how to add column if not exists in sqlite

To add a column to an SQLite table only if it doesn't already exist, you can use the following SQL statement:

ALTER TABLE table_name ADD COLUMN IF NOT EXISTS column_name column_definition;

Here, `table_name` is the name of the table you want to add the column to, `column_name` is the name of the column you want to add, and `column_definition` is the data type and other constraints for the new column.

The `IF NOT EXISTS` clause ensures that the column is only added if it doesn't already exist in the table.

For example, suppose you have a table named "employees" with columns "id", "name", and "email". If you want to add a column named "phone" only if it doesn't exist, you could use the following SQL statement:

ALTER TABLE employees ADD COLUMN IF NOT EXISTS phone TEXT;

This will add the "phone" column to the "employees" table with a data type of TEXT only if the column doesn't already exist.