This behaviour is due to data type precedence.
(@v1 / @v2 ) * @v3 will return smallmoney
((@v1 * 1.0) / @v2 ) * @v3 will return numeric
This can be demonstrated like this:
DECLARE @v1 SMALLMONEY = 1400.05,
@v2 SMALLMONEY = 4232.33;
SELECT @v1 / @v2 AS Val INTO TestTable1
SELECT @v1 / @v2 * 1.0 AS Val INTO TestTable2
EXEC sp_help TestTable1
EXEC sp_help TestTable2
DROP TABLE TestTable1
DROP TABLE TestTable2
And you will see the following:
TestTable1
Name - Val
Type - smallmoney
Length - 4
Precision - 10
Scale - 4
TestTable 2
Name - Val
Type - numeric
Length - 9
Precision - 13
Scale - 5
