How to clear data from a certain column without deleting it in mysql

How do I clear data from a column and then set the first value as 1 with auto increment? I do not want to delete the column, merely to reset it.

edit:开发者_StackOverflow中文版 This is for my mysql database

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1. TRUNCATE TABLE tbl -- will erase everything from the table
2. ALTER TABLE tbl AUTO_INCREMENT = 1

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Do not do it.
Auto-increment column is untouchable by design.

If you reset it, you will break your application.

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UPDATE TABLE SET col=0;

UPDATE Table AS T1 SET T1.col=1+ (SELECT MAX(T2.COL) FROM TABLE AS T2)

That should do it.