How to Reset an MySQL AutoIncrement using a MAX value from another table?

Question

I know this won\'t work, tried it in various forms and failed all times. What is the simplest way to achieve the following result?

ALTER TABLE XYZ AUTO_INCRE         


        

Answer 1

Personally I'd probably use either a shell script or a little C#/C++ application or PHP/Ruby/Perl script to do this in 2 queries:

• Grab the value you want SELECT MAX(ID) FROM ABC;
• Alter the table using the value ALTER TABLE XYZ AUTO_INCREMENT = <insert value retrieved from first query here>

Obviously being careful that the new auto increment won't cause any key clashes with existing data in the XYZ table.

Answer 2

following the mysql docs, this worked for me in mysql 5.7:

SET @m = (SELECT MAX(id) + 1 FROM ABC); 
SET @s = CONCAT('ALTER TABLE XYZ AUTO_INCREMENT=', @m);
PREPARE stmt1 FROM @s;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;