How to calculate bits?

[arethaking]

Hi All, hic

Date(Floor(Timestamp)) as Date,
   Time(Floor(Frac(Timestamp),1/24/60)) as Time,
These expressions will give you at most 24*60=1440 distinct time values (11 bits) and typically 365 distinct dates (9 bits)

How to calculate bits? How 11 bits and 9 bits?

Thanks in advance.

[tresesco]

Have a look at :

rwunderlich‌'s blog: Memory sizes for data types | Qlikview Cookbook

marcus_sommer‌'s illustrative document: ByteSizes from Values in QlikView

[hic]

You use 2 to the power of N to calculate how many values N bits can hold:

Number of bits	Number of values
1	2
2	4
3	8
8	256
9	512
10	1024
11	2048

Then it is easy to see that 366 days fit in 9 bits, and 1440 minutes fit in 11 bits.

HIC