Thanks for the replie!!! :), I'll make some research. On 20 March 2012 18:38, Pete <p...@mollysrevenge.com> wrote:
> Hi Ken, > Good catch on the multiple FROM clauses, not sure what that's all about. > Probably just needs to qualify the columns in the condition with the table > name. > > The SELECT statement has a lot of problems in general. There's no JOIN > statement to link table1 and table2 together, for example. That might work > as long as the column(s) to be used to join the tables together have the > same name in both tables but in general, it's much better to explicitly > define the linkage with a JOIN statement - for clarity reasons if no other. > > Just one comment on the need to qualify columns with table names. I > definitely agree it's good practice to do that for clarity but as long as a > column name is unique among all tables, SQL will figure out which table an > unqualified column name belongs to. > > Pete > > On Tue, Mar 20, 2012 at 8:46 AM, Ken Ray <k...@sonsothunder.com> wrote: > > > > > On Mar 20, 2012, at 4:20 AM, Marek Reichenbach wrote: > > > > > Thanks for the replies. > > > I've made it workin, but I wanna add something else: > > > > > > So the question in SQL is: > > > > > > Maybe there is a way to hide columns it the result, like: > > > SELECT car_nr, model, travel_days FROM table1,table2 WHERE number <> > 414 > > > AND (car_nr > truck_nr) from transport; > > > and show only result of the colums travel_days, but ONLY on* > > > **separate* columns > > > and HIDE OTHER COLUMNS. > > > > You only include the columns you want back in the SELECT part of the > query: > > > > SELECT travel_days FROM … > > > > Also, although I know you provided a dummy query, be aware that there are > > two inherent problems with the one you provided: > > > > 1) If you have multiple tables in the FROM clause, you need to identify > > the table attached to the column in the SELECT clause (although some SQL > > engines might just assume you meant the first table, it's good form to > > identify the table), either by full name: > > > > SELECT table1.travel_days FROM table1,table2 WHERE… > > > > or by alias: > > > > SELECT t1.travel_days FROM table1 t1,table2 t2 WHERE… > > > > 2) I'm not sure what "from transport" means since you already have a FROM > > clause in your example query > > > > The bottom line is that you don't have to include columns in the SELECT > > portion of the query that you don't want back, so long as you identify > them > > properly and they actually exist in the table you're referencing. > > > > Just be aware that LiveCode's text parsing is second to none, so there > are > > usually times where it may actually be easier and more efficient to let > SQL > > handle getting the data, but let LiveCode handle parsing the data after > it > > arrives. As I mentioned in an earlier post, you *can* use SQL to change > > your numbers to "+" symbols, but it's ugly - Mark's method to > post-process > > it in LC with a single statement if far better (IMHO). > > > > Ken Ray > > Sons of Thunder Software, Inc. > > Email: k...@sonsothunder.com > > Web Site: http://www.sonsothunder.com/ > > > > _______________________________________________ > > use-livecode mailing list > > use-livecode@lists.runrev.com > > Please visit this url to subscribe, unsubscribe and manage your > > subscription preferences: > > http://lists.runrev.com/mailman/listinfo/use-livecode > > > > > > > -- > Pete > Molly's Revenge <http://www.mollysrevenge.com> > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
