Binary comparison operators

Use binary comparison operators to compare numeric and string values for equality and inequality.

The following table describes the comparison operators supported by the ObjectServer.

Table 1. Comparison operators
Operator Description Example
= Tests for equality. SELECT * FROM london.status WHERE Severity = 3;
!=

<>

 Tests for inequality. SELECT * FROM london.status WHERE Severity <> 1;
<

>

<=

>=

 Tests for greater than (>), less than (<), greater than or equal to (>=) or less than or equal to (<=).

These operators perform case-sensitive string comparisons. In standard ASCII case-sensitive comparisons, uppercase letters come before lowercase letters.

 SELECT * FROM london.status WHERE Severity > 5;
%=

%!=

%<>

 Tests for equality (%=) or inequality (%!=, %<>) between strings, ignoring case. To be equal, the strings must contain all of the same characters, in the same order, but they do not need to have the same capitalization. SELECT * FROM london.status WHERE Location %= 'New York';
%<

%>

%<=

%>=

 Compares the lexicographic relationship between two strings, ignoring case. This comparison determines whether strings come before (%<) or after (%>) other strings alphabetically. You can also find strings that are less than or equal to (%<=) or greater than or equal to (%>=) other strings.

For example, aaa comes before AAB because alphabetically aaa is less than (comes before) AAB when the case is ignored.

 SELECT * FROM london.status WHERE site_code %< 'UK3';
[NOT] LIKE The LIKE operator performs string comparisons. The string following the LIKE operator, which can be the result of a regular expression, is the pattern to which the column expression is compared.

The NOT keyword inverts the result of the comparison.

 SELECT * FROM london.status WHERE Summary LIKE 'down';

The result is all rows in which Summary contains the substring down.
The LIKE and NOT LIKE comparison operators allow regular expression pattern-matching in the string being compared to the column expression. Regular expressions are sequences of atoms that are made up of normal characters and metacharacters. An atom is a single character or a pattern of one or more characters in parentheses. Normal characters include uppercase and lowercase letters, and numbers. Metacharacters are non-alphabetic characters that possess special meanings in regular expressions. The ObjectServer supports two types of regular expression libraries:
  • NETCOOL: Use this default library for single-byte character processing.
  • TRE: This library enables usage of the POSIX 1003.2 extended regular expression syntax, and provides support for both single-byte and multi-byte character languages.