Logical Operators

Table 1. Logical Operator Precedence
Operator	Purpose	Precedence
`NOT`	Negation of a search condition	1
`AND`	Combines two or more predicates, each of which must be true for the entire predicate to be true	2
`OR`	Combines two or more predicates, of which at least one predicate must be true for the entire predicate to be true	3

Table 1. Logical Operator Precedence

Operator

Purpose

Precedence

NOT

Negation of a search condition

AND

Combines two or more predicates, each of which must be true for the entire predicate to be true

OR

Combines two or more predicates, of which at least one predicate must be true for the entire predicate to be true

`NEXT VALUE FOR`

Result type

BIGINT — dialect 2 and 3
INTEGER — dialect 1

Syntax

NEXT VALUE FOR sequence-name

NEXT VALUE FOR returns the next value of a sequence.Sequence is the SQL-standard term for what is historically called a generator in Firebird and its ancestor, InterBase.The NEXT VALUE FOR operator is equivalent to the legacy GEN_ID (…, increment) function with increment the increment stored in the metadata of the sequence.It is the recommended syntax for retrieving the next sequence value.

Note

Unlike the GEN_ID function, the NEXT VALUE FOR expression does not take any parameters and thus provides no way to retrieve the current value of a sequence, nor to step the next value by a different value than the increment configured for the sequence.GEN_ID (…, <step value>) is still needed for these tasks.A step value of 0 returns the current sequence value.

The increment of a sequence can be configured with the INCREMENT clause of CREATE SEQUENCE or ALTER SEQUENCE.

In dialect 1, the result type is INTEGER, in dialect 2 and 3 it is BIGINT.

Example

NEW.CUST_ID = NEXT VALUE FOR CUSTSEQ;