I have a column that is the same in 200 tables belonging to a single db
 and I want to change the datatype of that column in all the 200 tables at once
instead of going to each table and doing it once after the other, how can I write this query in MySQL ?

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Vikas GargAssociate Principal EngineerCommented:

You can find your columns and table from Information_schema table as where clause and then fire this query

SELECT concat('ALTER TABLE ' ,TABLE_NAME ,' MODIFY ' , COLUMN_NAME , ' varchar(5)')  cl FROM information_schema.COLUMNS where (your where condition)

This will give the the alter table query for all the columns.
Then you can run those queries at once.

Hope this will do for you

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MySQL Server

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