ADD and SUBTRACT (+ and -)

Database Management Reference Manual

Expressions : Numeric (Real) Expressions : ADD and SUBTRACT (+ and -)


Synopsis	number + number	-> number
	number ‑ number	-> number
	+ number	-> number
	- number	-> number
Description	Add or subtract two numbers. They can also be used as unary operators at the beginning of a parenthesised sub-expression.
Side Effects	Units are consolidated across add and subtract and the result is returned in current units of the physical quantity, for example when current distance units are inches q (1ft + 100mm) will return 15.9in If only one value has a unit qualifier the other is assumed to be in current units of that physical quantity for example: q (1ft + 100 ) will return 112in If the two values have conflicting units a warning is issued and a value is returned with no units assuming both values are in the database units of their respective quantities which is mm and Kg in the example: q (1ft + 1kg ) will return 305.8
Example	1 + 2 -> 3.0 1 ‑ 2 -> 1.0 + 1 -> 1.0 - 1 -> -1.0
Errors	Floating point underflow.