Modify column Vs change column

Question

I know, we can not rename a column using modify column syntax,but can change column syntax.

My question is: what is the main usage of

Answer 1

The difference is whether you want to change the column name, column definition or both.

CHANGE

Can rename a column or change its definition, or both.

ALTER TABLE t1 CHANGE a b BIGINT NOT NULL

MODIFY

Can change a column definition but not its name

ALTER TABLE t1 MODIFY b INT NOT NULL

RENAME COLUMN

Can change a column name but not its definition.

ALTER TABLE t1 RENAME COLUMN b TO a

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You can check the docs for the complete explanation.