How Can I Find Missing Auto-Incrementing IDs in My SQL Database Table?

Use SQL to find missing IDs in a table

In database tables with auto-incrementing primary keys, deleted entries can create "holes" in field values. To identify these missing IDs, you can write a query.

MySQL and SQL Server queries:

<code class="language-sql">SELECT ID + 1
FROM table_name
WHERE ID + 1 NOT IN (SELECT DISTINCT ID FROM table_name);</code>

This query will provide a list of all consecutive missing IDs between the first and last entry in the table.

SQLite query:

<code class="language-sql">SELECT DISTINCT id +1
FROM table_name
WHERE id + 1 NOT IN (SELECT DISTINCT id FROM table_name);</code>

SQLite does not support the LIMIT keyword, so use distinct subqueries to avoid duplicate results.

Other notes:

• This query assumes the first ID is 1.
• This query does not include any deleted IDs higher than the current maximum ID.
• To include deleted IDs between the current maximum and the specified MaxID parameter, modify the query as follows:

<code class="language-sql">SELECT ID + 1
FROM table_name
WHERE ID + 1 NOT IN (
  SELECT DISTINCT ID FROM table_name
)
AND ID + 1 < MaxID;</code>

Please note that this modification may not be supported by all versions of SQLite.

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