An arithmetic expression that describes the computation to be performed.

You can use any of the operations and functions listed below, and you can incorporate field names in the expression:

Operations

• Addition (+)
• Subtraction (-)
• Multiplication (*)
• Division (/)
• Remainder (%)
• Exponentiation (^)

Functions

• sgn(x). Returns 1 if x is positive, 0 if x is zero, or -1 if x is negative.
• abs(x). Returns the absolute value of x.
• floor(x). Returns the greatest integer less than or equal to x.
• round(x). Returns the nearest integer to x.
• log(b,x). Returns the logarithm of x base b.
• min(x,y,...). Returns the smallest of all its arguments.
• max(x,y,...). Returns the largest of all its arguments.