Operators

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Operators

The following operators can be used (with their normal meaning and precedence) for scalars:

Unary + and -
Can only be used with double and complex operands. They do not have a higher precedence than the binary operators.
E.g. -3^2 results in -9.
Unary ! (or NOT)
Logical NOT operator. Can only be used with Bool operands.
Binary ^, *, /, %, +, and -
% is the modulo operator. E.g. 3%1.4 results in 0.2 and -10%3 results in -1.
^ is the power operator. Note that because of the precedence rules -3^2 results in -9.
All operators are left-associative, except ^ which is right-associative; thus 2^1^2 results in 2.
Operator % can only be used for double operands, while the others can be used for double and complex operands. Operator + can also be used for:
- Addition (i.e., concatenation) of 2 strings.
- Addition of a double (converted to unit days) and a DateTime (resulting in a DateTime).
Operator - can also be used for:
- Subtraction of a double (converted to unit days) from a DateTime (resulting in a DateTime).
- Subtraction of 2 DateTimes (resulting in a double with unit days).
==, ! = mathend000#, > mathend000#, > = mathend000#, < mathend000#, and < = mathend000#
Can be used with any operand as long as their data types conform. Operator > mathend000#, > = mathend000#, < mathend000#, and < = mathend000# cannot be used for Regex. They use the norm for Complex values.
To be compliant with SQL = mathend000# can be used for = = mathend000# and < > mathend000# can be used for ! = mathend000#.
~, !~, and LIKE and NOT LIKE.
~ and !~ have to be used with regular expression constants.
LIKE exists for SQL compliancy. It operates on a string giving a pattern with special characters % (0 or more characters) and _ (any single character).
EXISTS and NOT EXISTS
Can be used to test if a subquery finds at least N matching rows. The value for N is taken from the LIMIT clause; if LIMIT is not given it defaults to 1. The subquery loop stops as soon as N matching rows are found. E.g.
```
    EXISTS(select from ::ANTENNA where NAME=''somename'' LIMIT 2)
```
results in T if at least 2 matching rows in the ANTENNA table were found.
IN and NOT IN
Can be used to test if a value is an element in a set of values, ranges, and/or intervals. (See the discussion of sets).
BETWEEN and NOT BETWEEN
Is a special form of IN with a single closed interval. It exists for SQL compliance. It can be used to test if a value is between two other values. E.g.
col BETWEEN 1 AND 3 and col in [1=:=3] are the same.
INCONE and NOT INCONE
Can be used to do a cone search. (See the discussion of cone search functions).
&& and | | mathend000#
Logical AND and OR operator.
To be compliant with SQL the words AND and OR can be used instead of the symbols. These words are case insensitive.
Also & and | mathend000# can be used.
These operators can only be used with Bool operands.

: The precedence order is:
^
unary +, -, !
*, /, %
+, -
==, !=, >, >=, <, <=, IN, INCONE, BETWEEN, EXISTS, LIKE, ~, !~
&&
||

All these operators can be used in the same way for arrays (also a mix of scalar and array).

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