The MULTIPLY_ALT scalar function returns the product of the two arguments as a decimal value. It is provided as an alternative to the multiplication operator, especially when the sum of the precisions of the arguments exceeds 63.
The result of the function is a DECIMAL. The precision and scale of the result are determined as follows, using the symbols p and s to denote the precision and scale of the first argument, and the symbols p' and s' to denote the precision and scale of the second argument.
For information on the values of p, s, ms, and mp, see Decimal arithmetic in SQL.
The result can be null if at least one argument can be null; the result is the null value if one of the arguments is null.
The MULTIPLY_ALT function is a better choice than the multiplication operator when performing decimal arithmetic where a scale of at least 3 is desired and the sum of the precisions exceeds 63. In these cases, the internal computation is performed so that overflows are avoided and then assigned to the result type value using truncation for any loss of scale in the final result. Note that the possibility of overflow of the final result is still possible when the scale is 3.
The following table compares the result types using MULTIPLY_ALT and the multiplication operator when the maximum precision is 31 and the maximum scale is 31:
Type of Argument 1 | Type of Argument 2 | Result using MULTIPLY_ALT | Result using multiplication operator |
---|---|---|---|
DECIMAL(31,3) | DECIMAL(15,8) | DECIMAL(31,3) | DECIMAL(31,11) |
DECIMAL(26,23) | DECIMAL(10,1) | DECIMAL(31,19) | DECIMAL(31,24) |
DECIMAL(18,17) | DECIMAL(20,19) | DECIMAL(31,29) | DECIMAL(31,31) |
DECIMAL(16,3) | DECIMAL(17,8) | DECIMAL(31,9) | DECIMAL(31,11) |
DECIMAL(26,5) | DECIMAL(11,0) | DECIMAL(31,3) | DECIMAL(31,5) |
DECIMAL(21,1) | DECIMAL(15,1) | DECIMAL(31,2) | DECIMAL(31,2) |
SELECT MULTIPLY_ALT(98765432109876543210987.654,5.43210987) FROM SYSIBM.SYSDUMMY1Returns the value 536504678578875294857887.5277415.
Note that the complete product of these two numbers is 536504678578875294857887.52774154498, but the last 4 digits are truncated to match the scale of the result data type. Using the multiplication operator with the same values will cause an arithmetic overflow, since the result data type is DECIMAL(31,11) and the result value has 24 digits left of the decimal, but the result data type only supports 20 digits.
(C) Copyright IBM Corporation 1992, 2006. All Rights Reserved.