SQL 从整数转换为十进制

Question

I have two columns in a table that are populated with integer values. For each record, I want to divide the values of those two columns and format the output so that the decimal point is moved to places to the right.

For example, if I have values of the two columns for one record as 4 and 1 and I want to divide 1 by 4 (so 1/4) then I want the output to be 25.00.

Here is the last thing I tried a bit ago:

CAST(Total AS Decimal(2))/CAST(TotalAnswers AS Decimal(2)) AS 'Percent' 

I have not been able to find a syntactical explanation of the CAST function to see what the parameter passed in for decimal represents. When I change it, it does sometimes change the number of places to the right of the decimal but the results are not always what I expect so I would like to get a little help on this.

Answer 1

Write it like this:

SELECT CAST(CAST(Total As float) / TotalAnswers * 100 As decimal(8, 2))

Answer 2

DECIMAL(2) is a decimal of 2 digits before and no digits after the decimal point. That doesn't allow you to have digits after the decimal point!

The DECIMAL(p,s) specification defines the number of total digits ( p ) and the number of digits after the decimal point ( s ) (where s cannot be larger than p and is 0 if ommitted).

You need to use something like DECIMAL(4,2) ( 4 digit total - 2 of which after the decimal point; so therefore: also 2 before the decimal point ) or something like that - some digits before and some after the decimal point - then you'll see your desired result!

For details on the DECIMAL type and its syntax, consult the MSDN Books Online topic on decimal and numeric

Answer 3

There are actual a couple of parameters..

(p, s)

where

• p represents the "precision" - the total number of digits before and after the decimal point.
• s represents the "scale" - the number of digits after the decimal point.

By only giving 1 parameter, you are giving the precision only.

See MDSN .

Answer 4

from book-online for decimal data type: Numeric data types that have fixed precision and scale.

decimal[ (p[, s] )] and numeric[ (p[, s] )] Fixed precision and scale numbers. When maximum precision is used, valid values are from - 10^38 +1 through 10^38 - 1. The SQL-92 synonyms for decimal are dec and dec(p, s). numeric is functionally equivalent to decimal.

p (precision) The maximum total number of decimal digits that can be stored, both to the left and to the right of the decimal point. The precision must be a value from 1 through the maximum precision of 38. The default precision is 18.

s (scale) The maximum number of decimal digits that can be stored to the right of the decimal point. Scale must be a value from 0 through p. Scale can be specified only if precision is specified. The default scale is 0; therefore, 0 <= s <= p. Maximum storage sizes vary, based on the precision.