Hi Frank: On Tue, Mar 15, 2016 at 6:57 AM, Frank Millman <frank@xxxxxxxxxxxx> wrote: > 2. As pointed out, there are two forms of the power function. > > test=> select pg_typeof(power(10, 2)); > pg_typeof > ------------------ > double precision > > test=> select pg_typeof(power(10., 2)); > pg_typeof > ---------- > numeric > > I found that adding a decimal point after the 10 is the easiest way to force > it to return a numeric. > > Putting this together, my solution is - > > test=> select floor(4.725 * power(10., 2) + 0.5); > floor > ------- > 473 > Can anyone see any problems with this? I see a problem in it relying in interpretation of constants. From my experience I would recommend explicit casts, it's just a second longer to type but much clearer. The problems start with 10 being interpreted as integer, all the other ones as numeric: s=> select pg_typeof(10.), pg_typeof(10), pg_typeof(10.E0), pg_typeof(10E0); pg_typeof | pg_typeof | pg_typeof | pg_typeof -----------+-----------+-----------+----------- numeric | integer | numeric | numeric (1 row) This may byte you any day, so I wuld recommend doing s=> select v, pg_typeof(v) from (select floor(4.725 * power(cast(10. as numeric), 2) + 0.5)) as aux(v); v | pg_typeof -----+----------- 473 | numeric (1 row) s=> select v, pg_typeof(v) from (select floor(4.725 * power(cast(10 as numeric), 2) + 0.5)) as aux(v); v | pg_typeof -----+----------- 473 | numeric (1 row) which makes your intention clear. Francisco Olarte. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
