Approximate Record Count in Firebird

The following solution was originally posted to the Firebird Support Mail List by Ivan Prenosil.This solution only returns an approximate record count*, and will include records that have been deleted (and not yet garbage collected) as well as records that have been inserted but not yet committed.

Code:
/* first update the statistics */
UPDATE RDB$INDICES SET RDB$STATISTICS = -1;
COMMIT;

/* Display table names and record counts */
SELECT RDB$RELATIONS.RDB$RELATION_NAME,CASE WHEN RDB$INDICES.RDB$STATISTICS = 0 THEN 0 ELSE CAST(1 / RDB$INDICES.RDB$STATISTICS AS INTEGER) END FROM RDB$RELATIONS LEFT JOIN RDB$RELATION_CONSTRAINTS ON RDB$RELATIONS.RDB$RELATION_NAME = RDB$RELATION_CONSTRAINTS.RDB$RELATION_NAME AND RDB$CONSTRAINT_TYPE = 'PRIMARY KEY'LEFT JOIN RDB$INDICES ONRDB$RELATION_CONSTRAINTS.RDB$INDEX_NAME = RDB$INDICES.RDB$INDEX_NAME WHERE RDB$VIEW_BLR IS NULL ANDRDB$RELATION_ID >= 128 ORDER BY 1;


* This will only work on tables that have a primary key.