How Can I Find Gaps in a MySQL Auto-Increment Sequence?

Detecting Missing Numbers in MySQL Auto-Increment Columns

Many MySQL tables utilize auto-increment columns to ensure unique identification. However, data deletion or other operations can leave gaps in the sequential numbering. This query effectively pinpoints these gaps within a defined range:

SELECT (t1.id + 1) AS gap_starts_at,
       (SELECT MIN(t3.id) - 1 FROM arrc_vouchers t3 WHERE t3.id > t1.id) AS gap_ends_at
FROM arrc_vouchers t1
WHERE NOT EXISTS (SELECT t2.id FROM arrc_vouchers t2 WHERE t2.id = t1.id + 1)
HAVING gap_ends_at IS NOT NULL;

The query's output consists of:

• gap_starts_at: Indicates the starting point of a missing number sequence.
• gap_ends_at: Shows the endpoint of the missing sequence.

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