SQL, how to update a table structure

By Flavio Copes

Learn how to change a SQL table structure with the ALTER TABLE command, adding a new column with ADD COLUMN or removing one with DROP COLUMN.

We can alter an existing table structure using the ALTER TABLE command, followed by the alteration you want to make:

ALTER TABLE people ADD COLUMN born_year INT;

This will add a new column with empty values:

 age |  name  | born_year 
-----+--------+-----------
  37 | Flavio |          
   8 | Roger  |          

To drop a column:

ALTER TABLE people DROP COLUMN born_year;

This will result in:

 age |  name  
-----+--------
  37 | Flavio
   8 | Roger

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