4 Expressions

Expressions are typically combinations of one or more functions, attributes, constants, or operators. Most expressions are simple combinations of functions and attributes.

• Supported data types
  This topic describes the format of data types supported by EQL.
• Operator precedence rules
  EQL enforces the following precedence rules for operators.
• Handling of literals and values
  This section discusses how characters, numeric values, and NULL values are used in EQL.
• Functions and operators
  EQL contains a number of built-in functions that process data. It also supports arithmetic operators.
• Using EQL results to compose follow-on queries
  You can select a value in an EQL result and use it to compose a follow-on query.
• Using LOOKUP expressions for inter-statement references
  In EQL, you can define statements and then refer to these statements from other statements via a LOOKUP expression.
• ARB
  ARB selects an arbitrary but consistent value from the set of values in a field.
• BETWEEN
  The BETWEEN expression determines whether an attribute's value falls within a range of values.
• CASE
  CASE expressions allow conditional processing in EQL, allowing you to make decisions at query time.
• COALESCE
  The COALESCE expression allows for user-specified NULL-handling. It is often used to fill in missing values in dirty data.
• CORRELATION
  CORRELATION computes the correlation coefficient between two numeric attributes for all rows within a group.
• HAS_REFINEMENTS
  HAS_REFINEMENTS computes whether a particular attribute has non-implicit refinements in the current navigation state.
• IN
  IN expressions perform a membership test.
• PERCENTILE
  PERCENTILE computes a specified percentile of the values of an attribute for all records in the group.
• RECORD_IN_FAST_SAMPLE
  RECORD_IN_FAST_SAMPLE is a row function that returns a Boolean indicating whether the current record is in the sample of the records in the named state.