Re: [HACKERS] precision and scale functions for numeric
On Sun, Apr 29, 2012 at 1:51 PM, Peter Eisentraut pete...@gmx.net wrote: I didn't find a good way to find out how many digits a numeric value has or things like whether a numeric value is an integer. (I had to go through bc(1) for the latter.) Functions like precision() and scale() would have been quite handy. Are there other ways to do this, or would this make a good addition? I think you could test for integer-ness by testing whether val % 0 = 0. You could in general test of digits after the decimal point by casting the value to text and using POSITION() to find the decimal point. If POSITION() returns zero then zero; else subtract the result from the string length. Similarly, it's pretty easy to regexp away the non-digits and measure the length of the resulting string. I don't have a good feeling for whether these operations are common enough to justify adding a few more functions. They haven't yet come up for me personally. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] precision and scale functions for numeric
-Original Message- From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers- ow...@postgresql.org] On Behalf Of Robert Haas Sent: Monday, April 30, 2012 2:20 PM To: Peter Eisentraut Cc: pgsql-hackers Subject: Re: [HACKERS] precision and scale functions for numeric I think you could test for integer-ness by testing whether val % 0 = 0. Either I am missing something here or you are. Since Modulus is a division function anything % 0 results in a division-by-zero ERROR - division has to occur before a remainder can be obtained. Maybe val % 2 NOT IN (0,1) ... David J. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] precision and scale functions for numeric
On Mon, Apr 30, 2012 at 3:33 PM, David Johnston pol...@yahoo.com wrote: -Original Message- From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers- ow...@postgresql.org] On Behalf Of Robert Haas Sent: Monday, April 30, 2012 2:20 PM To: Peter Eisentraut Cc: pgsql-hackers Subject: Re: [HACKERS] precision and scale functions for numeric I think you could test for integer-ness by testing whether val % 0 = 0. Either I am missing something here or you are. Since Modulus is a division function anything % 0 results in a division-by-zero ERROR - division has to occur before a remainder can be obtained. Maybe val % 2 NOT IN (0,1) ... Oops. I meant (val % 1) = 0, not (val % 0) = 0. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] precision and scale functions for numeric
David Johnston pol...@yahoo.com wrote: I think you could test for integer-ness by testing whether val % 0 = 0. Modulus is a division function anything % 0 results in a division-by-zero It seems pretty clear that he meant % 1. test=# select '1.01'::numeric % 1; ?column? -- 0.01 (1 row) -Kevin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
