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# Math Functions and Operators

Calculations are expressed using the following operators and functions: [2]Because this function has an embedded comma, any expression containing this must be enclosed in double quotes.

[3]This is an aggregate function and applies to the column x.

 + Addition - Subtraction (or unary minus) * Multiplication / Division ** Exponentiation abs(x) Absolute value of x sqrt(x) Square root of x exp(x) e raised to the x log(x) Natural log of x cos(x) Cosine of x (x in radians) sin(x) Sin of x (x in radians) atan(x) Arc tangent of x (in radians) min(x,y) Minimum of x and y max(x,y) Maximum of x and y asin(x) Arc sine of x (in radians) acos(x) Arc cosine of x (in radians) cosh(x) Hyperbolic cosine of x (x in radians) sech(x) Hyperbolic cosecant of x (x in radians) pi pi int4(x) Integer truncation of x mod(x,y) Remainder of x/y min(x) Minimum of x max(x) Maximum of x count(x) Count of x countu(x) Count of unique x sum(x) Sum of x sumu(x) Sum of unique x avg(x) Average of x avgu(x) Average of unique x
Relational operators  are =,!=,<,<=,>,>=. These return 0 for false and 1 for true. Logical operators and and or may also be used: and is denoted by * and or is denoted by +. Relational operators  =,!=,<,<=,>,>= and logical operators and, or, and not can be used in constraints, e.g., (SHOT!=37123)AND(NE>=2.5E13). Note that there are no spaces around the ``AND''.

Note: You can simulate the use of logical expressions (i.e. if then else) by using absolute value. For example, suppose that f is e1 if y is less than one and e2 if y is greater than one. Define an expression u = (abs(y-1) /(y-1) + 1)/2 and then define f = (1-u) e1 + (u) e2.

Note: Integer ratios are truncated in expression evaluation. If you ask for 20/100 to be retrieved the result is 0; if you ask for 20./100 the result is 0.2.

Next: SG Graphics and LOCUS Up: The LOCUS Database System Previous: Entering Commands from a

Marilee Thompson
Fri Jul 11 17:05:56 EDT 1997