 MySQL Float Type help! Float[(m,d)] 
AthlonInside
msg:1259307  5:44 pm on Aug 17, 2005 (gmt 0)  FLOAT[(M,D)] [UNSIGNED] [ZEROFILL] A small (singleprecision) floatingpoint number. Allowable values are 3.402823466E+38 to 1.175494351E38, 0, and 1.175494351E38 to 3.402823466E+38. If UNSIGNED is specified, negative values are disallowed. M is the display width and D is the number of significant digits. FLOAT without arguments or FLOAT(p) (where p is in the range from 0 to 24) stands for a singleprecision floatingpoint number. What is display width and what is significant digits?! Can anyone give me some examples. thank you.

mcibor
msg:1259308  8:34 pm on Aug 17, 2005 (gmt 0)  I'm not sure what is display width, but D is the number of significant digits. Significant digit is the first number after zeros, so 0,0000324 it's 3 1000,0002 it's 1 0,90001 it's 9 In above example the number of significant digits was: 3; 8; 5 correspondedly. The more significant digits the better precision and more numbers you can write. I think that M  the display width is how many digits will be returned on the query: M = 3; then we get: 3.24E5; 1.00E3; 9.00E1 I'm not sure for that one however  you'll have to check on your own or somebody else will answer. Best regards Michal Cibor

AthlonInside
msg:1259309  4:43 pm on Aug 18, 2005 (gmt 0)  Thanks for your reply. getting better understanding. In the above case, it is a float number. So for 3.145 how would you calculate the significant digit?

mcibor
msg:1259310  5:35 pm on Aug 18, 2005 (gmt 0)  for 3.142 it's 4 significant digits for 3.1416 it's 5 for 3.141592 it's 7 but as well for 0.00000003141592 it's 7 significant digits (zeros at the beginning don't count) However 3.000000 it's 7 and 3000000 it's as well 7 So beginning zeros don't count, but trailing zeros do count! In the 5th example you see that the value is 3 up to the 6th place If you would write it as 3 it could mean that it is something between 2.5 and 3.499999... whereas 3.000000 is between 2.9999995 and 3.0000004999... Best regards Michal Cibor PS. Writing this I recall my Measures teacher who said  don't measure your best  measure good! :)


