在先前删除的行ID的位置插入列的新值，而不是在最后插入的行ID之后

Question

I want to assign values to a column In this manner

1,2,3,4,5,...1000

If I insert values for column

1,2,3,4,5,6,7

Using auto increment Now I want to delete 2,3 And the next insertion should be 2,3, not 8 After 2,3 is completed then my insertion should start with 8 ...

Answer 1

AUTO_INCREMENT behaves like this; it doesn't fill the gaps arising from deleted data, it just appends the new entries to the "bottom" of the current enumeration. This is because, in a vast majority of cases, it's a very bad practice to reuse unique identifiers.

There is pretty much nothing you can do about it... except changing the design of your table so that the identifier field doesn't have the AUTO_INCREMENT property and, then, implementing your own logic to fill the gaps upon insertion. Finding the smallest unused identifier and assigning it to the upcoming insertion is pretty easy:

SET @GapId = (
    SELECT MIN(T1.ID + 1)
    FROM MyTable T1
    LEFT JOIN MyTable T2 ON T2.ID = T1.ID + 1
    WHERE T2.ID IS NULL
);

INSERT INTO MyTable(ID,...) VALUES (@GapId,...);