SQL Reference

Predicates

A predicate specifies a condition that is true, false, or unknown about a given row or group.

Supported predicats are as follows:

• Basic Predicate
• Quantified Predicate
• BETWEEN Predicate
• EXISTS Predicate
• IN Predicate
• LIKE Predicate
• NULL Predicate
• TYPE Predicate

The following rules apply to all types of predicates:

• All values specified in a predicate must be compatible.
• An expression used in a Basic, Quantified, IN, or BETWEEN predicate must not result in a character string with a length attribute greater than 4 000, a graphic string with a length attribute greater than 2 000, or a LOB string of any size.
• The value of a host variable may be null (that is, the variable may have a negative indicator variable).
• The code page conversion of operands of predicates involving two or more operands, with the exception of LIKE, are done according to Rules for String Conversions
• Use of a DATALINK value is limited to the NULL predicate.
• Use of a structured type value is limited to the NULL predicate and the TYPE predicate.

A fullselect is a form of the SELECT statement which is described under Queries. A fullselect used in a predicate is also called a subquery.