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Sql Alter Table — Free Sql Tutorial

Learn Sql Alter Table in Sql with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

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TL;DR: Learn Sql Alter Table in Sql with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 14, 2026

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Sql Alter Table in Sql

ALTER TABLE modifies an existing table: add columns, drop columns, rename columns, change data types, add/drop constraints.

ADD COLUMN inserts a new column. DROP COLUMN removes a column (all its data is lost). MODIFY COLUMN changes datatype (may require data conversion).

Altering large production tables can lock them. In real apps, plan schema changes carefully to minimise downtime.

Sql Alter Table — Syntax

ALTER TABLE table_name
ADD COLUMN column_name datatype;

ALTER TABLE table_name
DROP COLUMN column_name;

ALTER TABLE table_name
MODIFY COLUMN column_name new_datatype;

ALTER TABLE table_name
RENAME COLUMN old_name TO new_name;

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