How to Retrieve the Current Value of an Oracle Sequence Without Incrementing?

Retrieving Oracle Sequence Values Without Incrementing

To obtain the current value of an Oracle sequence without incrementing it, the following SQL statement can be used:

SELECT last_number
  FROM all_sequences
 WHERE sequence_owner = '<sequence owner>'
   AND sequence_name = '<sequence_name>';

This statement retrieves the last number generated by the specified sequence without modifying the sequence value.

Alternatively, the following views can provide sequence metadata, including the last generated value:

• user_sequences: For sequences in the current user's default schema
• all_sequences: For sequences accessible to the current user
• dba_sequences: For all sequences (for users with appropriate privileges)

For example, to retrieve the current value of a sequence named "SEQ" in the default schema:

SELECT last_number
  FROM user_sequences
 WHERE sequence_name = 'SEQ';

Note that the cache size of the sequence can impact the reliability of this method. If the cache size is greater than 1, the sequence may have cached multiple values that can be retrieved without incrementing. To address this, the sequence's increment can be set to a negative value, then back to its original value, as shown in the following example:

-- Set the sequence to decrement by the same as its original increment
ALTER SEQUENCE seq INCREMENT BY -1;

-- Retrieve the sequence value
SELECT seq.nextval FROM dual;

-- Reset the sequence to its original increment
ALTER SEQUENCE seq INCREMENT BY 1;

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