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Adding rows to a table with identity column page 4

How to reset auto increment values to avoid gaps (MySQL)?

Let's take the table considered on the previous page and insert into it 3 rows.

  1. CREATE TABLE test_Identity (
  2.      id int(11) NOT NULL AUTO_INCREMENT,
  3.       PRIMARY KEY  (id)
  4.     );
  5.     INSERT INTO test_Identity VALUES(),(),();
  6.     SELECT * FROM test_Identity;

id
1
2
3

If we shall delete the last row, numbering will proceed not with 3, but with 4. I.e. last value of the counter is kept and used at the subsequent addition of rows:

  1. DELETE FROM test_Identity WHERE id=3;
  2. INSERT INTO test_Identity VALUES();
  3. SELECT * FROM test_Identity;

id
1
2
4

There is a question: " Whether is it possible to make numbering proceeding from last available value? "
Apart from a question about what it is necessary for, the answer is - possible. But this value of the counter should be set manually. So,

  1. DELETE FROM test_Identity WHERE id=4;
  2. ALTER TABLE test_Identity AUTO_INCREMENT = 3;
  3. INSERT INTO test_Identity VALUES(),(),();
  4. SELECT * FROM test_Identity;

id
1
2
3
4
5

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