Yes, thanks.
The 'left join on' or 'inner join on ' removes the chance of an
erroneous key linkage.
Also makes sense to pay close attention as to which table is left and
right.
Ken
On 01/09/2017 06:46 AM, Dominique Devienne wrote:
On Sun, Jan 8, 2017 at 12:46 PM, Keith Medcalf <kmedc...@dessus.com> wrote:
... join ... using (column) has nothing whatever to do with foreign keys.
"FROM a JOIN b USING (c) is "syntactic sugar" ([...]) for the expression
"FROM a, b WHERE a.c = b.c"
Or "FROM a JOIN b ON a.c = b.c".
Or "FROM a INNER JOIN b ON a.c = b.c".
Syntax does matter (to some?) for readability and comprehension of a query
IMHO.
I prefer to keep my WHERE clauses for single-table "filtering",
and rely on JOIN-ON for how two tables "connect" during a join.
(which columns to "thread the needle through" to form/constitute
a "multi-table row" is my personal mental image of a join).
My $0.02. --DD
PS: I myself consider "FROM a, b WHERE a.c = b.c" to be the "legacy"
syntax, best avoided :)
_______________________________________________
sqlite-users mailing list
sqlite-users@mailinglists.sqlite.org
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
_______________________________________________
sqlite-users mailing list
sqlite-users@mailinglists.sqlite.org
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
