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Adding members in the middle of the list causes renumbering of existing members, which requires a table copy. 

## Generated Column Operations 

The following table provides an overview of online DDL support for generated column operations. For details, see Syntax and Usage Notes. 

<img src='content_image/754461.jpg'>

## Syntax and Usage Notes 

•Adding a STORED  column 

ALTER TABLE t1 ADD COLUMN (c2 INT GENERATED ALWAYS AS (c1 + 1) STORED), ALGORITHM=COPY; 

ADD COLUMN  is not an in-place operation for stored columns (done without using a temporary table) because the expression must be evaluated by the server. 

•Modifying STORED  column order 

ALTER TABLE t1 MODIFY COLUMN c2 INT GENERATED ALWAYS AS (c1 + 1) STORED FIRST, ALGORITHM=COPY; 

Rebuilds the table in place. 

•Dropping a STORED  column 

ALTER TABLE t1 DROP COLUMN c2, ALGORITHM=INPLACE, LOCK=NONE; 

Rebuilds the table in place. 

•Adding a VIRTUAL  column 

ALTER TABLE t1 ADD COLUMN (c2 INT GENERATED ALWAYS AS (c1 + 1) VIRTUAL), ALGORITHM=INSTANT; 

