Tom Lane wrote: > Moving to the left requires an explicit cast (or at least an assignment > to a column). I know this looks strange to someone who knows that our > numeric type beats float4/float8 on both range and precision, but it's > effectively mandated by the SQL spec. Any combination of "exact" and > "inexact" numeric types is supposed to yield an "inexact" result per > spec, thus numeric + float8 yields float8 not numeric. Another reason > for doing it this way is that a numeric literal like "123.456" can be > initially typed as numeric, and later implicitly promoted to float4 or > float8 if context demands it. Doing that the other way 'round would > introduce problems with precision loss. We had speculated about > introducing an "unknown_numeric" pseudo-type to avoid that problem, but > the above hierarchy eliminates the need for "unknown_numeric". We can > initially type a literal as the smallest thing it will fit in, and then > do implicit promotion as needed. (7.3 is not all the way there on that > plan, but 7.4 will be.)
Do we know that defaulting floating constants will not be a performance hit? -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
