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A small (single-precision) floating-point number. Allowable values are -3.402823466E+38 to -1.175494351E-38, 0, and 1.175494351E-38 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 single-precision floating-point number.
What is display width and what is significant digits?!
Can anyone give me some examples. thank you.
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: 3.24E-5; 1.00E3; 9.00E-1
I'm not sure for that one however - you'll have to check on your own or somebody else will answer.
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...
PS. Writing this I recall my Measures teacher who said - don't measure your best - measure good! :)