); append_symbol(l, $3); append_list(l, $1); _______________________________________________ checkin-list mailing list checkin-list@monetdb.org https://www.monetdb.org/mailman/listinfo/checkin-list

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