XML FeedsThat may seem a little harsh, and it's not always true. However, most of the time, the float data type should be avoided. Unfortunately, the float (and real) data types are approximate data types that can lead to significant rounding errors.
How to detect this problem:
tsql
- Select Table_Name + '.' + Column_Name As Name, 'Table' As ObjectType
- From Information_Schema.Columns
- Where Data_Type in ('Float', 'Real')
- UNION ALL
- SELECT Name, Types.Description
- FROM (
- SELECT S.Name, S.XType, C.TEXT
- FROM sysobjects S
- INNER Join syscomments C
- ON S.id = C.id
- And S.xtype in ('P', 'v', 'TF', 'FN')
- WHERE OBJECTPROPERTY(S.ID, N'IsMSShipped') = 0
- UNION All
- SELECT OBJECT_NAME(A.id), s.XType, LeftText + RightText
- FROM sysobjects s
- INNER Join (
- SELECT Id, RIGHT(TEXT, 10) AS LeftText, ColId
- FROM syscomments
- ) AS A
- ON S.id = A.id
- And OBJECTPROPERTY(S.ID, N'IsMSShipped') = 0
- And S.xtype in ('P', 'v', 'TF', 'FN')
- INNER Join (
- SELECT Id, LEFT(TEXT, 10) AS RightText, ColId
- FROM syscomments
- ) AS B
- ON A.id = B.id
- and A.ColId = B.ColId - 1
- ) AS A
- Inner join (
- Select 'FN' As XType, 'Function' As Description
- Union All
- Select 'P' As XType, 'Procedure' As Description
- Union All
- Select 'V' As XType, 'View' As Description
- Union All
- Select 'TF' As XType, 'Table Values Function' As Description
- ) As Types
- On A.XType = Types.XType
- WHERE TEXT Like '%float[^(]%'
- ORDER BY Name
How to correct it: Examine the data you are using and identify the precision and scale required. Change the data type (or code) to use a decimal with the precision and scale you require.
Level of severity: Moderate
Level of difficulty: Easy
I've been saying this for years and having it mostly fall on deaf ears. Amazing how programmers don't understand about rounding errors! 
Hopefully the code I provide above will help you determine where the float data type is used so that it is easier to fix this potential problem. 
Unfortunately the numeric types can have pretty serious rounding issues as well, depending on how you have them configured. To get around this I sometimes use FLOAT as an intermediary when I need to deal with very small values and -some- value is better than rounding to zero.
Interestingly this is posted in Database Weekly
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