How can I convert Float numbers which are represented as 'E-05' to full precision

Question

I have over 6,000 records which all have 'E-05' in the field.
It should actually be full precision, such as:  0.000046793055472781
How can I convert all of these?  There are around 600,000 records in the whole table, so I only want to convert the 'E-05' records.  For some reason these are incorrect, but all the others are totally fine.
Knowledge is the only thing that I can give you, and still retain, and we are both better off for it.

Answer 1

If they are float values, they have the full precision you can get with a float value.
Keep in mind that what you see in management studio is a textual representation of the value. It is not the value itself. A float value is stored as 53 bits of mantissa and an 11-bit exponent which is a power of 2.
To view the value without the exponent, you can cast to decimal, although this will give you a slightly different value. You can also use the str function:
DECLARE @f float
SELECT @f = 0.000046793055472781
SELECT str(@f, 20, 18)
However, formatting of the value is best done in the presentation layer. You should not change the data you have in the table. But if the source is actually exact decimal values, maybe you should use a decimal data type instead.
Erland Sommarskog, SQL Server MVP, [email protected]