Expressions

The SQL language distinguishes between expressions and conditions.

An expression may be either:

• Any constant

• Any field name

• An arithmetic expression involving:

  • Constants
  • Fields
  • The operators +, -, * and /
  • The column functions AVG, COUNT, MAX, MIN and SUM
  • The scalar functions (see Date/Time Arithmetic )

Date and time arithmetic is allowed, and date or time values may be assigned to character fields, but there is no other provision for operators or functions taking character or yes/no operands, or returning results of these types. However from version 4.523 the DP4 SQL Engine implements the non standard UPPER() function which takes a character argument and returns the argument converted to upper-case. Also if the result is used in a comparison in a predicate case will be ignored.